Figs. 6-11 and 6-12. The right humerus. On the left side are the anatomical landmarks from the anterior and posterior side. In the lowermost cross section, capital letters indicate the surfaces of the humerus, while the small letters indicate the borders. The figures to the right show muscular and ligamentous attachments and the relationship of nerves. Note that the insertion of the deltoid muscle is fused with the pectoralis major in front and with the lateral head of the triceps behind. The portion of the humerus related to the axillary nerve is the surgical neck and is liable to fracture. Click for high resolution image.