Monday, March 21, 2016

Coronoid, Trochlea, and learning the "elbow joint"

When studying the bones, we often study them one-at-a-time to learn the markings and attachment points. However, learning them together with adjacent bones can sometimes make the terminology easier to remember.

One great example of this is the humerus and ulna fitting together at the "elbow joint".

First, recall the general terms of "process" and "fossa". A process is a part of bone that "sticks out" and a fossa is a depression, or a part that "sinks in". Often when bones fit together, the process fits into the fossa. The mandibular process on the mandible fits into the mandibular fossa on the temporal bone.

The ulna and humerus are similar. The ulna has an olecranon process - the humerus has an olecranon fossa.  The ulna has a coronoid process - the humerus as a coronoid fossa. As the joint flexes and extends, the ulna rotates around the trochlea (which fits into the trochlear notch!)

If you Google "ulna and radius" you can find several images showing from various angles how the two bones fit together. Once you understand that, the locations of the olecranon fossa, the coronoid fossa, and the trochlear notch will become much easier to recall.

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