## Sciatic Nerve Division **Key Point:** The sciatic nerve divides into the tibial nerve and common fibular (peroneal) nerve at the level of the popliteal fossa, typically in the lower third of the thigh or at the knee. ### Anatomical Course 1. **Origin**: Formed from L4–S3 nerve roots 2. **Exit from pelvis**: Greater sciatic foramen, below piriformis muscle 3. **Course in thigh**: Descends in the posterior compartment between hamstrings and adductors 4. **Division point**: Popliteal fossa (at or just above the knee) - Tibial nerve (medial division) - Common fibular nerve (lateral division) ### Variations The division may occur: - Higher in the thigh (in ~12% of cases) - Lower in the popliteal fossa (in ~10% of cases) - Rarely, the two components may remain separate throughout the thigh **Clinical Pearl:** High division of the sciatic nerve is clinically significant during posterior knee approaches and popliteal nerve blocks — the anesthetist must account for potential separate tibial and peroneal nerves. **High-Yield:** The popliteal fossa is the standard anatomical landmark for sciatic nerve division in all standard anatomy texts and surgical approaches. 
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