8. The Hand.pdf

TOPIC 8: THE HAND The hand Carpometacarpal (CMC) Intermetacarpal Metacarpal-phalangeal Interpharangeal Carpometacarpal joint Distal row of carpal bones and the proximal bases of the five metacarpal bones Allows the concavity of the palm to fit around many objects Capsule...

TOPIC 8: THE HAND The hand Carpometacarpal (CMC) Intermetacarpal Metacarpal-phalangeal Interpharangeal Carpometacarpal joint Distal row of carpal bones and the proximal bases of the five metacarpal bones Allows the concavity of the palm to fit around many objects Capsule and ligaments (dorsal, palmar, interosseous) Plane joints: sling gliding, except: First metacarpal joint or Trapeziometacarpal Trapeziometacarpal joint Saddle joint: 2 main axis (flex/ext, ABD/ADD +oppoosition) Between: Trapezium and Metacarpal 1 Important function: Grasp, grip, hold, manipulate.. Close packed position: full position Osteokinematics Arthrokinematics Abduction/Adduction: convex rule (1MC is CONVEX, Trapezium is CONCAVE) Flexion/ Extension: concave rule (1MC is CONCAVE, Trapezium is CONVEX) Trapeziometacarpal joint stability High stress loads, particularly during pinch, grasp maneuvers. Capsule laxity: wide ROM Ligaments/ Tendons stability 2. Intermetacarpal joints Between the bases of second to fifth metacarpal bones. Connected by: The dorsal and velar ligaments pass transversely from one metacarpal to another, on the dorsal and velar surfaces. Reinforcement of the Carpometacarpal joints 3. Metacarpophalangeal joints Between the metacarpal bones and the proximal phalanges of the fingers Condyloid joints # Convex metacarpal head - concave base of the first phalanx * Arthrokinematics: Concave rule Stability: -Palmar and collateral ligaments -Flexors and extensors muscles Metacarpophalangeal arthrokinematics 4. Interphalangeal joints Between the phalanges of the fingers. Provide flexion towards the palm of the hand. Hinge joints. Flexion/extension Stability: -Palmar and collateral ligaments -Flexors and extensors muscles # Concave rule Interphalangeal arthrokinematics