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Hand Bones. Pisiform Triquetrum Lunate Scaphoid Trapezium Trapezoid Capitate Hamate. Hand Bones. Hand joints. Carpometacarpal joint(s) – (CMC) Metacarpophalangeal joints – (MCP) Interphalangeal joints (proximal & distal) 1 st digit (IP) 2-5 digits (PIP and DIP).
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Hand Bones • Pisiform • Triquetrum • Lunate • Scaphoid • Trapezium • Trapezoid • Capitate • Hamate
Hand joints • Carpometacarpal joint(s) – (CMC) • Metacarpophalangeal joints – (MCP) • Interphalangeal joints (proximal & distal) • 1st digit (IP) • 2-5 digits (PIP and DIP)
Movements of the Wrist • flexion and extension • adduction (ulnar deviation) and abduction (radial deviation)
Tips for the forearm muscles • Flexors and Palmaris longus (medial epicondyle) *flexor digitorum profundus • Extensors (lateral epicondyle) • “carpi radialis” – radial deviation (abduction) • “carpi ulnaris” – ulnar deviation (adduction)
Flexor carpi radialisO: Medial epicondyle of humerusI: Base of second and third metacarpals, anterior (palmar surface)A: wrist flexion, abduction of wrist, weak elbow flexion, weak pronation of forearm
Palmaris longusO: Medial epicondyle of humerusI: Palmar aponeurosis of 2nd, 3rd, 4th, and 5th metacarpalA: Wrist flexion, weak elbow flexion
Flexor carpi ulnarisO: Medial epicondyle of humerus,posterior aspect of proximal ulnaI: Pisiform, hamate, and base of 5th metacarpal (palmar surface)A: wrist flexion, adduction of wrist, weak elbow flexion
Superficial Layer (Anterior Surface) • * Pronator teres (2nd) • Flexor carpi radialis (3rd) • Palmaris longus (4th) • Flexor carpi ulnaris (pinky)
Extensor carpi ulnarisO: Lateral epicondyle of humerus, middle two-fourths of posterior border of ulnaI: Base of 5th metacarpal (dorsal surface)A: wrist extension, wrist adduction, weak extension of elbow
Extensor digiti minimiO: Lateral epicondyle of humerusI: Base of middle and distal phalanxes of 5th phalangeA: Extension of little finger at MCP joint, weak wrist and elbow extension
Extensor digitorumO: Lateral epicondyle of humerusI: Four tendons to bases of middle and distal phalanges of four fingers (dorsal surface)A: Extension of 2nd, 3rd, 4th, and 5th phalanges at MCP joints, extension of wrist, weak extension of elbow
Extensor carpi radialis brevisO: Lateral epicondyle of humerusI: Base of 3rd metacarpal (dorsal surface)A: extension of wrist, abduction of wrist, *weak elbow extension
Extensor carpi radialis longusO: Lower third lateral supracondylar ridge and lateral epicondyle of humerusI: Base of 2nd metacarpal (dorsal surface)A: Extension of wrist, abduction of wrist, *weak elbow extensor, weak pronation
Superficial Layer (Posterior) • Extensor carpi ulnaris • Extensor digiti minimi • Extensor digitorum • Extensor carpi radialis brevis • Extensor carpi radialis longus • Brachioradialis*
Torque • Defined as “rotary” force • Torque is the product of linear force (F) and the force’s moment arm (d┴) T = Fd┴ T = F┴d • Torque is created when linear force acts away from the axis of rotation • Joint movements are rotational movements and thus are generated from torque
Levers • A lever is a rigid bar that rotates about an axis of rotation or fulcrum • Levers represent the interaction of muscle torque (from linear force (F)) and resistive torque (from linear resistive force (R)) • There are three different classes of levers (Class I, II, III)
Levers will emphasize two different functions depending on the location of F and R (length of moment arm) in relation to the fulcrum or axis of rotation. • Large torque production • Large ROM and speed • Class II levers will emphasize force or torque production • Class III levers will emphasize large ROM and speed (human body is comprised mostly of Class III levers)