- The sciatic nerve is the largest nerve in the body and primarily responsible for transmitting pain signals in conditions of sciatic pain.
- It arises from the L4-S3 nerve roots and innervates the posterior thigh, leg, and foot. Compression or irritation of the sciatic nerve, often due to a herniated disc or spinal stenosis, leads to characteristic radiating pain along its distribution.
- Other nerves listed (femoral, tibial, obturator) do not encompass the typical pain pathway of sciatica.
- Thus, the sciatic nerve is the key structure in the pathophysiology of sciatic pain.

Reference: Davidson’s Principles and Practice of Medicine, 24th Edition, Chapter: Neurological Diseases, Page 855.