Wrist PDF

TOPIC 7: THE WRIST COMPLEX Functions Control the multi-articular muscles of the hand Fine adjustment of the grip 2 degree of freedom -Radial/ulnar deviation -Flexion/Extension Complex Distal radio-ulna joint Radiocarpal joint Midcarpal articulation 1. The distal radio...

TOPIC 7: THE WRIST COMPLEX Functions Control the multi-articular muscles of the hand Fine adjustment of the grip 2 degree of freedom -Radial/ulnar deviation -Flexion/Extension Complex Distal radio-ulna joint Radiocarpal joint Midcarpal articulation 1. The distal radioulnar joint Pivot joint Concave rule: Radius (concave) moves Function: Forearm pronosupination Arthrokinematic gliding component: -Pronation: Palmar Rolling and Gliding -Supination: Dorsal Rolling and Gliding 2. The radiocarpal joint Proximally: radius & radioulnar disk (distal radius is concave) Distally: 3 bones in the proximal carpal row: scaphoid, lunate, and triquetrum. (Ellipsoid joint) 3. Intercarpal/ Midcarpal Joint Compound joint: three or more articulation surfaces Two single functional units: -Proximal row: scaphoid-lunate-triquetrum (mobile) -Distal row: trapezium-trapezoid-capitate-hamate (immobile) Wrist osteokinematics Open kinematic chain (flexion/extension) Movement of the carpal bones on top of the radius. Proximal and distal rows move. Convex rule (roll &glide occur in opposite directions!!!) Radiocarpal (red arrows) Midcarpal/ intercarpal (white arrows) FLEXION: Roll anterior and glide posterior EXTENSION: Roll posterior and glide anterior Open kinematic chain (radio/ulnar deviation) Movement of the carpal bones on top of the radius Proximal and distal rows move Convex rule (roll & glide occur in opposite directions !!!) Radiocarpal (red arrows) Midcarpal/ intercarpal (white arrows) RADIAL DEVIATION: Roll radial/ glide ulnar ULNAR DEVIATION: Roll ulnar/ glide radial Wrist arthrokinematics Convex rule Radiocarpal Midcarpal/ intercarpal Wrist Stability Static: Capsule attaches to the radius, ulna and the proximal row of the carpal bones. Ligaments -Radiocarpal (Palmar and dorsal ligaments, radial and ulnar collateral ligaments) -Intercarpal: Palmar and dorsal -Triangular fibrocartilage complex Dynamic: Palmar & dorsal musculature of the wrist Passive ligaments limits to osteokinematics # The triangular fibrocartilage complex ( TFCC) Load bearing structure located on the medial aspect of the wrist region between lunate, triquetrum, and ulnar head. Functions as a major stabilizer of both radiocarpal and ulnocarpal joints. Facilitates the complex movements at the wrist joint. Passive ligament limits to osteokinematics Scapholunate ligament Connects the scaphoid bone to the lunate bone in the wrist and helps stabilize the two bones, maintaining the alignment of the carpal bones helping with the overall stability of the wrist joint. Injuries to this ligament can occur due to: falls onto an outstretched hand, sudden impacts or repetitive stress over time. It can lead to instability of the wrist joint, which may result in pain, weakness, and limited range of motion.  - & - - - - - 1.B, 2.D, 3.A, 4.A, 5.C, 6.A, 7.D e &