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Joseph Junewick, MD FACR
over 11 years ago
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Third Occipital Condyle

Case Detail

Anatomy: Brain-Spine
Joseph Junewick, MD FACR
Diagnostic Category: Normal variant
Created: over 10 years ago
Updated: over 9 years ago
Modality/Study Types: CT
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5 year old female with sinus congestion.

Case Images


Third Occipital Condyle


CT – Sagittal and coronal images reveal an ossicle in the anterior midline interposed between the clivus and dens.


The third occipital condyle (condylus tertius or median occipital condyle) was first described by J.F. Meckel in 1815, as a bony process in the anterior midline of the foramen magnum. It is always present in reptiles; in humans it is found in approximately 0.5% of the population and may exist as a discrete condyle or an isolated osseous element. It may serve as an articulation with the tip of the dens or with the anterior atlantic arch. The third occipital condyle is a vestige of proatlas (a derivative of the 4th occipital and 1st cervical sclerotome). The variations of the anatomic appearances of the third condyle can be explained by the different degrees of persistence. An isolated, articulated condylus tertius, located in the median-sagittal plane and the anterior margin of the foramen occipitale magnum represents the highest degree of persistence.


Prescher A, , Brors D, Adam G. Anatomic and Radiologic Appearance of Several Variants of the Craniocervical Junction. Skull Base Surgery (1996); 6:83-94.

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