Third condyle

Dr Henry Knipe and Dr Craig Hacking et al.

The third condyle (also known as condylus tertius or median occipital condyle) is a rare anatomic variant of the occipital condyles. It is a small separate ossicle at the anteromedial margin of the occipital condyle formed by the failure of the embryonic proatlas (4th occipital sclerotome) to unite with the condyle proper.

It may form a true arthrosis or pseudoarthorosis with the adjacent odontoid process of the axis or anterior arch of the atlas and has an association with an os odontoideum.

Practical points

This anatomic variant may mimic an occipital condyle fracture.

Head and neck anatomy
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Article information

rID: 56027
Section: Anatomy
Synonyms or Alternate Spellings:
  • Condylus tertius
  • Median occipital condyle

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