A Case Report on Unclassified Anatomical Sciatic Nerve Variant in Acetabulum Fracture

Anatomical variations of the sciatic nerve are of significant clinical importance due to their implications in hip surgery, regional anesthesia, and the evaluation of sciatic neuropathies. The most widely accepted description of sciatic nerve-piriformis muscle relationships is the Beaton and Anson classification, which encompasses six recognized patterns. However, rare anatomical variants exist that do not conform to this classification and may predispose patients to nerve injury or diagnostic challenges.

We report a rare, unclassified anatomical variation of the sciatic nerve encountered intraoperatively during open reduction and internal fixation of a posterior wall acetabular fracture in a 32-year-old male following a road traffic accident. The sciatic nerve was observed to divide into its tibial and common peroneal components below the piriformis muscle; a pattern not described in existing classification systems.

Awareness of such atypical anatomy is essential for orthopedic surgeons to prevent iatrogenic nerve injury and highlights the need for further anatomical and radiological studies to expand current classification systems.