Alar ligament calcification

Case contributed by Dr Antonio Rodrigues de Aguiar Neto


This patient presented with complaints of neck pain and pulsatile left hemicranial headaches — no history of trauma.

Patient Data

Age: 45 years
Gender: Female

There is a corticated ovoid calcification, measuring about 4.2 x 5.1 x 6.5 mm, located between the odontoid tip and the right occipital condyle, along the course of the right alar ligament. There were no other calcifications in the other ligaments of the craniovertebral junction.

There was no evidence of fractures in the odontoid process, the occipital condyles, or the neural arch of the atlas. The spinal canal appeared normal, and there was no dislocation C1-C2.

Case Discussion

The alar ligaments arise from both sides of the tip of the odontoid process and run obliquely cephalad to insert on the medial surface of the occipital condyles 1,2,3. Calcification of the alar ligament is rare 1-4. This condition should be differentiated from fractures of craniovertebral junction, as well as from crowned dens syndrome 1,4.

The present case illustrates the typical features of focal calcification in the right alar ligament, associated with neck pain.

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