Hand-surgery terms, defined
A working reference of the anatomical structures, conditions, procedures, investigations, and outcome measures that recur across the articles and procedure pages on this site. Each entry is written in plain language for patients and links to the underlying clinical context.
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A
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A1 pulley
The first of the fibrous bands (pulleys) that hold the flexor tendons against the finger bones, lying at the base of the finger over the metacarpophalangeal joint. It is the band that thickens in trigger finger and is divided in a trigger finger release; the A2 and A4 pulleys are the ones that must be preserved.
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AAOS
American Academy of Orthopaedic Surgeons. The largest professional organisation of orthopaedic surgeons in the United States; publishes evidence-based clinical practice guidelines including the 2024 update on carpal tunnel syndrome management.
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Abductor digiti minimi cord
Pathological cord lying ulnar to the bundle of the little finger, derived from the abductor digiti minimi musculotendinous unit. Contributes to small-finger proximal interphalangeal contracture without affecting the radial neurovascular structures.
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Abductor pollicis brevis
Superficial thenar muscle innervated by the recurrent thenar branch of the median nerve. Abducts the thumb perpendicular to the palm — the basis of the standard manual test for median-nerve motor function.
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Abductor pollicis longus
A forearm muscle whose tendon passes through the first extensor compartment and inserts on the base of the thumb metacarpal; it moves the thumb away from the palm and steadies the thumb base. Its tendon usually has two or more slips, which can hide a separate compartment during surgery for De Quervain's tenosynovitis.
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Adrenaline
A hormone, also used as a medicine, that narrows small blood vessels. Mixed with a local anaesthetic, it reduces bleeding where it is injected and can make the numbness last longer. In hand surgery it allows many operations to be done without a tourniquet. Its effect builds up over the first half-hour or so after injection and wears off over several hours.
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Allen test
Bedside test of the collateral circulation of the hand: the patient makes a fist while the examiner occludes both wrist arteries, the hand is opened and one artery is released; return of colour within a few seconds (six classically, nine in the modified test) shows adequate flow through the released artery. Used before radial artery harvest, it is only moderately sensitive against Doppler, so a positive test calls for duplex imaging.
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ALT flap
A versatile soft-tissue flap from the lateral thigh, supplied by the descending branch of the lateral circumflex femoral artery. The most adaptable workhorse flap in modern reconstruction.
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Anatomical snuffbox tenderness
Tenderness on direct palpation of the depression on the dorsoradial wrist bounded by the EPL and EPB tendons, with the floor formed by the scaphoid. A traditional clinical sign of scaphoid injury.
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Angiosome
A three-dimensional territory of skin, fascia, muscle, and bone supplied by a single named source artery. Adjacent angiosomes communicate through choke vessels that can dilate to extend a flap's safe territory.
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Anterior oblique ligament
The palmar ligament of the trapeziometacarpal joint, attaching to the palmar beak of the thumb metacarpal. Pellegrini linked its attritional detachment to wear of the palmar joint surface, the classic lesion of thumb-base osteoarthritis; other studies find it thin and capsule-like, and robotic testing suggests it works with the dorsoradial ligament.
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Arthrodesis
An operation that removes the worn joint surfaces and holds the two bones still until they grow together into one, so the joint no longer moves. Its aim is to reduce pain and give a stable joint when other treatment has not helped. Movement at that joint is lost permanently, and the bones do not always join.
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Aspiration
Drawing fluid out of a cyst or a joint through a needle. For a ganglion it is quick and done in the clinic, sometimes guided by ultrasound or combined with a steroid injection, but the cyst comes back in about half of cases or more — more often than after surgical excision.
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ASSH
American Society for Surgery of the Hand. The principal professional organisation for hand surgeons in the United States; co-endorsed the 2024 AAOS clinical practice guideline on carpal tunnel syndrome.
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Avascular necrosis (AVN)
Death of bone tissue from interruption of vascular supply. In the scaphoid, AVN typically affects the proximal pole following waist or proximal pole fractures, where the dorsal ridge blood supply is disrupted.
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Axonotmesis
Seddon's intermediate grade of nerve injury: the axons are interrupted and undergo Wallerian degeneration, but the connective-tissue framework of the nerve is preserved to a varying degree. Sunderland subdivides it into second, third and fourth degrees according to whether the endoneurium and perineurium survive; recovery ranges from complete (second degree) to poor without surgery (fourth degree).
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Bands of Büngner
Longitudinal columns of proliferating Schwann cells that fill the empty endoneurial tubes of the distal nerve stump after Wallerian degeneration and guide regenerating axons back towards their targets. Their growth-supportive state is time-limited, which is one reason delayed repair does badly.
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Basal cell carcinoma
The most common skin cancer, arising from the basal cells of the epidermis. It grows slowly, is caused mainly by sun exposure, and very rarely spreads elsewhere, but it keeps invading local tissue if untreated. Usually cured by excision with a margin of normal skin.
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Boston Carpal Tunnel Questionnaire
Disease-specific patient-reported outcome measure for carpal tunnel syndrome, developed by Levine in 1993. Comprises an 11-item Symptom Severity Scale and an 8-item Functional Status Scale, each on a 1–5 Likert scale. The dominant outcome measure in CTS research and trial reporting.
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Bouchard node
A firm bony swelling at the middle (proximal interphalangeal) joint of a finger, formed by osteophytes in osteoarthritis of that joint. It is the middle-joint counterpart of the Heberden node at the end joint.
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Boutonnière deformity
A finger deformity characterised by flexion at the proximal interphalangeal joint and hyperextension at the distal interphalangeal joint, produced by chronic disruption of the central slip with volar migration of the lateral bands.
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Bowstringing
Anterior displacement of a flexor tendon away from the underlying phalanges during finger flexion, resulting from loss of the constraining annular pulleys (most consequentially A2 and A4). Visible as a cord across the palmar finger and clinically expressed as reduced flexion power, because the tendon's mechanical lever arm decreases as it travels along a chord rather than the curved path the pulleys would impose.
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Brachial plexus block
Regional anaesthesia in which an anaesthetist injects local anaesthetic, usually under ultrasound guidance, around the nerves of the brachial plexus so that the whole arm is numb and still for the operation. It allows longer hand operations and the use of an upper-arm tourniquet without a general anaesthetic, and gives pain relief for some hours afterwards.
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Breslow thickness
The depth of a melanoma in millimetres, measured under the microscope from the top of the granular layer of the epidermis to its deepest point. Introduced by Alexander Breslow in 1970, it is the strongest single predictor of outcome and sets the width of the wide local excision and whether a sentinel node biopsy is offered.
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Calcium pyrophosphate deposition (CPPD)
A condition in which calcium pyrophosphate crystals collect in joint cartilage. It can cause sudden painful joint swelling or long-term arthritis that resembles osteoarthritis. Finding crystals in fluid drawn from the joint confirms the diagnosis; doctors also consider symptoms and imaging. Older age, osteoarthritis, an overactive parathyroid gland, haemochromatosis and low magnesium make it more likely.
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Carpal tunnel
Fibro-osseous canal at the volar wrist, bounded by the carpal bones dorsally, the scaphoid and trapezium radially, the pisiform and hook of hamate ulnarly, and the transverse carpal ligament volarly. Transmits the nine flexor tendons of the digits and the median nerve.
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Carpal tunnel syndrome
Compressive neuropathy of the median nerve at the wrist, the most common entrapment neuropathy. Presents with nocturnal paraesthesia in the median distribution, positive provocative tests, and — in advanced disease — fixed sensory loss and thenar atrophy.
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Central cord
Midline distal continuation of the pretendinous cord into the digit; produces proximal interphalangeal joint contracture without bundle displacement.
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Central slip
The central component of the extensor mechanism over the proximal interphalangeal joint, inserting on the dorsal base of the middle phalanx. Disruption causes a boutonnière deformity.
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Cleland's ligament
Dorsal component of the digital fascia, running between the lateral digital sheet and the flexor tendon sheath, dorsal to the digital neurovascular bundle. Not typically involved in Dupuytren cord formation.
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Cold intolerance
Abnormal pain, stiffness or discomfort of the hand on exposure to cold after nerve or vascular injury. It affects more than half of patients after median or ulnar nerve repair, correlates with poor sensory recovery, does not diminish with time, and is measured with the Cold Intolerance Symptom Severity (CISS) questionnaire, on which a score above 30 is pathological.
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Collagenase clostridium histolyticum
Injectable bacterial collagenase used to lyse Dupuytren cords without open surgery. Marketed as Xiaflex (US, Asia-Pacific) and Xiapex (EU). Withdrawn from the European market by the marketing authorisation holder in March 2020 and discontinued in New Zealand in 2019. Remains an examination topic and a literature comparator.
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Complex regional pain syndrome
Chronic regional pain disorder following injury or surgery, characterised by disproportionate pain, sensory disturbance, autonomic dysregulation (skin colour, temperature, sweating), motor or trophic changes, and restricted range of motion. Diagnosis is by Budapest criteria. Reported in less than 5 per cent of cases after Dupuytren's surgery across all modalities.
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Corticosteroid injection
Injection of a steroid medicine into or around an inflamed or thickened structure — a tendon sheath, a joint, or a raised scar — to reduce swelling and pain. Used for trigger finger and carpal tunnel syndrome, and to flatten hypertrophic scars and keloids.
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CTS-6
Six-item clinical diagnostic instrument for carpal tunnel syndrome developed by Graham and colleagues (2006). Endorsed by the 2024 AAOS guideline as a stand-alone diagnostic tool in cases without atypical features, suspected polyneuropathy, or suspected cervical radiculopathy.
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Cubital tunnel syndrome
Compression of the ulnar nerve at the elbow within the cubital tunnel. The second most common upper-limb compression neuropathy after carpal tunnel syndrome. Presents with paraesthesia in the small and ulnar-half of the ring finger and weakness of intrinsic hand muscles.
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De Quervain's tenosynovitis
Painful thickening of the first extensor compartment at the wrist, so that the abductor pollicis longus and extensor pollicis brevis tendons no longer glide freely. It causes pain over the thumb side of the wrist on gripping and pinching, is commoner in women, after 40 and around pregnancy, and is treated with a splint, a steroid injection or, if these fail, surgical release.
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Dermofasciectomy
Operative excision of the diseased palmar fascia together with the overlying skin, with reconstruction by full-thickness skin graft. Reserved for recurrent disease and for primary surgery in the strongly diathetic patient. Reduces recurrence on the rationale that diseased fascia regenerates beneath unaffected skin but is markedly less likely to do so beneath a graft.
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Diathesis
Constitutional predisposition to a more aggressive disease course and higher recurrence risk. The Hindocha 2006 modified Dupuytren's diathesis uses five features: male sex, onset before age 50, bilateral disease, an affected parent or sibling, and Garrod's pads. Ethnicity is not retained, and Ledderhose or Peyronie's disease does not fulfil the modified ectopic-disease criterion.
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DIEP flap
Lower abdominal skin and fat used to reconstruct a breast on a perforator pedicle, without sacrificing the rectus abdominis muscle. The autologous standard for breast reconstruction.
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Digital neurovascular bundle
Bundle containing the proper digital artery, proper digital nerve, and accompanying veins, running along the radial and ulnar aspects of each finger, deep to Grayson's ligament and superficial to Cleland's ligament. Its position is normally predictable but is displaced by the spiral cord in Dupuytren's disease.
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DISI (dorsal intercalated segmental instability)
A pattern of carpal malalignment in which the lunate adopts an abnormally extended (dorsiflexed) position, typically following loss of the scaphoid's stabilising effect through fracture, non-union or ligamentous injury.
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Distal interphalangeal joint
The finger joint nearest the nail (DIP joint). It is the hand joint most often affected by osteoarthritis, and the place where Heberden nodes form.
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Distal radioulnar joint
The pivot joint between the head of the ulna and the sigmoid notch of the distal radius, which allows forearm rotation. It is stabilised mainly by the radioulnar ligaments of the triangular fibrocartilage complex. After a distal radius fracture its stability is tested once the radius has been fixed; instability may need immobilisation or repair.
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Dorsoradial ligament
A short, thick ligament on the dorsoradial side of the trapeziometacarpal joint, running from the trapezium to the base of the thumb metacarpal. It belongs to the dorsal ligament complex, which histological studies found thickest and most richly innervated, and sectioning studies found it more important for stability than the deep anterior oblique ligament.
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Double crush phenomenon
Coexistent compression of the same nerve at two distinct anatomical levels (e.g., cervical radiculopathy plus carpal tunnel compression) producing additive symptoms. Originally described by Upton and McComas in 1973.
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Dual-screw fixation
Internal fixation of a scaphoid fracture or non-union using two parallel headless compression screws to provide rotational stability, proposed for selected unstable fractures and revision cases.
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Dupuytren's contracture
Fixed flexion deformity of the digital joints produced by pathological cords arising in the palmar fascia, the clinical end-stage of Dupuytren's disease. The term refers to the contracture phenotype specifically, distinct from the disease as a whole, which includes pre-contracture nodular phases.
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Dupuytren's disease
Benign progressive fibroproliferative disorder of the palmar and digital fascia, classified by WHO 2020 as a palmar-type fibromatosis. Characterised by myofibroblast-driven formation of nodules and cords in the palmar aponeurosis, leading to progressive flexion contracture of the digits, most commonly the ring and little fingers.
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Dupuytren's nodule
Palpable subcutaneous thickening representing the earliest clinically visible stage of Dupuytren's disease. Composed of myofibroblast-rich proliferative tissue. Most commonly located at the base of the ring or little finger. Initially painless; may become tender during active proliferative phase. Predates the formation of contractile cords.
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Durkan compression test
Direct pressure applied by examiner thumbs over the median nerve at the carpal tunnel for 30 seconds; reproduction of paraesthesia in the median distribution is a positive result. Described by Durkan (1991); generally considered the most sensitive of the provocative tests.
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Eaton–Littler classification
Radiographic staging of thumb-base osteoarthritis from stage I to stage IV; the Eaton–Glickel version adds involvement of the scaphotrapeziotrapezoid joint. It is widely used for description and in examinations, but agreement between observers is only poor to moderate, worst for stages II and III, and the stage correlates loosely with symptoms.
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ECU synergy test
Provocative test for extensor carpi ulnaris tendinopathy (Ruland and Hogan, 2008): with the elbow on the table, the forearm supinated and the fingers extended, the patient radially abducts the thumb against resistance; the synergistic contraction of extensor carpi ulnaris reproduces dorsal ulnar wrist pain when the tendon is the source. It loads the tendon without stressing the intra-articular ulnar structures.
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Elbow flexion test
Provocative test for cubital tunnel syndrome: the elbow is held in full flexion, with the wrist extended in the original description, and reproduction of paraesthesia in the ulnar distribution within the chosen time is positive. Sensitivity depends on the protocol — three minutes originally, 30 or 60 seconds in most studies and much lower at five to ten seconds; adding pressure over the nerve or shoulder internal rotation raises it substantially.
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Electromyography
Needle recording of the electrical activity of skeletal muscle at rest and during voluntary contraction. After nerve injury it shows fibrillation potentials from denervated fibres (from one to four weeks), the loss or return of voluntary motor units and reinnervation potentials, complementing nerve conduction studies in localising the lesion and quantifying axon loss.
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Elson test
A bedside test for central-slip integrity in which the patient attempts to extend the proximal interphalangeal joint with the finger flexed over a table edge; an extensor lag or rigid distal interphalangeal joint indicates central-slip disruption.
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Endoneurium
The innermost connective-tissue layer of a peripheral nerve, enclosing each axon and its Schwann cells within the fascicle bounded by the perineurium. The endoneurial tube guides regenerating axons back to their original targets; its preservation distinguishes a second-degree (fully recovering) injury from a third-degree one.
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Endoscopic carpal tunnel release
Alternative technique for division of the transverse carpal ligament via one or two short incisions and an endoscope-guided cutting blade. Trial-level evidence shows broadly equivalent long-term outcomes to open release; the choice between techniques is driven by surgeon experience and patient factors.
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Erosive hand osteoarthritis
A form of hand osteoarthritis in which X-rays show bone erosions in the finger joints. It causes more pain and disability than other hand osteoarthritis and is much more common in women.
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Extensor mechanism
The composite tendon system over the dorsal aspect of the finger, formed by the extensor digitorum communis tendon together with contributions from the lumbrical and interosseous muscles, that collectively extends the metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints.
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Extensor pollicis brevis
A forearm muscle whose tendon runs through the first extensor compartment, beside the abductor pollicis longus, to the base of the thumb's proximal phalanx; it straightens the thumb's knuckle joint. It often lies in its own sub-compartment, which a steroid injection may miss and which must be found and opened at surgery for De Quervain's tenosynovitis.
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Extensor retinaculum
The band of thick fibrous tissue across the back of the wrist that holds the extensor tendons against the bones and divides them into six compartments. The part over the first compartment forms the roof of the tunnel that thickens in De Quervain's tenosynovitis and is opened at its surgical release.
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Facial reanimation
Surgical restoration of voluntary facial movement — particularly the smile — in patients with long-standing facial paralysis. Free gracilis muscle transfer with motor nerve reinnervation is the dominant technique.
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Fasciocutaneous flap
A flap of skin and underlying fascia, supplied by vessels travelling within or just above the deep fascia. Pontén's 1981 description of the lower-leg fasciocutaneous flap defined the class.
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FEBHS
Fellow of the European Board of Hand Surgery. A subspecialty diploma awarded by the Federation of European Societies for Surgery of the Hand (FESSH) following examination; formally recognises subspecialty hand surgery competence in Europe.
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Fibrillation potentials
Spontaneous electrical discharges of individual denervated muscle fibres recorded on needle electromyography. They appear one to four weeks after an axonal nerve injury, later for proximal lesions, and their amplitude declines over the following year, which helps date an injury of uncertain age.
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Fibro-osseous canal
Anatomical channel with bony walls and a fibrous roof. The carpal tunnel is the prototypical example — bony floor and walls formed by the carpal bones, fibrous roof formed by the transverse carpal ligament.
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Fibula flap
Vascularised bone from the lower leg, with or without a skin paddle, used principally for segmental reconstruction of the mandible after tumour resection and for long-bone defects.
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Finger splint
A small splint that supports a painful finger joint, made to measure or ready-made and often worn at night. For osteoarthritis of the end joint, small studies suggest night splinting can ease pain; randomised trials are lacking.
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Finkelstein test
A test for De Quervain's tenosynovitis: the examiner grasps the patient's thumb and gently deviates the wrist towards the little finger, reproducing pain over the first extensor compartment. The commonly taught version with the thumb tucked into a fist is Eichhoff's test, which is more painful and gives more false positives in healthy wrists.
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Firebreak graft
Full-thickness skin graft inserted at primary fasciectomy at a flexion crease, intended to interrupt cord-disease progression. Concept introduced by Hueston in 1984. The 2009 Ullah randomised trial found no significant difference in recurrence between firebreak FTSG and Z-plasty closure at 36 months; not a contemporary default at primary fasciectomy.
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First extensor compartment
The fibro-osseous tunnel over the radial styloid through which the abductor pollicis longus and extensor pollicis brevis tendons pass under the extensor retinaculum. A septum divides it fully or partly in many wrists, more often in people with De Quervain's tenosynovitis, and the abductor pollicis longus often has several slips — both relevant to injection and to surgical release.
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First metacarpal extension osteotomy
An osteotomy at the base of the thumb metacarpal, derived from Wilson's basal osteotomy, that tilts the metacarpal into extension and shifts joint contact from the worn palmar compartment to the dorsal one. It is considered for early trapeziometacarpal osteoarthritis; pooled data suggest pain relief without gain in grip or pinch strength.
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Flexor pollicis brevis
Thenar muscle with two heads — superficial (recurrent thenar branch of median nerve) and deep (deep branch of ulnar nerve). The dual innervation explains residual thumb flexion strength after isolated median or ulnar palsy.
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Flexor retinaculum
Composite ligamentous structure at the volar wrist with three components: the proximal antebrachial fascia, the central transverse carpal ligament, and the distal aponeurotic continuation between thenar and hypothenar muscles. The transverse carpal ligament is the load-bearing portion in carpal tunnel pathology.
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Flexor sheath ganglion
A small, firm ganglion arising from the flexor tendon sheath of a finger, usually at the A1 or A2 pulley near the base of the digit. It feels like a pea, is tender when gripping, and lies between the digital neurovascular bundles. It often recurs after puncture and rarely after excision with a small window of the sheath.
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Four-corner fusion
A motion-preserving salvage procedure for advanced wrist arthrosis in which the scaphoid is excised and the lunate, capitate, hamate and triquetrum are fused, preserving the radiolunate articulation.
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Fracture liaison service
A coordinated service that identifies adults presenting with a fragility fracture, such as a low-energy wrist fracture, and arranges assessment of bone health and falls risk with treatment to prevent further fractures. Meta-analyses associate it with more bone-density testing and treatment and fewer subsequent fractures.
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Free flap
A piece of living tissue — skin, muscle, bone, or any combination — deliberately disconnected from one part of the body and reattached at another, with its own artery and vein joined under the microscope to vessels at the recipient site. The defining feature is microvascular anastomosis.
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Froment's sign
Sign of adductor pollicis weakness in ulnar nerve palsy: when the patient pinches a sheet of paper between thumb and index finger against a pull, flexor pollicis longus substitutes for the weak adductor and the thumb interphalangeal joint flexes. Hyperextension of the thumb metacarpophalangeal joint in the same manoeuvre is Jeanne's sign. Both are motor signs that appear with established weakness and may be absent in early compression.
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Full-thickness skin graft
A skin graft that includes the whole epidermis and dermis, taken from a donor site that is then closed directly — in front of or behind the ear, above the collarbone, the inner upper arm or the groin. It contracts little and matches facial skin well, but needs a well-vascularised bed and a still, padded dressing to take.
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Ganglion cyst
A benign cyst filled with thick, clear mucin and joined by a stalk to a nearby joint capsule or tendon sheath; its wall has no true synovial lining. It is the commonest lump of the hand and wrist and arises most often on the back of the wrist over the scapholunate ligament, on the front of the wrist beside the radial artery, from a finger's flexor tendon sheath, or as a mucous cyst at the end joint. About half resolve without treatment.
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Garrod's pads
Knuckle pads at the dorsal aspect of the proximal interphalangeal joints, an ectopic manifestation of the Dupuytren diathesis. Histologically related to the palmar disease and a recognised diathesis criterion.
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Genome-wide association study
Hypothesis-free statistical interrogation of single-nucleotide polymorphisms across the genome for association with disease phenotype. The foundational GWAS in Dupuytren's disease is Dolmans 2011 (New England Journal of Medicine), identifying nine susceptibility loci, six harbouring Wnt-pathway genes.
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Germinal matrix
The tissue under the proximal nail fold that produces the nail plate. A mucous cyst lying over it can press on it and cause a longitudinal groove in the nail, which often grows out after the cyst is excised; injury to the matrix at surgery can leave a permanent nail deformity.
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Grayson's ligament
Volar component of the digital fascia, running between the lateral digital sheet and the flexor tendon sheath, volar to the digital neurovascular bundle. Contributes to spiral cord formation in Dupuytren's disease.
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Great toe-to-thumb transfer
A microsurgical reconstruction of the thumb after traumatic amputation, in which the great toe (or part of it) is transferred from the foot with its dorsalis pedis artery, saphenous vein, and digital nerves, and revascularised at the wrist. Variants include the full toe (Cobbett 1969), the wrap-around (Morrison 1980), and the trimmed great toe (Wei).
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Haematoma distraction arthroplasty
Trapeziectomy in which the thumb metacarpal is held distracted, usually with a temporary K-wire, so that the space left by the trapezium fills with haematoma and then scar, without a tendon sling or interposition. The scaphoid–metacarpal distance falls with time, but this has not correlated with strength or function.
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Haemochromatosis
An inherited condition in which the body stores too much iron. Its joint disease typically affects the knuckle joints of the index and middle fingers, often years before diagnosis. Blood tests (transferrin saturation and ferritin) are the first step. Removing iron by regular blood draws protects the liver and other organs, but established joint changes often do not improve.
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Hand elevation test
Provocative test for carpal tunnel syndrome described by Ahn in 2001: the patient raises both hands above the head and holds them there until symptoms appear or the time limit is reached; median-distribution paraesthesia is positive. In the original series it was 75.5 per cent sensitive and 98.5 per cent specific, and a 2022 meta-analysis gave it the highest pooled diagnostic odds ratio of the common provocative manoeuvres.
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Hand therapist
A physiotherapist or occupational therapist with additional postgraduate training and clinical experience in rehabilitation of the hand and upper limb. After hand surgery or injury, a hand therapist assesses the hand, teaches exercise programmes, makes custom splints (orthoses), treats swelling and scars, and advises on daily activities and return to work, working closely with the surgeon.
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Healing by secondary intention
Leaving a wound open to heal on its own, by filling with granulation tissue and then skin growing in from the edges, instead of closing it with stitches, a flap or a graft. It takes weeks and needs regular dressings; on concave sites of the face it can give an excellent result.
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Heberden node
A firm bony swelling at the back of a finger's end (distal interphalangeal) joint, formed by osteophytes in osteoarthritis of that joint. A mucous cyst often arises beside one, and the osteophytes are commonly trimmed when the cyst is excised.
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Herbert classification
The most widely used European classification of scaphoid fractures, grouping injuries by stability and chronicity into types A (stable acute), B (unstable acute, B1–B5), C (delayed union) and D (established non-union).
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Hook of hamate
Volar bony projection of the hamate, forming the ulnar wall of the carpal tunnel. A palpable landmark approximately 2 cm distal and 2 cm radial to the pisiform; in carpal tunnel surgery, used as a topographical reference to keep the incision and dissection ulnar to the median nerve.
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Hueston tabletop test
Functional indication-for-surgery test described by Hueston (The Hand 1982). The patient attempts to lay the palm and fingers flat against a level surface; inability to achieve full flat-palm contact is a positive test. Used as a clinical threshold for considering operative correction, alongside patient-reported impairment.
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Humpback deformity
A flexion deformity of the scaphoid following waist fracture or non-union, in which the distal fragment flexes relative to the proximal fragment, producing a dorsal apex (humpback) on the lateral view and disrupting carpal alignment.
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Hypertrophic scar
A raised, often red scar that stays within the boundary of the original wound. Unlike keloids, hypertrophic scars often improve gradually over time.
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Indocyanine green fluorescence angiography
Use of an injected fluorescent dye, indocyanine green, viewed under near-infrared light to visualise blood and lymphatic flow in real time during surgery — used to assess flap perfusion and to map lymphatic vessels.
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Intravenous regional anaesthesia
A way of numbing the forearm and hand for surgery. A tourniquet is inflated on the arm and local anaesthetic is injected into a vein below it, so the drug stays in the limb while the tourniquet is up. Discomfort from the tourniquet can mean that sedation is needed.
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Intrinsic tightness test
Bunnell's test for tightness of the intrinsic muscles: passive flexion of the proximal interphalangeal joint is compared with the metacarpophalangeal joint held in extension and in flexion. Less proximal interphalangeal flexion with the metacarpophalangeal joint extended indicates tight intrinsics, because extension of that joint stretches the lumbrical and interosseous tendons; the reverse pattern indicates tight extrinsic extensors.
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ITAMe
Intraoperative Total Active Movement Examination — testing of a flexor tendon repair under active patient flexion before wound closure, possible only with awake-patient anaesthesia (WALANT). Higgins and colleagues identified gapping or instability under active flexion in seven patients in their original 2010 series; all seven were re-repaired and none subsequently ruptured.
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Kanavel signs
The four cardinal signs of pyogenic flexor tenosynovitis: fusiform swelling of the digit, a semi-flexed resting posture, tenderness along the flexor tendon sheath and pain on passive extension. Individually they are 91–97 per cent sensitive but only 51–69 per cent specific against other finger infections; sheath tenderness, pain on passive extension and symptoms of under five days are the independent predictors of a sheath infection.
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Kaplan's cardinal line
Surface marking line drawn from the apex of the first web space across the palm, parallel to the proximal palmar crease. Approximates the level of the superficial palmar arch and the distal extent of safe dissection in carpal tunnel release.
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Keloid
A raised scar that grows beyond the boundary of the original wound and does not tend to shrink on its own. Keloids can be itchy or tender and have a tendency to come back after treatment.
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Key pinch
The grip between the pad of the thumb and the side of the index finger, as when turning a key, measured with a pinch gauge in kilograms. The strength most affected by thumb-base arthritis and the outcome that separates the operations: it fades over years after trapeziectomy and is about 0.9 kg stronger after joint replacement in pooled trials.
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Knuckle (MCP) joint replacement
An operation that replaces a damaged knuckle joint with an implant — either a one-piece silicone spacer or a two-part implant that resurfaces both sides of the joint. It aims to relieve pain and keep some movement; implants can break, loosen or need further surgery.
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Lafontaine criteria
Factors read from the first radiograph of a distal radius fracture to predict secondary displacement after closed reduction, described by Lafontaine in 1989: dorsal tilt over 20°, dorsal comminution, intra-articular radiocarpal involvement, an associated ulnar fracture and comminution, with age over 60 as an additional factor. Later studies found their discrimination modest.
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Lateral bands
The two paired bands of the extensor mechanism that pass alongside the proximal interphalangeal joint and unite distally to form the terminal tendon over the distal interphalangeal joint.
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Lateral cord
Pathological cord derived from the lateral digital sheet; displaces the digital neurovascular bundle medially, less dramatically than the spiral cord but relevantly so.
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Ledderhose disease
Plantar fibromatosis — a benign fibroproliferative disorder of the plantar fascia, histologically related to Dupuytren's disease and sharing the myofibroblast-driven mechanism. A recognised ectopic manifestation of the Dupuytren diathesis.
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Ligament reconstruction and tendon interposition
An addition to trapeziectomy in which a strip of a forearm tendon is used to make a sling for the thumb metacarpal and to fill the space left by the trapezium. Trials pooled in the 2026 Cochrane review show it makes little or no difference to pain, function or complications compared with trapeziectomy alone, and complications were about 19 in 100 against 10 in 100.
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Limited fasciectomy
Open surgical excision of the diseased palmar and digital fascia through a Bruner-zigzag or longitudinal-Z-plasty incision, with preservation of normal fibres. The contemporary operative workhorse for Dupuytren's contracture. Lower five-year recurrence than percutaneous needle fasciotomy at the cost of greater up-front morbidity, longer recovery, and a higher rate of nerve and vessel injury.
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Local anaesthetic systemic toxicity
A potentially life-threatening toxic effect that occurs when too much local anaesthetic reaches the bloodstream. It most often affects the nervous system, sometimes with seizures, and can affect the heart and circulation. The risk depends on the drug, the dose and how it is given, which is why the total amount used is limited.
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Local flap
A piece of skin and underlying tissue moved from next to a wound into the wound while it stays attached to its own blood supply. Because the skin comes from the same area, its colour and thickness match well. Common types are advancement, rotation and transposition flaps.
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Lunotriquetral ballottement test
Reagan's test for lunotriquetral ligament injury: the examiner stabilises the lunate with one hand and displaces the triquetrum and pisiform dorsally and palmarly with the other; pain, crepitus or excessive laxity is positive. Against arthroscopy it is about 64 per cent sensitive and 44 per cent specific. Kleinman's shear test loads the same joint by pushing the pisiform dorsally against a stabilised lunate.
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Lymphaticovenular anastomosis
Surgical connection of small lymphatic vessels directly to subdermal venules to provide physiological drainage in lymphedematous tissue. Performed under supermicrosurgical conditions.
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Lymphedema
Chronic swelling of a limb caused by impaired lymphatic drainage, most commonly after lymph node removal or radiotherapy in the treatment of cancer.
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M-Tang technique
A four- or six-strand multistrand core suture technique for primary flexor tendon repair, formalised by Tang JB. Combines adequate purchase length (0.7–1 cm in each tendon end), modest tension calibrated to slight bunching at the repair site, locking grasps rather than simple grasps, and a peripheral epitendinous mattress.
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McFarlane cord pattern
The classical taxonomy of pathological cords in Dupuytren's contracture. McFarlane's 1974 dissection of 69 contracted fingers in 50 consecutive cases named five diseased cords — pretendinous, central, spiral, lateral and natatory — and showed that three (central, spiral, lateral) contract the proximal interphalangeal joint. The retrovascular cord was added by McFarlane in 1985, the abductor digiti minimi and commissural cords by later authors.
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Medial femoral condyle (MFC) flap
A free vascularised corticoperiosteal flap from the medial femoral condyle, anastomosed to recipient vessels at the wrist, used to reconstruct proximal pole scaphoid non-union with avascular necrosis.
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Median nerve
Mixed motor and sensory nerve formed from the medial and lateral cords of the brachial plexus (C5–T1). Supplies most of the volar forearm flexors, the radial-side hand intrinsics via the recurrent thenar branch, and the volar skin of the thumb, index, middle, and radial half of the ring finger.
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Melanoma
A cancer of the pigment-producing cells (melanocytes) of the skin. It is the most serious of the common skin cancers because it can spread to the lymph nodes and other organs; found early, it is usually cured by excision. New Zealand and Australia have the highest rates in the world.
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Melanoma in situ
A melanoma confined to the epidermis, the top layer of the skin, that has not yet grown into the dermis. It cannot spread to the lymph nodes or elsewhere and is cured by complete excision with a 5–10 mm margin.
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Metacarpophalangeal (MCP) joint
The joint at the base of each finger, between a metacarpal bone and the first bone of the finger — the knuckle seen when making a fist. It bends and straightens the finger at its base and lets the fingers spread apart.
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Microvascular anastomosis
Joining of small blood vessels (typically less than 3 mm) under an operating microscope using sutures finer than a human hair.
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Motor end plate
The neuromuscular junction at which a motor axon terminal meets the muscle fibre. After denervation the end plate can maintain its integrity for up to about a year, but progressive muscle fibrosis makes functional reinnervation unlikely beyond 12–18 months — the window that drives early repair and nerve transfer.
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MRC grading
The Medical Research Council scales used to grade recovery after nerve repair: motor power from M0 (no contraction) to M5 (normal), and sensation from S0 (absent) to S4 (complete recovery), with S3 the return of superficial pain and tactile sensibility without over-response. In outcome research, M4–M5 and S3+–S4 are conventionally called satisfactory recovery.
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Mucous cyst
A ganglion of the distal interphalangeal joint, lying on the back of the finger between the end joint and the nail fold. It is associated with osteoarthritis of the joint and its osteophytes (Heberden nodes), can groove the nail by pressing on the nail matrix, and recurs least often when the joint is debrided at the time the cyst is excised.
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Myofibroblast
Specialised contractile fibroblast expressing α-smooth muscle actin, responsible for the cellular contraction of the involutional phase of Dupuytren's disease. The cell type targeted by anti-TNF therapy in the RIDD trial. Population reactivation from residual proliferative foci is the cellular substrate of recurrence.
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Natatory ligament
Transverse fibre arrangement at the level of the distal palmar crease, contributing to the interdigital webbing in pathological states. May be involved in Dupuytren's disease as a natatory cord, contributing to interdigital contracture.
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Nerve conduction studies
Electrodiagnostic investigation that measures distal motor latency, sensory nerve action potential amplitude, and conduction velocity along peripheral nerves. In carpal tunnel syndrome, prolonged distal motor latency and reduced sensory nerve action potential amplitude define disease severity.
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Nerve conduit
A hollow tube of silicone, polyglycolic acid, collagen or autogenous vein used to bridge a short nerve gap by enclosing the nerve ends and letting the nerve regenerate across the space. Supported by randomised trials for short gaps in sensory nerves (a few millimetres to about 2–3 cm); not a substitute for autograft in motor or mixed nerves, proximal injuries or gaps over 3 cm.
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Nerve graft
A segment of expendable sensory nerve, most often the sural or an upper-limb cutaneous nerve, interposed as one or several reversed cables to bridge a gap that cannot be closed without tension. Millesi's interfascicular grafting showed it beats suture under tension; it remains the standard for motor or mixed nerves, proximal injuries and gaps over 3 cm, at the cost of donor numbness and a second coaptation.
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Nerve transfer
Coaptation of an expendable donor nerve or fascicle to the distal stump of an injured nerve close to its target, converting a proximal injury into a distal one with a single tension-free repair and no graft. Used for brachial plexus and high nerve injuries and for delayed presentations within the motor reinnervation window; the Oberlin and anterior interosseous-to-ulnar transfers are the classic examples.
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Neurapraxia
The mildest grade of nerve injury (Seddon; Sunderland first degree): segmental demyelination with the axon and connective-tissue sheaths intact, usually from compression. It produces a focal conduction block with preserved conduction distal to the lesion and no Wallerian degeneration; recovery is complete, typically within about twelve weeks, once remyelination occurs.
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Neuroma-in-continuity
A scarred, thickened segment of an injured nerve that remains in anatomical continuity, in which regenerating axons are trapped in fibrous tissue and a variable number cross to the distal stump. Whether to neurolyse it or to resect and graft it is decided by time, examination and intraoperative nerve action potential recording, because no pre-operative test grades it reliably.
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Neurotmesis
Seddon's most severe grade of nerve injury (Sunderland fifth degree): complete transection of the nerve, its axons and all connective-tissue layers. No useful spontaneous recovery is possible; the nerve must be repaired, grafted or bypassed by a nerve transfer.
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Non-union
Failure of two bone ends to knit together after a fracture or a fusion operation. After a finger-joint fusion it is not always painful; a painful non-union may need a second operation.
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Non-vascularised bone graft (NVBG)
A bone graft harvested without preserving its blood supply, relying on creeping substitution from the recipient bed. Common donor sites for scaphoid reconstruction are the iliac crest and distal radius.
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NSAID
Non-steroidal anti-inflammatory drug — a class of analgesics that inhibits cyclo-oxygenase enzymes (COX-1 and COX-2) to reduce prostaglandin-mediated pain and inflammation. The 2024 AAOS guideline supports an NSAID and/or paracetamol for pain relief after carpal tunnel release.
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Oberlin transfer
Transfer of one or two fascicles, about 10 per cent of the bulk of the ulnar nerve, directly to the motor branch to biceps to restore elbow flexion after C5–C6 brachial plexus avulsion, described by Oberlin in 1994 without significant loss of hand function. The double fascicular modification adds a median nerve fascicle to the brachialis branch.
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Opponens pollicis
Deep thenar muscle innervated by the recurrent thenar branch of the median nerve. Rotates the first metacarpal and flexes it across the palm to oppose the thumb to the small finger.
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Osteocutaneous flap
A composite flap that includes a vascularised segment of bone together with an overlying skin paddle, supplied by a single shared vascular pedicle. The skin component is typically supplied by fasciocutaneous perforators arising from the bone's source artery. Standard examples include the free fibula osteocutaneous flap and the iliac crest (DCIA) osteocutaneous flap.
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Osteophyte
A bony outgrowth at the margin of a joint, formed in osteoarthritis. At the distal interphalangeal joint osteophytes form Heberden nodes and are thought to drive the formation of mucous cysts; they are commonly trimmed with a rongeur when a mucous cyst is excised.
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Palmar aponeurosis
Triangular sheet of dense connective tissue overlying the long flexor tendons in the palm, with longitudinal, transverse, and vertical fibre bundles. The longitudinal fibres condense into the pretendinous bands. The aponeurosis becomes the source tissue for cord formation in Dupuytren's disease.
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Palmar cutaneous branch of the median nerve (PCBMN)
Sensory branch arising from the median nerve 4–6 cm proximal to the wrist crease, running superficial to the flexor retinaculum to supply the skin of the thenar eminence. Injury produces a tender neuroma or numb patch at the thenar base.
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Palmodigital spiralling sheet
Continuous spiralling structure connecting palmar and digital fascia at the palmodigital junction, described by Malsagova, Zwanenburg, and Werker in the Journal of Hand Surgery (European Volume) 2019. Refines the conventional segmental description of the palmodigital fascia and explains why neurovascular bundles can be displaced into the digital midline by spiral-cord disease.
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Patient-Rated Wrist Evaluation (PRWE)
A 15-item validated patient-reported outcome measure scoring wrist pain and function on a 0–100 scale, where lower scores indicate better outcome. The primary outcome measure of the SWIFFT trial.
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Patient-reported outcome measures (PROM)
Standardised questionnaires used to measure outcomes from the patient's perspective. In Dupuytren's disease, the most commonly validated instruments include URAM (9 items, Dupuytren-specific, FESSH-preferred), DASH/QuickDASH (general upper extremity, less Dupuytren-sensitive), and Michigan Hand Questionnaire (63 items, six domains).
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Pedicled flap
A flap of tissue moved to a nearby site while still attached to its original blood supply, in contrast to a free flap whose pedicle is divided and reconnected at the new site.
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Percutaneous needle fasciotomy
Office-based percutaneous division of the Dupuytren cord with a small-bore (typically 25-gauge) needle under skin-wheal local anaesthesia, indicated for palpable pretendinous-cord contracture in selected primary disease. Reintroduced in the late 1970s by the French rheumatologist Lermusiaux. Shorter recovery and higher recurrence than limited fasciectomy.
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Perforator
A small blood vessel that pierces the deep fascia to supply the skin and subcutaneous tissue from a deeper source artery. Classified by route — direct (straight from a main trunk through fascia), septal (through intermuscular septa), or musculocutaneous (through a muscle before reaching skin). Clinically usable perforators measure 0.5-1.5 mm.
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Perforator flap
A flap raised on a small vessel that pierces the deep fascia to supply the skin, leaving the underlying muscle intact. Conceptualised by Koshima and Soeda in 1989.
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Peyronie's disease
Penile fibromatosis — a benign fibroproliferative disorder of the tunica albuginea, histologically related to Dupuytren's disease. A recognised ectopic manifestation of the Dupuytren diathesis.
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Phalen test
Provocative test for carpal tunnel syndrome described by George Phalen (1966). The patient holds the wrist in maximal volar flexion for 60 seconds; reproduction of paraesthesia in the median distribution is a positive result.
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Phentolamine
A medicine that reverses the narrowing of blood vessels caused by adrenaline. If a finger stays pale after an injection of local anaesthetic with adrenaline, phentolamine injected at the same site helps its colour return sooner. In a large prospective series of hand surgery with adrenaline it was never needed.
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Pillar pain
Discomfort at the thenar and hypothenar bases on direct pressure or firm grip following carpal tunnel release, distinct from the incision site. Affects 13–49% of patients depending on definition; usually self-limiting by 3–6 months.
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PIP joint replacement (arthroplasty)
An operation that replaces a worn PIP joint (the middle joint of a finger) with an implant. The two main types are a one-piece flexible silicone implant and a two-part surface replacement that replaces the ends of both bones forming the joint.
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Pisiform
Sesamoid bone in the tendon of flexor carpi ulnaris on the volar-ulnar aspect of the proximal carpal row; forms the ulnar wall of the carpal tunnel together with the hook of hamate.
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Platelet-rich plasma
A concentrate of the patient's own platelets, prepared by spinning a blood sample, injected into a joint or tendon in the hope of stimulating healing. For thumb-base arthritis a single injection did no better than a saline placebo at six months in a double-blind randomised trial, and pooled trials show no advantage over corticosteroid.
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Posterior interosseous nerve
The deep motor branch of the radial nerve in the forearm. Its terminal branch runs on the floor of the fourth extensor compartment to the back of the wrist capsule, carrying sensation from the joint. It lies in the field of dorsal ganglion excision; a short segment may be excised (neurectomy) to reduce wrist pain, although its benefit at ganglion surgery has not been shown.
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Pretendinous band
Longitudinal condensation of the palmar aponeurosis overlying each digital flexor tendon, running from the apex of the aponeurosis to the proximal phalanx. The normal structure that, when thickened, becomes the pretendinous cord.
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Pretendinous cord
Pathological cord derived from the pretendinous band; produces metacarpophalangeal joint contracture. Does not displace the digital neurovascular bundle. The cord pattern most clearly indicated for percutaneous needle fasciotomy.
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Processed nerve allograft
A decellularised human cadaveric nerve segment that retains the basal lamina and endoneurial architecture, used off the shelf to bridge a nerve gap without donor-site morbidity. Randomised and registry data show better sensory recovery than hollow conduits and results comparable to autograft in short gaps; its upper length limit and its role in motor nerves remain debated.
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Pronator syndrome
Compression of the median nerve in the proximal forearm — at the lacertus fibrosus, between the heads of pronator teres, or at the proximal arch of flexor digitorum superficialis. Causes proximal median symptoms that may mimic carpal tunnel syndrome but typically with daytime forearm aching and tenderness over pronator teres.
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Proximal interphalangeal joint
The middle joint of a finger (PIP joint), between the first and middle finger bones. It bends the finger in the middle; in osteoarthritis Bouchard nodes form here.
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Proximal row carpectomy (PRC)
A motion-preserving salvage procedure for advanced wrist arthrosis in which the scaphoid, lunate and triquetrum are excised, allowing the capitate to articulate with the lunate fossa of the radius.
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Radial forearm flap
Thin, pliable skin flap from the volar forearm raised on the radial artery. The standard flap for intra-oral reconstruction; the donor scar on the forearm is its principal drawback.
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Reconstructive ladder
A traditional framework for reconstructive decision-making — choose the simplest method that will close the wound, ascending in complexity from direct closure through skin graft, local flap, regional flap, to free tissue transfer.
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Recurrent motor branch of the median nerve
Motor branch of the median nerve to the thenar muscles (abductor pollicis brevis, opponens pollicis, and superficial head of flexor pollicis brevis). Lanz described extraligamentous, subligamentous, and transligamentous variants. Lies radial to the median nerve at the carpal tunnel — preserved by ulnar-side entry into the tunnel.
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Relative motion orthosis
A finger splint that holds the affected digit in fifteen to twenty degrees of metacarpophalangeal hyperextension relative to its uninjured neighbours, transferring extensor force away from the repair through the juncturae tendinum and permitting early protected active motion.
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Relaxed skin tension lines
The lines along which the skin is under least tension, running at right angles to the pull of the underlying muscles and visible as furrows when the skin is pinched. An ellipse placed along them closes with less tension and heals with a thinner, less conspicuous scar.
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Replantation
Reattachment of a part of the body that has been completely separated, with restoration of its own blood circulation through microvascular anastomosis.
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Retrovascular cord
Pathological cord in Dupuytren's disease running deep (dorsal) to the digital neurovascular bundle. It does not flex the proximal interphalangeal joint on its own, but if left behind it prevents full correction of that joint and causes recurrence; with the lateral cord it produces distal interphalangeal joint contracture. The cord most commonly missed at primary surgery; found by deliberate dorsal exploration of the bundle.
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Rheumatoid arthritis
A long-term inflammatory disease of the joint lining that commonly affects the small joints of the hands, including the knuckle (MCP) joints. Untreated, it can damage joints and cause deformity such as drifting of the fingers towards the little finger. It is diagnosed and treated by a rheumatologist, with disease-modifying medicines started early.
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RIDD trial
Repurposing anti-TNF for Dupuytren Disease — a phase 2b randomised, double-blind, placebo-controlled trial of intranodular adalimumab in early-stage disease, published by Nanchahal and colleagues in Lancet Rheumatology 2022. Demonstrated softening and reduction in nodule size at 12 months; phase 3 progression pending as of 2026.
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Sagittal band
The transverse fibrous structure at the metacarpophalangeal joint that centralises the extensor digitorum communis tendon over the knuckle. Disruption causes ulnar tendon subluxation.
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Scaphoid
The most lateral bone of the proximal carpal row, articulating with the radius and four other carpal bones. Boat-shaped, with proximal pole, waist, and distal tubercle. Approximately 80% covered by articular cartilage; the dorsal ridge is the principal vascular entry.
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Scapholunate ligament
The ligament joining the scaphoid and the lunate in the proximal row of wrist bones; its thick dorsal part is the main stabiliser of the scapholunate joint. Most dorsal wrist ganglia arise from the capsule over it, so its fibres are preserved during ganglion excision. A tear can lead to scapholunate instability, tested with the Watson scaphoid shift test.
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Scaphotrapeziotrapezoid joint
The joint between the scaphoid and the trapezium and trapezoid, immediately proximal to the thumb-base joint. Arthritis here, alone or with the trapeziometacarpal joint (pantrapezial arthritis), has traditionally favoured trapeziectomy, which removes the trapezium from both joints; recent series report good results of joint replacement in selected thumbs.
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Scar contracture
Tightening of scar tissue that can pull on surrounding skin and, when it crosses a joint, limit movement. Common after burns.
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SCIP flap
Thin groin-area skin flap raised on a small perforator using supermicrosurgical technique, with a donor scar that hides in the bikini line. Described by Koshima in 2004.
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Scratch collapse test
A provocative test described by Cheng and Mackinnon in 2008 in which scratching skin over a compressed nerve produces transient loss of resisted shoulder external rotation. Original sensitivity ~64% has not been replicated under blinded conditions; not recommended as a sole diagnostic test.
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Seddon classification
Seddon's three-grade classification of peripheral nerve injury, published in 1942–1943: neurapraxia (segmental demyelination with an intact axon), axonotmesis (axonal interruption with a preserved connective-tissue framework) and neurotmesis (complete transection). It remains the classification used in most clinical descriptions.
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Semmes-Weinstein monofilaments
Calibrated nylon filaments that buckle at a known force, applied to the skin to measure the threshold of light-touch pressure perception. As a threshold test the monofilament changes early in nerve compression, before two-point discrimination, which makes it sensitive for carpal tunnel syndrome; its specificity depends on the filament chosen as the cut-off, and its inter-observer reliability is lower than that of other sensory tests.
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Sensory re-education
A programme of graded tactile exercises, begun early or late after nerve repair, that trains the cortex to reinterpret the altered input from a reinnervated hand. First formalised by Dellon, Curtis and Edgerton in 1974; immediate re-education with audio-tactile feedback improved tactile gnosis in a randomised trial, while the evidence for conventional programmes remains limited.
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Sentinel lymph node biopsy
Removal of the first lymph node (or nodes) that drain the skin around a melanoma, located with a radioactive tracer and a blue dye, to check for microscopic spread. A staging test that guides follow-up and further treatment; offered for melanomas 1 mm thick or more, or 0.8 mm with high-risk features.
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Serpentine zone
The zone of danger for the digital neurovascular bundle in Dupuytren's contracture, described by Macey and Thomas (Journal of Hand and Microsurgery, 2018): a spiral cord displaces the bundle towards the midline and closer to the skin. A surface-marking guide for incision planning in limited fasciectomy.
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Silicone gel therapy
Silicone applied as a gel or an adhesive sheet, used to help flatten and soften raised scars and to reduce redness. A widely used first-line, non-surgical scar treatment.
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Skin graft
A thin layer of skin removed from one part of the body and placed on a wound elsewhere; survives initially by absorbing nutrients before new blood vessels grow in from the wound bed.
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SNAC wrist (scaphoid non-union advanced collapse)
The pattern of progressive wrist osteoarthritis that develops over years from untreated scaphoid non-union. Three Watson stages: I radial styloid arthrosis; II scaphocapitate; III periscapholunate with capitolunate involvement.
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Soong classification
A grading of volar plate prominence on the lateral radiograph. A line is drawn tangential to the most volar point of the volar rim, parallel to the volar cortex of the shaft: grade 0 plates stay behind it, grade 1 plates lie in front of it but short of the rim, and grade 2 plates sit on or beyond the volar rim. Grade 2 prominence is associated with flexor tendon rupture.
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Spiral cord
Pathological cord formed by the confluence of the pretendinous band, spiral band, lateral digital sheet, and Grayson's ligament. Displaces the digital neurovascular bundle palmarly, centrally toward the digital midline, and proximally — most marked at the level of the proximal phalanx. The principal anatomical reason needle fasciotomy is contraindicated for established proximal interphalangeal contracture.
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Split-thickness skin graft
A skin graft of the epidermis and part of the dermis, shaved with a dermatome from a donor site (usually the thigh) that heals on its own under a dressing. It takes more reliably and covers larger wounds than a full-thickness graft, but contracts more and looks paler and shinier than the surrounding skin.
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Squamous cell carcinoma
The second most common skin cancer, arising from the keratinocytes of the epidermis. It grows faster than basal cell carcinoma and spreads to lymph nodes in a small proportion of cases, particularly when large, thick, on the ear or lip, or in immunosuppressed people. Most are cured by excision.
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Stener lesion
Displacement of the torn ulnar collateral ligament of the thumb metacarpophalangeal joint proximal and superficial to the adductor aponeurosis, so that the aponeurosis lies between the ligament and its insertion and healing cannot occur without surgery. It accompanies most complete ruptures with marked valgus instability in extension; ultrasound (pooled sensitivity 95 per cent, specificity 94 per cent) is the first-line imaging test.
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Stenosing tenosynovitis
The medical name for trigger finger: narrowing of the flexor tendon tunnel at the A1 pulley so that the tendon catches. Despite the name, histology shows little inflammation; the pulley undergoes fibrocartilaginous change. The same term is used for De Quervain's tenosynovitis at the wrist.
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Subsynovial connective tissue
The connective tissue layer surrounding the flexor tendons within the carpal tunnel, providing a gliding interface between them. Non-inflammatory thickening and fibrosis of the SSCT is the dominant histopathological finding in idiopathic carpal tunnel syndrome.
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Sunderland classification
Sunderland's 1951 five-degree classification of nerve injury by the connective-tissue layer lost: first degree (neurapraxia), second (axon only, endoneurium intact — full recovery), third (endoneurium disrupted — partial recovery), fourth (perineurium disrupted — usually needs surgery) and fifth (complete transection). Mackinnon and Dellon added a sixth degree for mixed injuries.
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Supercharged end-to-side transfer
End-to-side coaptation of the distal anterior interosseous nerve to the ulnar motor branch, leaving the injured ulnar nerve in continuity, described by Barbour and Mackinnon. Intended for second- and third-degree axonotmetic injuries and severe compression, to augment partial recovery or to 'babysit' the intrinsic motor end plates until native axons regenerate; not a replacement for repair of a complete transection.
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Superficial palmar arch
Vascular arch in the palm formed predominantly by the ulnar artery with a contribution from the superficial branch of the radial artery. Lies on average about 10–12 mm distal to Kaplan's cardinal line — the practical reason a carpal tunnel release incision stops well proximal to that line.
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Superficial radial nerve
The sensory branch of the radial nerve that runs under the skin of the forearm to supply feeling over the back of the thumb and the web space. Its branches often cross the first extensor compartment, so they are protected during surgery there; handling them can cause temporary tingling, and injury can leave numbness or a painful neuroma.
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Supermicrosurgery
Microvascular surgery on vessels 0.8 mm in diameter or smaller, requiring specialised instruments, ultra-fine sutures, and additional training. Defined formally by the Barcelona consensus in 2014.
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Surgical margin
The rim of normal-looking tissue removed around a tumour so that its microscopic extensions are included. The clinical margin is measured on the skin before excision; the histological margin is the distance from the tumour to the cut edge under the microscope, usually reported as clear (at least 1 mm), close (under 1 mm) or involved.
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Swan-neck deformity
A finger deformity characterised by hyperextension at the proximal interphalangeal joint and flexion at the distal interphalangeal joint, often a late complication of untreated mallet finger or volar plate insufficiency.
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Tendon transfer
An operation that restores a lost movement by moving a working tendon, with its muscle, to take over the job of one that no longer works. The tension of the transfer is set during the operation. Under WALANT the patient can move the hand before the skin is closed, so the surgeon can check and adjust it.
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Tenolysis
Surgical division of peritendinous adhesions where mature scar tissue tethers a previously repaired or grafted tendon to the surrounding sheath. Indicated when active range of motion is restricted despite full passive motion six months or more after the index repair, and only when the underlying repair is intact.
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Thenar atrophy
Visible wasting of the thenar eminence muscles (abductor pollicis brevis, opponens pollicis, superficial head of flexor pollicis brevis) — a late sign of severe motor compromise of the recurrent thenar branch of the median nerve in advanced carpal tunnel syndrome.
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Thenar eminence
Muscular bulge at the radial base of the palm formed by abductor pollicis brevis, opponens pollicis, the superficial head of flexor pollicis brevis, and adductor pollicis (ulnar nerve innervation). Median-nerve innervation of the first three is the substrate for thenar atrophy in advanced carpal tunnel syndrome.
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Thumb joint replacement
Replacement of the worn thumb-base joint with a small ball-and-socket implant, keeping the thumb at its full length. Compared with trapeziectomy in randomised trials it gives similar pain relief and hand-function scores, faster recovery and a stronger pinch, with a risk of implant loosening, dislocation or wear; ten-year results for modern dual-mobility designs are not yet available.
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Thumb splint
A splint that supports the base of the thumb, worn at night or during heavy tasks. In a randomised trial a custom splint made no difference at one month but reduced pain and disability at twelve months; a rigid splint holding both thumb joints was the one non-operative treatment with a clear medium-term benefit in a review of 22 trials.
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Thumb-base arthritis
Wear of the cartilage in the saddle-shaped joint between the trapezium and the base of the thumb metacarpal. The commonest site of hand arthritis after the fingertip joints, more frequent in women and with age; it causes pain at the base of the thumb on pinching and gripping, and in late stages a zigzag deformity. X-ray severity correlates poorly with symptoms.
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Tinel sign
Percussion over a peripheral nerve elicits paraesthesia in its sensory distribution; described by Jules Tinel in 1915 as a marker of regenerating axons. After nerve repair an advancing sign marks the regeneration front (about 1 mm a day distally) but does not predict functional recovery. Positive over the median nerve at the wrist, it supports a diagnosis of carpal tunnel syndrome.
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Total passive extension deficit
Sum of fixed flexion contracture across the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints in an affected ray, measured by goniometer at maximal passive extension. The principal goniometric outcome measure in the operative literature on Dupuytren's disease, including the van Rijssen 2012 trial.
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Tourniquet
An inflatable cuff placed around the upper arm or forearm and pumped up to keep the operating area free of blood, giving the surgeon a clear view. An inflated tourniquet is uncomfortable for an awake person, so it is often combined with a regional block, sedation or a general anaesthetic. WALANT avoids it by using adrenaline instead.
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Trans-scaphoid perilunate injury
A high-energy carpal injury in which the scaphoid fractures and the surrounding carpus dislocates around the lunate, classified as Herbert B4. Requires urgent reduction and surgical fixation.
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Transverse carpal ligament
Thickened central portion of the flexor retinaculum forming the roof of the carpal tunnel. Spans from the scaphoid tubercle and trapezial ridge radially to the pisiform and hook of hamate ulnarly. Division of this ligament is the operative substance of carpal tunnel release.
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Trapeziectomy
Removal of the trapezium so that the worn thumb-base joint no longer exists; the space fills with scar tissue and the thumb settles slightly. The standard operation for painful thumb-base arthritis, with good pain relief in about four in five people at five to eighteen years; pinch strength does not return to normal. Adding a tendon sling or spacer makes little or no difference.
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Trapeziometacarpal joint denervation
Division of the small sensory nerve branches that supply the thumb-base joint, leaving the joint itself intact, to relieve the pain of osteoarthritis. Recovery is quick and later surgery is not excluded, but there is no randomised trial and series report reoperation, usually conversion to trapeziectomy, in up to about 30 per cent.
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Trapezium
The most radial bone of the distal carpal row, articulating with the first metacarpal at the trapeziometacarpal joint. Forms the radial wall of the carpal tunnel together with the scaphoid.
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Trigger finger
A condition in which a finger or thumb catches, clicks or locks as it bends, because the flexor tendon no longer glides freely through the thickened first (A1) pulley at the base of the digit. Common in people in their fifties and sixties and in people with diabetes.
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Tubiana classification
Five-stage assessment of Dupuytren's contracture severity by total flexion deformity of an affected ray (sum of MCP, PIP, and DIP extension deficits): stage 0 (no disease), stage N (nodule, no contracture), stage 1 (0–45°), stage 2 (46–90°), stage 3 (91–135°), stage 4 (>135°). Described by Tubiana, Michon, and Thomine in 1968.
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Two-point discrimination
The smallest distance at which two points touching the skin simultaneously are perceived as separate, tested statically or with the points moving, and used to grade discriminative sensation after nerve repair. Technique is poorly standardised and the cut-offs for excellent, good and poor results vary between authors, so comparisons between series are unreliable.
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Ulnar fovea sign
Tenderness on pressing the examiner's thumb into the soft spot between the ulnar styloid and flexor carpi ulnaris that reproduces the patient's pain. In Tay and Berger's arthroscopic series it was 95 per cent sensitive and 87 per cent specific for foveal disruption of the radioulnar ligaments or an ulnotriquetral ligament injury; the two are separated clinically by the stability of the distal radioulnar joint.
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Ulnar variance
The difference in length between the articular surfaces of the distal ulna and the distal radius on a neutral-rotation posteroanterior radiograph, recorded as positive when the ulna is longer and negative when it is shorter. After a distal radius fracture, an increase reflects shortening of the radius.
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Ultrasound
Real-time imaging using high-frequency sound waves; in carpal tunnel syndrome, used to measure median nerve cross-sectional area at the tunnel inlet (typical threshold 9 mm²), to identify anatomical variants (bifid nerve, persistent median artery), and to guide corticosteroid injection or percutaneous release.
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Ultrasound-guided percutaneous carpal tunnel release
An emerging minimally invasive surgical technique in which the transverse carpal ligament is divided percutaneously under real-time ultrasound guidance, without an open incision. Multiple device approaches exist (hook knife, sono-instruments, threadwire). The 2024 AAOS guideline acknowledges UCTR but does not endorse it over standard techniques.
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URAM scale
Unité Rhumatologique des Affections de la Main scale — a 9-item Dupuytren-specific patient-reported outcome measure for hand function, developed and validated by Beaudreuil and colleagues (Arthritis Care and Research 2011). The FESSH-preferred disease-specific outcome instrument; minimal clinically important difference is 2.9 points.
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Vascular pedicle
The artery, vein, and surrounding tissue that supply blood to a flap. The reliable size and position of a flap depend on the anatomy of its pedicle.
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Vascularised bone graft (VBG)
A bone graft that retains its vascular supply through a pedicle or microsurgical anastomosis. In scaphoid surgery, VBG is preferred over non-vascularised graft for proximal pole non-union with avascular necrosis.
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Vascularised composite allotransplantation
Transplantation of composite tissue (such as a hand or face) from a deceased donor, requiring lifelong immunosuppression to prevent rejection. Performed in a small number of specialist centres worldwide.
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Vascularised lymph node transfer
Transplantation of a small group of lymph nodes with their vascular pedicle (typically from the groin, supraclavicular fossa, or omentum) to a limb affected by lymphedema.
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Vinculum
Mesenteric folds within the synovial flexor tendon sheath conveying segmental blood supply from the digital arteries to the flexor tendons. Each tendon typically receives a vinculum breve (short, near the insertion) and a vinculum longum (long, more proximal); precise anatomy varies considerably between digits and between individuals.
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Volar locking plate
A plate applied to the palmar (volar) surface of the distal radius through an anterior approach, with screws that lock into the plate at a fixed angle and support the joint surface from below. It allows early movement; its specific complications include flexor tendon irritation or rupture when it sits too far distally and extensor tendon injury from screws that are too long.
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WALANT
Wide-awake local anaesthesia no tourniquet. Lignocaine with adrenaline is injected at the operation site, so a hand operation can be done without a tourniquet, sedation or a general anaesthetic. The patient stays awake and can move the hand when asked, so the surgeon can check movement before the skin is closed. Whether it suits a particular person depends on the operation, their circulation and general health, and their preference.
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Wallerian degeneration
The programmed breakdown of the axon and its myelin distal to a nerve injury that has interrupted the axon, beginning within 24–48 hours. Schwann cells shed myelin and proliferate, macrophages clear the debris, and the empty endoneurial tubes are lined by bands of Büngner along which regenerating axons later grow. It does not occur in neurapraxia.
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Wartenberg's sign
Persistent abduction of the little finger with inability to adduct it actively to the ring finger, seen in ulnar nerve palsy: the unopposed extensor and abductor digiti minimi abduct the finger while the weak third palmar interosseous cannot bring it back. It is also seen during ulnar nerve regeneration, occurs rarely without a neuropathy, and is distinct from Wartenberg's syndrome, the compression of the superficial radial nerve.
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Wartenberg's syndrome
Compression of the superficial radial nerve in the forearm, causing burning pain, tingling or numbness over the back of the thumb and hand that is worse with wrist movement. It can coexist with De Quervain's tenosynovitis and should be recognised before the first extensor compartment is released. It is different from Wartenberg's sign, a finding in ulnar nerve palsy.
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Watson scaphoid shift test
Provocative test for scapholunate instability described by Watson: the examiner's thumb presses on the palmar tubercle of the scaphoid while the wrist moves from ulnar to radial deviation; painful dorsal subluxation of the scaphoid over the dorsal rim of the radius is positive. A painless positive test occurs in a third of uninjured lax wrists, so pain is the discriminating feature; the positive likelihood ratio against arthroscopy is about 2.9.
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WHAT test
Wrist hyperflexion and abduction of the thumb test for De Quervain tenosynovitis: with the wrist hyperflexed the patient abducts the thumb against resistance, reproducing first-compartment pain. Against ultrasound it was 0.99 sensitive but only 0.29 specific, so a negative test is more useful than a positive one; its authors also use it to detect dynamic instability of the first-compartment tendons after release.
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Wide local excision
The second operation after a melanoma is diagnosed: removal of a measured margin of normal-looking skin and fat around the biopsy scar, down to the fascia, to clear any remaining cancer cells. The margin, 5 mm to 2 cm, is set by the Breslow thickness.
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Wrist arthroscopy
Examination or surgery of the wrist joint through a few small incisions, using a thin camera and fine instruments passed into the joint. For a wrist ganglion it is an alternative to open excision.