FOOT. The lower end of the leg that rests on the ground. In the human foot the bony structure is made up of three divisions, the tarsus, metatarsus and phalanges. Seven bones form the tarsus; the os calcis or heel bone, the largest and strongest of all, carries the principal part of the body's weight. On its posterior surface the large muscles of the calf find their attachment through the tendon Achilles. Half in front of the os calcis and superimposed upon it is the next largest bone, the astragalus. This bone bears directly the weight of the body through the large leg-bone, the tibia, resting on the upper surface. On the outer side in front of these two bones is the cuboid, and on the inner side the scaphoid or navicular bone. In front of the scaphoid there are the three small cuneiform bones, internal, middle and external. These three bones with the cuboid form articulations with the next row or division. The metatarsus is formed of five so-called long bones; that is, each bone has a shaft and articulating extremities. To each of these is joined one of the next division or phalanges. These are also long bones, the great toe made up of two bones, and the others of three each. Strong ligaments bind these bones to one another in such a way as to form and maintain an arch extending forward and back ward, and somewhat from side to side, the points of contact with the ground being only with the os calcis behind and the metatarsus and phalanges in front — the so-called ball of the foot. By this arrangement shock is trans mitted through an arch or spring, pads at these two points also further eliminating jars. The sole of the foot is also covered with small muscles, which move the toes, and tendons that flex the toes and extend the foot on the ankle. Across the dorsum or instep pass the flattened tendons that flex the foot and extend the toes.
The chief artery to the sole comes down on the inner side of the heel, passing across to the outer side, then arching across to the inner side again, giving off branches to the toes. On the dorsum the main artery comes to the sur face at the instep and forms an arch of supply to the toes. The nerves on both surfaces closely follow the arteries.
Among the lower animals, monkeys have feet that approach nearest to those of the human. The separation of the great toe, in a way corresponding to the thumb, and the ab sence of the arch are the points of difference. In many of the animals, as in the cat tribe, there is a greater or less tendency toward a rudimentary inner toe, and an increase of the function of the ball of the foot, with a lessen ing of the importance of the heel. In the cattle and equines the toes are fewer, and the nails or claws become converted into hoofs. The horse walks on the end of his single digit.
In measure of length, the foot is derived from the assumed length of the human foot, containing 12 linear inches. A square foot is a square whose side is one foot, and is there fore equal to 144 square inches. A cubic foot is a cube whose side is one foot, and the cube contains 1,728 cubic inches. The foot is a com mon measure in various countries, but its dimen sions vary somewhat. In poetry, a measure consisting of a variety of syllables, two, three or four, in combinations of long and short, or accented and unaccented syllables. The num ber of possible varieties of feet is reckoned at 28. (See Rinrrn ) In mechanics and popular usage, the lower part of a thing, especially the lower end of a leg, as of a table, desk, etc.