Specifically, it refers to the bony prominence you feel at the back of your elbow, which is formed by the olecranon process of the ulna.

Here's a breakdown:

* Olecranon: The bony projection at the back of the elbow, part of the ulna bone.

* Ulna: One of the two bones in the forearm (the other is the radius).

* Posterior: Refers to the back side of the body.

You can easily find the olecranal region by feeling for the bony bump on the back of your elbow when you extend your arm.