A 25-year-old man sustains a sacular fracture after a fall from height. CT shows the fracture line medial to the sacular foramina. He has loss of bladder control and perianal numbness. According to the Denis classification, this is a Zone III fracture. Which structure is MOST likely injured?

• A Cauda equina ✓
• B Sacral plexus
• C L5 nerve root
• D Pudendal nerve

Explanation

Zone III sacular fractures are medial to the sacral foramina and involve the central canal. They are associated with the highest rate of neurological injury, typically involving the cauda equina. This results in bowel/bladder dysfunction, perianal numbness (saddle anesthesia), and lower motor neuron deficits. Zone I and II fractures more commonly involve individual nerve roots (L5, S1).

Reference: Rockwood and Green's Fractures in Adults, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.