The sciatic nerve is the biggest and longest nerve of the human body.  At it’s thickest point, in a human, it can be as thick as three quarters of an inch in diameter.   It is as long as the distance between the lower spine and the back of the knee of a person.  We have two sciatic nerves in our body.  They start on either side of the base of the spine.  Each trails down separately behind each of our buttocks,  and continues down our thighs, to behind our knees, and they branch out into other important nerves which culminate at our feet.

Thanks to the sciatic nerve we feel sensations and control the movement of most of the lower half of our bodies.  The flexing of our hips and our knees is coordinated by the sciatic nerve, and even the motion of our feet is dictated by it, and its extensions.  It is the sciatic nerves that communicates what happens to the lower part of our bodies, to our spinal cord, and, thus, to the brain.  This is because the sciatic nerve is derived from spinal nerves at he base of the spine.

Each sciatic nerve is subdivided into two branches: the articular branch and the muscular branch.  The articular branch is the nerve function which controls the hip joint.  The muscular branch commands most of the major muscles of the legs and, after branching off below the knee, it also influences the muscles of the feet.