Olecranon fossa

Definition

The olecranon fossa is a deep, triangular depression located on the posterior aspect of the humerus, just above the trochlea. It accommodates the olecranon process of the ulna when the arm is fully extended.

Related terms

Humerus: The long bone in the upper arm that connects to the shoulder at one end and the elbow at the other.

Olecranon Process: A bony projection of the ulna at the elbow, which interlocks with the olecranon fossa during arm extension.

Trochlea: A grooved part of the humerus that articulates with one of the bones in the forearm (the ulna) to allow for elbow movement