The anteromedial surface of the humeral shaft contains

a portion of the bicipital groove proximally. The tendon of

the latissimus dorsi inserts into or along the medial crest of

the intertubercular groove in the area just distal to that traversed by the bicipital tendon. Distal and medial to this area

near the medial border, is the insertion area of the teres

major. In the midportion of the anteromedial shaft, near

the medial border of the humerus is the insertion area of the

coracobrachialis. In the distal portion of the anteromedial

surface of the humerus, the bone is flat and smooth, and

provides for the large origin of the brachialis muscle.

The dorsal surface of the humerus slightly rotates from

proximal to distal, so that the proximal portion is directed

slightly medially, and the distal portion is directed posteriorly and slightly laterally. The surface of the posterior surface of the humerus is nearly completely covered by the lateral and medial heads of the triceps brachii. The lateral head

arises from the proximal portion, on the lateral half of the

bone, just lateral to the radial sulcus. The origin of the

medial head of the triceps begins on the proximal third of

the posterior surface of the humerus, along the medial border of the bone and the medial distal border of the radial

sulcus. This large origin area extends the length of the posterior humerus, covering the major portion of the posterior

half of the humerus. The triceps origin extends distally to

end as far as distal as the posterior portion of the lateral epicondyle, just proximal to the origin of the anconeus muscle.

The medial and lateral borders run the entire length of

the humerus. The medial border of the humerus extends

from the lesser tuberosity to the medial epicondyle. The

proximal third of the medial border consists of a prominent

crest, the crest of the lesser tuberosity. The crest of the lesser

tuberosity provides the insertion area of the tendon of the

teres major. More distally, in the mid-portion of the shaft

and located on the medial border is a rough impression for

the insertion of the coracobrachialis. Distal to this area is

the entrance of the nutrient canal into the humerus. A second nutrient canal may exist at the starting point of the

1 Skeletal Anatomy 23