Anatomical Variations of the Sciatic Nerve Divisions in Relation to the Piriformis Muscle and Clinical Implications: A Human Cadaveric Study

Abstract

Background: The sciatic nerve is the largest nerve in the human body, formed by the union of five nerve roots (L4- S3) arising from the lumbosacral. The present study was conducted to assess variations of the sciatic nerve.
Materials & Methods: The present cross-sectional study was carried out on 80 lower extremities from 40 formalin fixed cadavers were examined during routine dissection. Anatomical variations were classified based on the Beaton and Anson classification system as Type-1: undivided nerve below undivided muscle b) Type-2: divisions of nerve between and below undivided muscle c) Type-3: divisions above and below undivided muscle d) Type-4: undivided nerve between heads e) Type-5: divisions between and above heads f) Type-6: undivided nerve above undivided muscle.
Results: Type 1 was found in 65 out of 80 (81.25%) lower limbs and is the most common variation in the adult cadaveric studies examined, followed by type 2 in 8, type 3 in 3, type 4 in 2, and type 5 in 2, respectively, as defined by the present study. The difference was significant (P< 0.05).
Conclusion: Clinical significance stems from the sciatic nerve's location, bifurcation, and distribution. Because the sciatic nerve is frequently used in routine medical procedures like anaesthesia, rehabilitation, orthopaedics, and neurology, its lengthy course renders it susceptible to damage.