Paracentral disc protrusion

Case contributed by Frank Gaillard


Acute back pain and right posterior calf pain after heavy lifting. On examination, there was an absent right ankle jerk, but no other neurological signs.

Patient Data

Age: 25 years
Gender: Male

Note: This case has been tagged as "legacy" as it no longer meets image preparation and/or other case publication guidelines.

L5/S1 disc level


An asymmetrical soft tissue density arising from the L5/S1 disc and protruding into the spinal canal, reflecting a paracentral disc protrusion. It is encroaching upon the right lateral recess compressing the right S1 traversing nerve root.

Case Discussion

This is a large right paracentral focal disc protrusion. The L5 nerve roots were not compressed, leaving in the intervertebral foramen above the disc (not shown). The right S1 nerve roots are almost certainly compressed, accounting for the patient’s symptoms and signs.


Fardon DF, Milette PC. Nomenclature and Classification of Lumbar Disc Pathology. Recommendations of the Combined Task Forces of the North American Spine Society, American Society of Spine Radiology, and American Society of Neuroradiology 2003

 Image contributed by: Dr Laughlin Dawes

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