Final answer:
The olecranon process is the part of the ulna that forms the bony tip of the elbow and serves as the point of articulation with the humerus.
Step-by-step explanation:
The part of the ulna that actually comprises our elbow is called the olecranon process. The olecranon process forms the bony tip of the elbow and is part of the upper extremity's structure. At the proximal end of the ulna, this process serves as the point of articulation with the humerus, facilitating elbow joint movement.