Metatarsal bones Metatarsal bones The metatarsal bones, or metatarsus are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the medial side (the side of the great toe): the first, second, third, fourth, and fifth metatarsal (often depicted with Roman numerals). The metatarsals are analogous to the metacarpal bones of the hand. The lengths of the metatarsal bones in humans are, in descending order: second, third, fourth, fifth and first. The five metatarsals are dorsally convex long
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