CAMRT Radiography Practice Exam

Which part of the occipital bone helps to form the atlantooccipital joint?

1. Occipital protuberance

2. Occipital condyles

3. Foramen magnum

4. External occipital crest

The correct answer is: Occipital condyles

The atlantooccipital joint is the articulation between the occipital bone of the skull and the first cervical vertebra, known as the atlas. The occipital condyles are specifically designed for this joint and are located on the inferior aspect of the occipital bone. These two rounded projections articulate with the superior facets of the atlas, allowing for the nodding motion of the head, such as when saying "yes." The other parts listed do not play a direct role in forming this crucial joint. The occipital protuberance is a prominent bump on the back of the skull, primarily serving as an attachment point for muscles and ligaments. The foramen magnum is a large opening at the base of the skull through which the spinal cord passes, critical for nervous system connections, but it does not participate in the joint structure. The external occipital crest is a ridge running vertically down the back of the skull, but it again lacks direct involvement in joint formation. Thus, the occipital condyles are the key components that enable the articulation necessary for the atlantooccipital joint.