For descriptive osteology, the humerus can be described

in terms of the proximal end, the shaft (diaphysis or body),

and the distal end (Fig. 1.14; see Figs 1.11 to 1.13). The

proximal end consists of the head, anatomic neck, surgical

neck, and the greater and lesser tuberosities. The distal end

includes the capitulum, trochlea, and medial and lateral

condyles and epicondyles.

Proximal End of the Humerus

The head of the humerus forms nearly half of a sphere (see

Figs. 1.11 to 1.13). With the arm at the side of the body,

the humeral head is directed medially, superiorly, and

slightly posteriorly, thus facing the glenohumeral joint. The

entire smooth area, covered by hyaline cartilage, articulates

with the glenoid of the scapula.

The anatomic neck of the humerus denotes an obliquely

oriented margin or circumference line that extends along

and inferior to the articular portion of the head (see Figs.

1.11 and 1.12). In this area there is a groove that encircles

the articular portion. The groove is well delineated along

the inferior half. In the superior portion, the groove narrows to separate the head from the greater and lesser

18 Systems Anatomy