ATLAS OF HUMAN ANATOMY - G.L. Bilich - 2014

Muscular System

MUSCLES AND FASCIA OF THE UPPER LIMB

Anteriorly, the upper limb is separated from the trunk by an imaginary line running along the deltopectoral groove; posteriorly, by the posterior deltoid groove; and inferiorly, by a line connecting the lower border of the pectoralis major anteriorly with the latissimus dorsi and teres major posteriorly. Several anatomical landmarks can be identified on the upper limb: the deltoid Muscle in the corresponding region, the biceps brachii on the anterior aspect of the arm, and the triceps brachii on its posterior aspect. The medial and lateral epicondyles of the humerus can be palpated, as well as the olecranon of the ulna posteriorly. In the wrist area, the styloid processes of the radius and ulna are clearly defined. On the hand, the thenar eminence (ball of the thumb) and the hypothenar eminence (ball of the little finger) are distinctly visible.

As an organ of labor, the hand performs numerous and diverse movements driven by a multitude of Muscles. Many of these originate on the BONES OF THE trunk—the Ribs, Sternum, and spine—and insert into the bones of the Pectoral Girdle and the humerus (described above).

Some Muscles of the Upper Limb originate on the bones of the pectoral girdle (clavicle, scapula) and insert into the humerus and the bones of the forearm (radius, ulna). Other upper limb muscles originate on the bones of the Free part of the limb (bones of the arm, forearm, and hand), span one or more joints, and insert into other bones of the limb (Fig. 303, 304, 305). The muscles of the upper limb are subdivided into the muscles of the pectoral girdle and the Muscles of the Free Upper Limb (Table 46).