A 45-year-old man has low back pain with radiation along the front of the right thigh, weakness of knee extension, and a diminished right knee jerk. The femoral stretch test reproduces his anterior thigh pain. Which disc level is the most likely site of herniation?
- A L2-L3 ✓
- B L4-L5
- C L5-S1
- D T12-L1
Correct answer: A. L2-L3
Explanation
Upper lumbar disc herniations are uncommon but produce an L3 or L4 radiculopathy: anterior thigh pain, quadriceps weakness, depressed knee jerk, and a positive femoral stretch test. An L2-L3 herniation typically compresses the L3 root. An L4-L5 herniation compresses L5, giving foot drop with a normal knee jerk and negative femoral stretch, while L5-S1 compresses S1, producing calf pain, plantarflexion weakness, and an absent ankle jerk.
Reference: Apley's System of Orthopaedics and Fractures, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.