The mid-arm circumference was taken from the left arm from the mid-point between the tip of the acromion process and the olecranon process.
Proximally, the ulna has a bony process, the olecranon process, a hook-like structure that fits into the olecranon fossa of the humerus.
The compact layer is continued onto the back of the olecranon as a plate of close spongy bone with lamell parallel.
A second incision is made to expose the triceps insertion and the triceps is dissected from its insertion on the olecranon.
In the lower arm the robust ulna has a well-developed olecranon process.
It is directly inferior to the coronoid fossa anteriorly and to the olecranon fossa posteriorly.
They are usually subcutaneous especially over bony prominences such as the tip of the elbow or olecranon or over the finger knuckles.
The right ulna is small and slender, is missing an olecranon, and has a well-marked ridge.
