Wrist Joint

The radiocarpal joint and the midcarpal joint create the wrist. The radiocarpal joint consists of the distal end of the radius and the radioulnar disk proximally and the scaphoid, lunate, and triquetrum distally. The radiocarpal joint and the midcarpal joint create the wrist. The radiocarpal joint consists of the distal end of the radius and the radioulnar disk proximally and the scaphoid, lunate, and triquetrum distally. The midcarpal joints occur beween the two rows of carpal bones and contribute to wrist motion. Their shape is irregular and they are classified as plane joints. The midcarpal joints occur beween the two rows of carpal bones and contribute to wrist motion. Their shape is irregular and they are classified as plane joints. The carpometacarpal (CMC) joints occur beween the distal row of carpal bones and the proximal end of the metacarpal bones. The carpometacarpal (CMC) joints occur beween the distal row of carpal bones and the proximal end of the metacarpal bones.

Joint motions Flexion Flexion Neutral position Neutral position Extension Extension Ulnar deviation Ulnar deviation Radial deviation Radial deviation

Bones and Landmarks Starting on the thumb-side of the prximal row are the scaphoid, lunate, triquetrum, and pisiform. In the distal row, lateral to medial, are the trapezium, trapezoid, capitate, and hamate. Starting on the thumb-side of the prximal row are the scaphoid, lunate, triquetrum, and pisiform. In the distal row, lateral to medial, are the trapezium, trapezoid, capitate, and hamate.

Muscles of the Wrist Anterior: Anterior: –Flexor carpi ulnaris –Flexor carpi radialis –Palmaris longus Posterior: Posterior: –Extensor carpi radialis longus –Extensor carpi radialis brevis –Extensor carpi ulnaris

Flexor Carpi Ulnaris

O: Medial epicondyle of humerus O: Medial epicondyle of humerus I: Pisiform and base of fifth metacarpal I: Pisiform and base of fifth metacarpal A: Wrist flexion, ulnar deviation A: Wrist flexion, ulnar deviation N: Ulnar nerve (C8, T1) N: Ulnar nerve (C8, T1)

Flexor Carpi Radialis

O: Medial epicondyle of the humerus O: Medial epicondyle of the humerus I: Base of second and third metacarpals I: Base of second and third metacarpals A: Wrist flexion, radial deviation A: Wrist flexion, radial deviation N: Median nerve (C6, C7) N: Median nerve (C6, C7)

Palmaris Longus

O: Medial epicondyle of humerus O: Medial epicondyle of humerus I: Palmar fascia I: Palmar fascia A: Assistive in wrist flexion A: Assistive in wrist flexion N: Median nerve (C6, C7) N: Median nerve (C6, C7)

Extensor Carpi Radialis Longus

O: Supracondylar ridge of humerus O: Supracondylar ridge of humerus I: Base of second metacarpal I: Base of second metacarpal A: Wrist extension, radial deviation A: Wrist extension, radial deviation N: Radial nerve (C6, C7) N: Radial nerve (C6, C7)

Extensor Carpi Radialis Brevis

O: Lateral epicondyle of humerus O: Lateral epicondyle of humerus I: Base of third metacarpal I: Base of third metacarpal A: Wrist extension A: Wrist extension N: Radial nerve (C6, C7) N: Radial nerve (C6, C7)

Extensor Carpi Ulnaris

O: Lateral epicondyle of humerus O: Lateral epicondyle of humerus I: Base of fifth metacarpal I: Base of fifth metacarpal A: Wrist extension, ulnar deviation A: Wrist extension, ulnar deviation N: Radial nerve (C6, C7) N: Radial nerve (C6, C7)