Sciatic nerve behind (superficial to) the adductor magnus muscle, and is itself in front of (deep to) one head of the biceps femoris muscle. At the popliteal fossa, the nerve divides into its two branches: The sciatic nerve is the largest nerve in the human body. The sciatic nerve supplies sensation to the skin of the foot, as well as the entire lower leg (except for its inner side). Sensation to skin to the sole of the foot is provided by the tibial nerve, and the lower leg and upper surface of the foot via the common fibular nerve. The sciatic nerve
Human body and about 23 litres of fluid inside cells. The content, acidity and composition of the water inside and outside cells is carefully maintained. The main electrolytes in body water outside cells are sodium and chloride, whereas within cells it is potassium and other phosphates. The body contains trillions of cells, the fundamental unit of life. At maturity, there are roughly 30–37 trillion cells in the body, an estimate arrived at by totalling the cell numbers of all the organs of the body and cell types. The body is also host to about the same number of non-human cells as well