Forearm Muscles (PDF)

Front of forearm Dr Sapna Muscles of the front of the forearm Superficial layer: Arranged from lateral to medial side : 1. Pronator teres. 2. Flexor carpi radialis 3. Palmaris longus. 4. Flexor carpi ulnaris. Intermediate layer Flexor digitorum superficialis  Deep layer Flexor...

Front of forearm Dr Sapna Muscles of the front of the forearm Superficial layer: Arranged from lateral to medial side : 1. Pronator teres. 2. Flexor carpi radialis 3. Palmaris longus. 4. Flexor carpi ulnaris. Intermediate layer Flexor digitorum superficialis  Deep layer Flexor policis longus Flexor digitorum profundus Pronator quadratus Muscles of the front of the forearm-Superficial muscles Origin : common flexor origin- medial condyle of the humerus – for all the superficial muscles Pronator teres Nerve supply: Median nerve Action: Pronation  Flexor carpi radialis Nerve supply: Median nerve Action: Flexes and abducts the wrist joint Palmaris longus Nerve supply: Median nerve Action: Flexion of the wrist joint. Makes the skin tense during hand grip  Flexor carpi ulnaris Nerve supply: Ulnar nerve Action: Flexes and adducts the wrist joint Intermediate layer Flexor digitorum superficialis Nerve supply: Median nerve Action: Flexes proximal inter- phalangeal joints of the medial 4 fingers Deep muscles of the forearm Flexor digitorum profundus Nerve supply: Lateral ½ by anterior interosseous branch of median nerve Medial ½ by ulnar nerve Action: Flexes distal inter- phalangeal joints, middle interphalangeal joints, metacarpo - phalangeal joints of the medial 4 fingers and flexes the wrist joint. Deep muscles of the forearm Flexor policis longus Nerve supply: Anterior interosseous of median nerve Action: Flexes inter- phalangeal joint; and metacarpo-phalangeal joint of the thumb. Deep muscles of the forearm Pronator quadratus Nerve supply: Anterior interosseous branch of median nerve. Action: Pronation Flexor retinaculum Band of fibrous connective tissue anterior to the carpal bones(palmar surface) Prevents the flexor tendons from popping out Attachments: Medially :pisiform & hook of hamate Laterally : scaphoid & trapezium  Carpal tunnel: median nerve if compressed leads to carpal tunnel syndrome Back of forearm Dr Sapna  Superficial Layer Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minim Extensor carpi ulnaris Anconeus  Deep layer Supinator Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis  Origin: (common extensor origin) Front of lateral epicondyle of humerus Nerve supply Extensor carpi radialis Brachioradialis brevis Extensor carpi radialis Extensor carpi ulnaris longus Extensor digitorum Anconaeus Extensor digiti minimi All deep muscles Radial Deep branch nerve Radial nerve (posterior interosseous nerve)  Elbow joint and radioulnar joints Dr Sapna Shevade Objectives Classify elbow and radioulnar joints Name the articulating bones Name the ligaments of the joint Name the movements of the joint Name the muscles that bring about the movements  Elbow joint Hinge variety of synovial joint Articulating bones: Humero - radial Humero - ulnar Ligaments of elbow joint Capsule : attached to the margins of articular surfaces Synovial membrane lines the fibrous capsule Intra-articualr fossa: Coronoid fossa Radial fossa Olecranon fossa  Annular ligament: holds the head of the radius to the ulna Radial collateral ligament : extends from lateral epicondyle to lateral part of annular ligament surrounding humerus  Ulnar collateral ligament: extends from medial epicondyle Consists of three parts: anterior, posterior and oblique  Movements of elbow joint Flexion Extension Flexion : biceps brachii, Triceps brachii bracialis, brachioradialis Radioulnar joints Superior radioulnar joint : head of the radius and radial notch of ulna Synovial pivot joint Inferior radioulnar joint: ulnar notch of radius and ulnar head Synovial pivot joint Radioulnar joints Middle radioulnar joint: interosseous membrane connects the shafts of radius and ulna. Fibers of the membrane run downwards and medially  Ligaments of superior radioulnar joint Annular ligament: Head of radius rotates within the annular ring Attached to the margins of the radial notch Quadrate ligament : Extends from the neck of the radius to the lower margin of radial notch Oblique cord Ligaments of inferior radioulnar joint Capsule surrounds the joint Articular disc : has apex and a base Apex : Attached to the base of styloid process of ulna Base : attached to the lower margin of ulnar notch Movements of radioulnar joint Supination Pronation Supinator Pronator teres Biceps brachii (strong Pronator quadratus supinator in midprone position)