Sciatic nerve

A crucial nerve that extends from the lower back down each leg, providing movement and sensation.

The sciatic nerve is the longest and widest single nerve in the human body. It originates from the lumbar and sacral plexus in the lower back, specifically from spinal nerves L4 to S3. This nerve travels down the back of each leg, branching into smaller nerves that innervate various muscles and skin areas, allowing both voluntary movements and the perception of touch and pain.

Terminologia Anatomica

nervus ischiadicus

System

Nervous system

Function

The primary function of the sciatic nerve is to relay signals between the brain and the lower body. It plays a critical role in facilitating movement, as it innervates major muscle groups responsible for actions such as walking, running, and jumping. More specifically, it controls the muscles in the back of the thigh (hamstrings), the lower leg, and the foot. Moreover, the sciatic nerve is also responsible for transmitting sensory information from the skin of the outer leg and the foot back to the brain, enabling sensations such as touch, temperature, and pain. This dual role highlights the sciatic nerve's importance in maintaining mobility and protecting the body from injury through sensory feedback.

Location

The sciatic nerve begins in the lower back, where it exits the spinal column through openings in the vertebrae. After its origin, it travels through the pelvis and exits the pelvis posteriorly, passing beneath the piriformis muscle in the buttock. From there, it descends down the back of the thigh, where it typically divides into two main branches: the tibial nerve and the common peroneal nerve. This descent follows the posterior aspect of the leg, continuing into the calf and foot, making it easily accessible for understanding its function in both locomotion and sensation throughout the lower extremities.

Did You Know?

Sciatica, often resulting from compression or irritation of the sciatic nerve, can cause sharp pain radiating down the leg.
Despite common belief, not everyone with sciatic nerve pain will feel discomfort in the back; some may experience symptoms primarily in the leg.
The sciatic nerve can be affected by various conditions, including herniated discs, spinal stenosis, and muscle spasms.
Stretching and strengthening exercises targeted at the lower back and legs can help manage sciatic nerve pain.