## Sciatic Nerve: Anatomy and Course ### Formation and Exit from Pelvis **Key Point:** The sciatic nerve is formed by nerve roots L4, L5, S1, S2, and S3 within the pelvis. It exits the pelvis through the **greater sciatic foramen** (not the obturator foramen), passing below the piriformis muscle. **High-Yield:** The obturator foramen is traversed by the obturator nerve and obturator vessels — a common source of confusion in anatomy exams. ### Course in the Thigh The sciatic nerve descends in the **posterior thigh** (not anterior), lying on the adductor magnus muscle. It is the longest and thickest nerve in the body. ### Terminal Branches | Branch | Characteristics | Course | |--------|-----------------|--------| | **Tibial nerve** | Medial and larger terminal branch | Continues into the leg, supplies posterior compartment | | **Common fibular nerve** | Lateral and smaller terminal branch | Winds around fibular neck (superficial and vulnerable) | **Clinical Pearl:** The common fibular nerve's superficial course around the fibular neck makes it highly susceptible to compression injury from tight casts, prolonged squatting, or external pressure — a classic exam scenario. ### Why Option 4 is Incorrect The sciatic nerve exits via the **greater sciatic foramen**, not the obturator foramen. This is a critical anatomical landmark tested frequently in NEET PG. **Mnemonic:** **GOFP** — Greater foramen = sciatic nerve; Obturator foramen = obturator nerve; Foramen ovale/spinosum = cranial nerve passages; Pyriformis = landmark for sciatic exit.
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