The sacral plexus lies on the posterior wall of the pelvis over piriformis. It is formed by the anterior primary rami of S1 to S4 together with which additional contribution?

• A Lumbosacral trunk formed by L4 and L5 ✓
• B Anterior ramus of L3 only
• C Posterior ramus of S5 and the coccygeal nerve
• D Genitofemoral nerve from L1 and L2

Explanation

Part of the L4 root joins L5 to form the lumbosacral trunk, which descends over the pelvic brim into the pelvis and unites with the anterior rami of S1 to S4 on piriformis to form the sacral plexus. The genitofemoral nerve remains on the anterior abdominal wall, and the coccygeal contributions form the small coccygeal plexus instead, ruling out C and D.

Reference: Snell's Clinical Anatomy by Regions, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.