21 The lateral muscle of forearm ........

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1. Muscles of the Lateral Fascial Compartment of the Forearm Aizaz Demonstrator Surgical KMU-IPMS Peshawar

2. Brachioradialis Origin: Lateral supracondylar ridge of humerus Insertion: Base of styloid process of radius Nerve Supply: Radial nerve Action: Flexes forearm at elbow joint; rotates forearm to the midprone position

3. Extensor carpi radialis longus Origin: Lateral supracondylar ridge of humerus Insertion: Posterior surface of base of second metacarpal bone Nerve Supply: Radial nerve Action: Extends and abducts hand at wrist joint

4. Cubital Fossa The  cubital (anticubital) fossa  is a triangular-shaped depression over the anterior aspect of the elbow joint Boundaries: The fossa is triangular and consist of three borders , a roof and floor Lateral Border: Brachioradialis muscle Medial Border: Pronator teres muscle Superior Border(Base): Imaginary line drawn between the two epicondyles of the humerus. Floor: Supinator muscle laterally and the brachialis muscle medially Roof: Skin and fascia and is reinforced by the bicipital aponeurosis

5. Cubital Fossa The cubital fossa contains the following structures , enumerated from the medial to the lateral side: Median nerve Bifurcation of the brachial artery into the ulnar and radial arteries Tendon of the biceps muscle Radial nerve and its deep branch The supratrochlear lymph node lies in the superficial fascia over the upper part of the fossa.

6. Flexor retinaculum The flexor retinaculum (transverse carpal ligament, or anterior annular ligament) is a fibrous band on the palmar side of the hand near the wrist. It arches over the carpal bones of the hands, covering them and forming the carpal tunnel The flexor retinaculum is a thickening of deep fascia that holds the long flexor tendons in position at the wrist . It stretches across the front of the wrist and converts the concave anterior surface of the hand into an osteofascial tunnel, the carpal tunnel , for the passage of the median nerve and the flexor tendons of the thumb and fingers

7. Flexor retinaculum Thick connective tissue which forms the roof of the carpal tunnel. Turns the carpal arch into the carpal tunnel by bridging the space between the medial and lateral parts of the arch. Spans between the hook of hamate and pisiform (medially) to the tubercle of scaphoid and trapezium (laterally)

8. Extensor Retinaculum The extensor retinaculum is a thickening of deep fascia that stretches across the back of the wrist and holds the long extensor tendons in position. It converts the grooves on the posterior surface of the distal ends of the radius and ulna into six separate tunnels for the passage of the long extensor tendons. Each tunnel is lined internally by a synovial sheath and separated from one another by fibrous septa The retinaculum is attached medially to the pisiform bone and the hook of the hamate and laterally to the distal end of the radius . The upper and lower borders of the retinaculum are continuous with the deep fascia of the forearm and hand , respectively.

9. Carpal Tunnel The carpal tunnel is a narrow passageway found on the anterior portion of the wrist. It serves as the entrance to the palm for several tendons and the median nerve. Tendons The tendon of flexor pollicis longus Four tendons of flexor digitorum profundus Four tendons of flexor digitorum superficialis The 8 tendons of the flexor digitorum profundus and flexor digitorum superficialis are surrounded by a single synovial sheath . The tendon of flexor pollicis longus is surrounded by its own synovial sheath . These sheaths allow free movement of the tendons The median nerve passes beneath the flexor retinaculum in a restricted space between the flexor digitorum superficialis and the flexor carpi radialis muscles.