upperextremity

The upper extremity, also called the upper limb, comprises the region from the shoulder girdle to the hand. It is specialized for mobility and manipulation, enabling gross motor actions and fine dexterity. It includes the pectoral girdle, the arm, forearm, and hand.

The pectoral girdle consists of the scapula and clavicle. The arm contains the humerus, the forearm contains the radius and ulna, and the hand contains the carpal bones, the metacarpals, and the phalanges. The major joints are the glenohumeral (shoulder), acromioclavicular, sternoclavicular at the shoulder complex; the elbow (humero-ulnar and humero-radial joints); the proximal and distal radioulnar joints; and the wrist (radiocarpal) and the hand joints (carpometacarpal, metacarpophalangeal, and interphalangeal joints).

Muscle groups include the shoulder girdle muscles (deltoid, trapezius, serratus anterior) and the rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis), along with arm muscles (biceps brachii, triceps brachii), forearm flexors and extensors, and intrinsic hand muscles. Innervation is via the brachial plexus, giving rise to the axillary, musculocutaneous, radial, median, and ulnar nerves. Blood supply comes mainly from the subclavian, axillary, and brachial arteries, with radial and ulnar arteries supplying the distal segments.

The upper extremity supports skilled tasks such as grasping, manipulating objects, and tactile exploration. Common clinical issues include rotator cuff injuries, shoulder dislocations, clavicle fractures, elbow disorders, carpal tunnel syndrome, and peripheral nerve injuries.