01 / Location & anatomical relationships
On the little-finger side of the forearm when the palm faces forward.
02 / Structure & organization
The olecranon and coronoid process frame the proximal trochlear notch that articulates with the humerus. The distal ulna is smaller and separated from the carpal bones by an articular disc.
03 / Function
Its upper end forms the bony point of your elbow.
04 / Mechanism
Its upper end hooks around part of the humerus, forming much of the elbow hinge. It gives the forearm a stable framework while the radius rotates. Muscles and connective tissues link the two bones.
Part of a bigger picture
The ulna belongs in our bones & movement collection. Explore the nearby parts to see how this area of the body fits together.
Explore bones & movement →FOR DEEPER STUDY
Connect structure with function
The ulna contributes strongly to elbow stability. Its relationship to the radius permits rotation while maintaining a stable connection between upper arm and hand.
Check your understanding
Locate the ulna in relation to its neighbors. Explain how the structural features described above support its function, then distinguish it from a nearby structure with a different role.
Keep learning
Continue with OpenStax Anatomy and Physiology for system-level study. This atlas is educational and has not undergone independent medical peer review.