Wrist Joints and Movement of the Hand Flashcards
What type of joint is the wrist joint (radiocarpal joint)?
The wrist joint (radiocarpal joint) is a synovial ellipsoid (condyloid) joint.
What bones articulate to form the wrist joint?
The wrist joint is formed by the distal end of the radius and the articular disc of the ulna articulating with the scaphoid, lunate, and triquetrum bones.
What are the main ligaments stabilizing the wrist joint?
The main ligaments stabilizing the wrist joint are the palmar radiocarpal, dorsal radiocarpal, ulnar collateral, and radial collateral ligaments.
What is the function of the palmar radiocarpal ligament?
The palmar radiocarpal ligament prevents excessive wrist extension and ensures the hand follows the forearm during supination.
What is the function of the dorsal radiocarpal ligament?
The dorsal radiocarpal ligament prevents excessive wrist flexion and ensures the hand follows the forearm during pronation.
What is the role of the ulnar collateral ligament of the wrist?
The ulnar collateral ligament provides medial stability and limits excessive radial deviation.
What is the role of the radial collateral ligament of the wrist?
The radial collateral ligament provides lateral stability and limits excessive ulnar deviation.
What movements occur at the wrist joint?
The wrist joint allows flexion, extension, abduction (radial deviation), and adduction (ulnar deviation).
What muscles are primarily responsible for wrist flexion?
Wrist flexion is primarily performed by the flexor carpi radialis, flexor carpi ulnaris, and palmaris longus.
What muscles are primarily responsible for wrist extension?
Wrist extension is primarily performed by the extensor carpi radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris.
What muscles contribute to wrist abduction (radial deviation)?
Wrist abduction (radial deviation) is performed by the flexor carpi radialis and extensor carpi radialis longus/brevis.
What muscles contribute to wrist adduction (ulnar deviation)?
Wrist adduction (ulnar deviation) is performed by the flexor carpi ulnaris and extensor carpi ulnaris.
What are the articulations of the midcarpal joint?
The midcarpal joint is the articulation between the proximal and distal rows of carpal bones, excluding the pisiform.
What type of joint is the midcarpal joint, and what movements occur there?
The midcarpal joint is a functional hinge joint that contributes to wrist flexion and extension.
What is the significance of the triangular fibrocartilage complex (TFCC) in wrist stability?
The triangular fibrocartilage complex (TFCC) stabilizes the distal radioulnar joint and absorbs compressive forces at the wrist.
What structures pass through the carpal tunnel?
The carpal tunnel contains the median nerve, flexor digitorum superficialis tendons, flexor digitorum profundus tendons, and flexor pollicis longus tendon.
What is the clinical significance of carpal tunnel syndrome?
Carpal tunnel syndrome results from median nerve compression within the carpal tunnel, leading to numbness, tingling, and weakness in the hand.
What are the articulations of the carpometacarpal joints?
The carpometacarpal joints articulate between the distal row of carpal bones and the bases of the metacarpals.
What type of joint is the first carpometacarpal joint, and what movements does it allow?
The first carpometacarpal joint (thumb) is a saddle joint that allows flexion, extension, abduction, adduction, opposition, and reposition.
What is opposition of the thumb, and which muscles are responsible for it?
Opposition of the thumb is a movement combining flexion, abduction, and medial rotation, primarily performed by the opponens pollicis muscle.
What movements occur at the metacarpophalangeal (MCP) joints?
The metacarpophalangeal (MCP) joints allow flexion, extension, abduction, adduction, and circumduction.
What ligaments stabilize the MCP joints?
The MCP joints are stabilized by collateral ligaments and the palmar (volar) plates.
What movements occur at the interphalangeal (IP) joints?
The interphalangeal (IP) joints allow flexion and extension only.
What ligaments support the interphalangeal joints?
The interphalangeal joints are supported by collateral ligaments and volar plates.
What is the function of the extensor retinaculum of the wrist?
The extensor retinaculum holds the extensor tendons in place and prevents bowstringing during wrist extension.
What is the function of the flexor retinaculum of the wrist?
The flexor retinaculum stabilizes the flexor tendons and forms the roof of the carpal tunnel.
What is the role of the intrinsic hand muscles in fine motor control?
The intrinsic hand muscles control fine movements such as grip precision and finger coordination.
What is the function of the lumbricals in hand movement?
The lumbricals flex the MCP joints and extend the IP joints, facilitating delicate finger movements.
What are the functions of the palmar and dorsal interossei muscles?
The palmar interossei adduct the fingers (PAD), while the dorsal interossei abduct the fingers (DAB).
What nerve injuries can affect wrist and hand movement?
Median nerve injury affects thumb opposition, ulnar nerve injury affects finger abduction and adduction, and radial nerve injury impairs wrist extension.
