Muscles of the upper extremity include the muscles of the shoulder girdle, the muscles of the upper arm, the muscles of the forearm and the muscles of the hand. The use of the upper limb is essential for everyday living and it is a highly mobile part of the body that has been adapted to carry out many movements, from fine movements such as writing and grasping objects to lifting, throwing etc.
The subscapularis muscle, which is innervated by the subscapular nerve, and the supraspinatus and infraspinatus muscles, which are innervated by the suprascapular nerve, are three of four muscles that make up the rotator cuff muscles. These muscles have their origin on the scapula and insert on the humerus. The deltoid muscle functions to move and stabilize the shoulder joint, and it is innervated by a branch of the brachial plexus, the axillary nerve.
The coracobrachialis muscle, along with the biceps brachii and the brachialis muscle are innervated by the musculocutaneous nerve. Muscles innervated by the radial nerve include the triceps brachii, musculus supinator, extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris, extensor pollicis longus and extensor pollicis brevis.
Pronator teres, pronator quadratus andsome of the flexor muscles of the forearm, flexor carpi radialis, part of flexor digitorum profundus, flexor digitorum profundus, and the first and second lumbricals are innervated by the median nerve.
Part of flexor digitorum profundus, adductor pollicis, abductor digiti minimi, flexor pollicis brevis, palmaris brevis, the third and fourth lumbricals and the dorsal and palmar interossei muscles are all innervated by the ulnar nerve.
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