Paramastoid Process

Description

Coronal-reformatted CT showing bilateral paracondylar processes (P) arising from the paracondylar area of the occiput and extending inferiorly to articulate (white arrows) with the superior aspect of transverse process (T) of atlas.

Name

• Paracondylar process or tubercle
• Paraoccipital
• Paramastoid
• Parajugular
• Estiloid process
• Massa paracondylica
• Epitransverse process

General

• Rate anatomical variant of the occipital bone
• The bone exostosis extends caudally from the paracondylar region
• Typically it will articulate with the superior surface of the transverse process of atlas
• Part of the spectrum of occipital vertebrae

Epidemiology

• Rare
• Reported prevalence of 0.5% to 2%
• Unilateral more common than bilateral

Clinical Presentation

• Typically incidental/ asymptomatic
• Can become symptomatic if it fuses with Atlas, resulting in reduced atlanto occipital joint range of motion
• May cause bone torticollis

Radiographic Features

• Best viewed on coronal CT
• Broad, bony protuberance arising from the inferior aspect of the jugular process of the occiput

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Clinical Significance

Pathology

• Bony Torticollis

Surgical Considerations

• Can affect lateral approach to neck dissection or surgery of the dural venous sinus

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See Also

• Accessory Bones Main
• HEENT Anatomy Main

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