At what level does the sciatic nerve typically divide into its terminal branches, the tibial and common fibular nerves?

Explanation

## Sciatic Nerve Division ### Anatomical Level of Division **Key Point:** The sciatic nerve divides into the tibial and common fibular (peroneal) nerves at the level of the **popliteal fossa**, typically just above the knee joint. This is the most consistent and clinically relevant landmark. ### Anatomical Course 1. **Origin**: Sacral plexus (L4, L5, S1, S2, S3) 2. **Exit**: Greater sciatic foramen 3. **Path**: Descends through the posterior thigh as a single trunk 4. **Division point**: Popliteal fossa (superior to knee) 5. **Terminal branches**: Tibial nerve (medial) and common fibular nerve (lateral) ### Clinical Significance **Clinical Pearl:** The division in the popliteal fossa is variable — in ~10% of individuals, the division occurs higher in the thigh or even within the pelvis. However, the standard anatomical position taught and tested is at the popliteal fossa level. **High-Yield:** Knowledge of this division point is critical for: - Popliteal fossa blocks (anesthesia) - Posterior knee surgery approach - Interpretation of nerve injury patterns ### Innervation by Terminal Branches | Nerve | Origin | Motor Supply | Sensory Supply | | --- | --- | --- | --- | | **Tibial** | Anterior division of sciatic | Calf muscles, foot intrinsics | Sole of foot, medial heel | | **Common Fibular** | Posterior division of sciatic | Anterior leg, fibularis muscles | Dorsum of foot, lateral leg | **Mnemonic:** **TiBial = Toe Benders** (plantarflexion), **Fibular = Foot Lifters** (dorsiflexion)