📌 Not an osteophyte. Not an osteochondroma. Not a fracture.

https://youtube.com/shorts/k0sEdDezBPE

 

Accessory articulation of the cervical transverse process is a rare congenital variant caused by elongation of the anterior tubercle (costal element), forming a pseudoarthrosis with the adjacent cervical vertebra.
Most commonly reported at C5–C6; C6–C7 is exceptionally rare.

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Why this matters

On AP cervical X-ray and axial CT, this anomaly can closely mimic:

• Acute transverse process fracture
• Fracture fragment
• Osteophyte or osteochondroma-like bony lesion

This pitfall is most dangerous in acute trauma settings, where a linear lucency at the anterior tubercle is easily misread as a fracture line.

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Major imaging pitfall

• Axial CT alone can be misleading
• The pseudoarthrosis gap may appear as an oblique or linear lucency
• Multiplanar reformats (coronal/sagittal ± oblique) are essential

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Key CT differentiation points

Accessory articulation

• Originates from the transverse process, not the vertebral body
• Smooth, corticated bony extensions
• Uniform, joint-like gap between adjacent tubercles
• Secondary osseous hypertrophy indicating chronic stress remodeling
• No displacement, no soft tissue swelling

 

Acute fracture

• Sharp, irregular fracture line
• Cortical disruption ± fragment separation
• Morphology consistent with trauma pattern
• Often associated soft tissue injury
• Bone marrow edema if MRI is performed

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Clinical concept

When symptomatic, this congenital pseudoarthrosis may function as a mechanical pain generator, conceptually similar to a cervical analogue of Bertolotti’s syndrome.

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Take-home point

If an “anterior tubercle fracture” looks too smooth, symmetric, and corticated,
pause—and confirm whether this is a congenital accessory articulation.

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#CervicalSpine #Radiology #FractureMimic #CTPitfall #MSKRadiology
#SpineImaging #XrayPitfall #CongenitalVariant #Neuroradiology #CervicalCT, #Vibecase

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