The olecranon fossa is a deep triangular depression on the posterior side of the humerus, superior to the trochlea. It provides space for the olecranon of the

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

during extension of the forearm.

Structure

The olecranon fossa is located on the posterior side of the distal humerus. The joint capsule of the

elbow The elbow is the region between the arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa (also called the chelidon, or the elbow pit), and the lateral and the m ...

attaches to the humerus just proximal to the olecranon fossa.

Function

The olecranon fossa provides space for the olecranon of the

during extension of the forearm, from which it gets its name.

Other animals

The olecranon fossa is present in various

mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), f ...

, including

dogs The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. ...

Additional images

File:Slide1bgbg.JPG, Elbow joint. Deep dissection. Posterior view. File:Slide2bgbg.JPG, Elbow joint. Deep dissection. Posterior view. File:Slide3bgbg.JPG, Elbow joint. Deep dissection. Posterior view.

References

External links

* * Photo of model at Waynesburg College
skeleton3/olecranonfossa
' * ()

Bones of the upper limb Humerus {{musculoskeletal-stub