Wrist and Hand Complex Vocabulary Flashcards

Vocabulary practice flashcards generated from lecture material covering anatomy, biomechanics, osteokinematics, arthrokinematics, and functional actions of the wrist and hand complex.

Radiocarpal Joint

The proximal articulation of the wrist complex formed between the distal radius and the proximal row of carpal bones (scaphoid, lunate, triquetrum, and pisiform).

Midcarpal Joint

The articulation situated between the proximal row and distal row of carpal bones (trapezium, trapezoid, capitate, and hamate).

Ulnar Tilt

The $25^\bullet$ tilt of the distal radius toward the ulna that permits a greater range of ulnar deviation compared to radial deviation.

Palmar Tilt

The $10^\bullet$ angle of the distal radius toward the volar surface that allows for greater wrist flexion than extension.

Scaphoid

The most frequently fractured carpal bone, highly susceptible to fall on outstretched hand (FOOSH) injuries and prone to avascular necrosis (AVN).

Kienbock's Disease

A condition defined by avascular necrosis (AVN) of the lunate bone, which can originate from traumatic or atraumatic etiologies.

Extrinsic Wrist Ligaments

Ligaments of the wrist complex that have an proximal attachment on the radius or ulna and distal attachments within the carpals.

Intrinsic Wrist Ligaments

Wrist ligaments with both proximal and distal attachments contained entirely inside the carpal region.

Triangular Fibrocartilage Complex (TFCC)

A fibrocartilaginous structure that functions primarily to stabilize the distal radioulnar joint and bind the ulna to adjacent carpal bones.

Maximal Grip Strength Position

Wrist alignment at approximately $30^\bullet$ of extension where primary wrist extensors prevent unwanted wrist flexion to optimize the length-tension relationship of extrinsic finger flexors.

Physiological Cross-Sectional Area (PCSA) of Wrist Flexors

The structural factor enabling wrist flexors to generate roughly $70\%$ greater torque than wrist extensors, with FDS and FDP providing approximately $2/3$ of total flexor PCSA.

Palmar Arches

The natural concavity across the palmar surface of the relaxed hand that enables the hand to conform to objects of varying dimensions and shapes.

Carpal Tunnel

An anatomical tunnel bounded by the palmar concavity of the carpals and covered by the transverse carpal ligament, accommodating the median nerve and digital flexor tendons.

Thumb Carpometacarpal (CMC) Joint

A 2 DOF saddle joint between the trapezium and 1st metacarpal that permits flexion/extension, abduction/adduction, and opposition/reposition.

Skier's Thumb

An acute or repetitive trauma injury to the ulnar collateral ligament (UCL) of the thumb metacarpophalangeal (MCP) joint, also termed Gamekeeper's thumb.

Flexor Pulleys

Fibrous annular and cruciate bands that secure flexor tendons against phalanx bones to maintain a steady moment arm and ensure efficient tendon gliding.

Bowstring Phenomenon

An abnormal anterior displacement of digital flexor tendons away from the joint axis during muscle activation caused by a tear or rupture in an annular pulley (such as A3).

Extensor Mechanism

A continuous fibrous sheet along the dorsal side of digits 2-5 that integrates extensor tendons to balance force distribution across MCP, PIP, and DIP joints.

Tenodesis Action

A functional grasping technique for individuals with C8 spinal cord injury where active wrist extension (C6 myotome) induces passive insufficiency in extrinsic finger flexors, flexing the digits.

Anatomic Snuffbox

A triangular depression located on the radial aspect of the wrist demarcated by the tendons of Extensor Pollicis Longus, Extensor Pollicis Brevis, and Abductor Pollicis Longus.

Power Grips

Grasp classifications focused on force production and gross manipulation, encompassing cylindrical, spherical, and hook grips.

Precision Grips

Grasp classifications designed for high accuracy and fine motor dexterity, encompassing pinch, tripod, and lumbrical grips.