Humerus Shaft
The humerus shaft is the section of the humerus bone that lies between its proximal and distal ends. This part of the bone is characterized by various muscle attachment sites. When examining a cross-section of the bone, it becomes apparent that the shaft is circular in shape towards the proximal end, but gradually becomes flatter towards the distal end. Positioned near the middle of the shaft is a rough surface called the deltoid tuberosity. This particular area functions as an attachment point for the deltoid muscle. Additionally, running along the back of the humerus is a shallow indentation known as the radial groove.
Unique Bony Landmarks at the Distal End
When examining the distal portion of the humerus, one can observe several distinct bony landmarks. These structures serve various functions and contribute to the overall structure of the bone.
The lateral supracondylar ridges, located at the borders of the humerus, possess rough surfaces that provide attachment points for muscles. Additionally, just below these ridges, there are two bony projections known as the lateral and medial epicondyles. The medial epicondyle, being larger and extending further, distinguishes itself from its lateral counterpart.
The trochlea and the capitulum, situated towards the center of the humerus, also contribute to the unique features of the distal end. Furthermore, three depressions can be identified in this region: the olecranon, radial, and coronoid fossae.