Question

Pain in back of leg and thigh after lifting heavy weight. Which segment involved?

• A. L4
• B. L5
• C. L3
• D. S1

Hint:

Sciatica after lifting = posterolateral disc prolapse; the most commonly trapped root at L4–L5 is the traversing root.

Answer 1

The Correct Option is B

Step 1: Identify the clinical picture. Pain that begins after lifting a heavy weight and radiates down the back of the thigh and leg is classic sciatica caused by a lumbar intervertebral disc prolapse compressing a lumbosacral nerve root. The most common levels for disc herniation are L4-L5 and L5-S1.

Step 2: Map the dermatome to the root. The L5 nerve root supplies the lateral aspect of the leg, the dorsum of the foot and the great toe, and pain referred along the posterior thigh and posterolateral leg is typical of L5 radiculopathy. The L5 root is the most frequently involved root in lifting-related disc prolapse (an L4-L5 disc herniation classically compresses the traversing L5 root).

Step 3: Why L5 (option B) is correct. Posterior thigh + leg pain after lifting fits an L4-L5 prolapse compressing the L5 root, the single most common root affected by mechanical lifting injuries.

Step 4: Why the other options are wrong. L4 (option A) radiculopathy gives anteromedial leg pain with a depressed knee jerk and weak quadriceps, not posterior-thigh pain. L3 (option C) involvement causes anterior thigh pain and is uncommon in lifting injuries. S1 (option D) involvement causes pain down the posterior calf to the sole/lateral foot with a depressed ankle jerk and weak plantarflexion; while plausible, the classic answer for this presentation is L5.

Final answer: B (L5).