Question

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

• A. L4
• B. L5
• C. L3
• D. S1

Hint:

The L5 nerve root is commonly involved in cases of sciatic nerve pain, often triggered by activities like lifting or bending.

Answer 1

The Correct Option is B

Pain in the back of the leg and the thigh after lifting a heavy weight can indicate a problem with a specific spinal nerve root. The sciatic nerve, which originates from the lumbar and sacral spine segments, primarily innervates the back of the leg and thigh.

The anatomy of the sciatic nerve is critical in diagnosing the specific segment involved when there's referred pain. The segments L4, L5, and S1 are particularly important in terms of their contributions to the sciatic nerve:

• L4: Involves the anterior and medial thigh; not primarily responsible for posterolateral leg pain.
• L5: Innervates the lateral side of the leg and dorsum of the foot; linked to pain radiating down the posterolateral aspect of the leg and thigh.
• L3: Innervates the anterior thigh; unlikely to cause posterior leg pain.
• S1: Associated with posterior leg and foot but typically affects the heel area more than the back of the thigh.

Considering the involvement of pain in the back of the leg and thigh, it suggests the involvement of the L5 segment, which is responsible for these areas due to its contribution to the sciatic nerve, especially affecting the posterolateral aspect.

Therefore, the correct spinal segment involved in this pain distribution pattern is L5.