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.
1
A
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
B
-
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.
-
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.
-
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.
C
-
Carpal tunnel
Fibro-osseous canal at the volar wrist, bounded by the proximal carpal row volarly, the scaphoid and trapezium radially, the pisiform and hook of hamate ulnarly, and the transverse carpal ligament dorsally. Transmits the nine flexor tendons of the digits and the median nerve.
-
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.
-
Central cord
Midline distal continuation of the pretendinous cord into the digit; produces proximal interphalangeal joint contracture without bundle displacement.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
D
-
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.
-
Diathesis
Constitutional predisposition to a more aggressive disease course and higher recurrence risk. The Hindocha 2006 modification of the original Hueston 1963 diathesis adds male sex and onset before age 50 to the original four features (Northern European descent, bilateral disease, ectopic disease, family history); the cumulative count predicts recurrence.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
E
-
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.
-
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.
-
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.
F
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
G
-
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.
-
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.
-
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.
-
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).
H
-
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).
-
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.
-
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.
-
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.
I
-
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.
-
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.
J
K
L
-
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.
-
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.
-
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.
-
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.
-
Lymphaticovenular anastomosis
Surgical connection of small lymphatic vessels directly to subdermal venules to provide physiological drainage in lymphedematous tissue. Performed under supermicrosurgical conditions.
-
Lymphedema
Chronic swelling of a limb caused by impaired lymphatic drainage, most commonly after lymph node removal or radiotherapy in the treatment of cancer.
M
-
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.
-
McFarlane cord pattern
The classical taxonomy of pathological cords in Dupuytren's contracture — pretendinous, central, spiral, lateral, retrovascular, abductor digiti minimi, and first-web cords — described by McFarlane in Plastic and Reconstructive Surgery 1974 from a dissection of 69 contracted fingers in 50 consecutive cases. The operative anchor for surgical anatomy across all modalities.
-
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.
-
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.
-
Mella serpentine zone
Surface anatomy of the digital neurovascular spiral in Dupuytren's contracture, described by Mella, Guo, and Hung (Plastic and Reconstructive Surgery — Global Open 2017). A surface-marking guide to the position of the spiralling bundle, useful in incision planning for limited fasciectomy.
-
Microvascular anastomosis
Joining of small blood vessels (typically less than 3 mm) under an operating microscope using sutures finer than a human hair.
-
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.
N
-
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.
-
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.
-
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.
-
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. Combined with paracetamol, supported by strong evidence in the 2024 AAOS guideline as the routine post-operative analgesic regimen for carpal tunnel release.
O
-
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.
-
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.
P
-
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.
-
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.
-
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.
-
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.
-
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).
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
R
-
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.
-
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.
-
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.
-
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.
-
Replantation
Reattachment of a part of the body that has been completely separated, with restoration of its own blood circulation through microvascular anastomosis.
-
Retrovascular cord
Pathological cord in Dupuytren's disease running deep (dorsal) to the digital neurovascular bundle. Typically contributes to proximal interphalangeal joint contracture and is the cord most commonly missed at primary surgery, identified by deliberate dorsal exploration of the bundle after the volar cords are excised.
-
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.
S
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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.
-
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 6–11 mm distal to Kaplan's cardinal line — the practical reason a carpal tunnel release incision stops well proximal to that line.
-
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.
-
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.
T
-
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.
-
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.
-
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.
-
Tinel sign
Tapping over a peripheral nerve elicits paraesthesia in its sensory distribution; described by Jules Tinel in 1915 in the context of regenerating peripheral nerves. Positive over the median nerve at the wrist supports a diagnosis of carpal tunnel syndrome.
-
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.
-
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.
-
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.
-
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.
-
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.
U
-
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.
-
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.
-
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.
V
-
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.
-
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.
-
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.
-
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.
-
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.