humeri

Humeri (singular humerus) are the two long bones of the upper arm. Each humerus runs from the shoulder girdle to the elbow, connecting the scapula to the forearm. The proximal end features the rounded head that articulates with the glenoid cavity of the scapula, the anatomical neck, and the greater and lesser tubercles for muscle attachments. The intertubercular groove houses the tendon of the long head of the biceps brachii. The shaft has a deltoid tuberosity on its lateral surface where the deltoid muscle attaches, and a radial groove on the posterior aspect for the radial nerve. The distal end forms two articulations: the capitulum with the head of the radius and the trochlea with the trochlear notch of the ulna. Medial and lateral epicondyles provide attachment sites for forearm muscles, and fossae such as the coronoid, olecranon, and radial fossae accommodate forearm flexion and extension.

The humeri are supplied by periosteal vessels from the brachial artery, and innervation is provided by nerves that run close to the bone, including the axillary nerve near the surgical neck and the radial nerve in the radial groove. Clinically, fractures of the proximal humerus or midshaft and dislocations around the shoulder are common; injury to the nerves near the bone is a consideration in trauma. In development, ossification centers appear in infancy with secondary centers at the proximal and distal ends during adolescence. The term humeri is the Latin plural form of humerus.