Which structure is identified by the letter B in the image of the elbow?

The olecranon process is a prominent bony structure located at the proximal end of the ulna, specifically forming the point of the elbow. It serves as an important anatomical landmark and is directly involved in the flexion and extension movements of the arm at the elbow joint.

Identified as a key structure in the elbow, the olecranon process acts as a lever arm for the triceps muscle, which is crucial for extending the forearm. Its shape allows it to fit snugly into the humeral notch during elbow movement, facilitating a smooth range of motion. Understanding the location and function of the olecranon process is essential in evaluating elbow injuries and relating them to the specific movement patterns of the upper limb.

In contrast, while the radius and ulna are the two primary bones of the forearm, the radius is primarily located on the lateral side of the forearm, and the ulna is on the medial side, with the olecranon process being a specific part of the ulna. The coronoid process, another structure associated with the ulna, is located anteriorly at the distal end and does not play the same foundational role in the elbow's structure as the olecranon.