Shoulderarmforearmhand

Shoulderarmforearmhand refers to the upper limb from the shoulder through the arm, forearm, and hand. It encompasses the bones, joints, muscles, nerves, and vessels that enable range of motion, strength, and fine motor control used in daily activities and skilled tasks.

The shoulder region includes the scapula, clavicle, and humerus, forming the shoulder girdle and ball-and-socket glenohumeral joint. The joint is stabilized by the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, subscapularis), the deltoid, and supporting ligaments. The shoulder allows extensive mobility, including rotation, abduction, and anteversion, but is also prone to instability and impingement injuries. Nerves such as the axillary and suprascapular nerves and the subclavian or axillary blood vessels run in this area.

The upper arm contains the humerus and the elbow joint complex, including the humeroulnar and humeroradial joints. The anterior compartment houses the biceps brachii, brachialis, and coracobrachialis; the posterior compartment contains the triceps brachii. Innervation is primarily by the musculocutaneous nerve in the anterior compartment and the radial nerve in the posterior, with the brachial artery supplying arterial blood to the arm.

The forearm contains two parallel bones, the radius and ulna, connected by an interosseous membrane. It is divided into flexor/pronator (anterior) and extensor/supinator (posterior) compartments. Key nerves include the median, ulnar, and radial nerves, which provide motor and sensory function to the forearm and hand. The radioulnar joints enable forearm rotation, while the wrist joints connect the forearm to the hand.

The hand comprises the carpal bones of the wrist, metacarpals, and phalanges. Intrinsic and extrinsic muscles coordinate grip, precision pinch, and fine motor tasks. The median, ulnar, and radial nerves innervate the hand, supplying sensation and motor control to the palm, fingers, and thumb.

Common clinical concerns involve shoulder impingement, rotator cuff tears, elbow and wrist tendinopathies, nerve compression syndromes, and fractures affecting any segment of this region.