The structure of the foot as a sign of the evolutionary perfection of the human body.

Evolutionary alignment made it uniqueSome parts of the human skeleton, which have no analogues among similar parts of the skeleton of other representatives of the animal world. First, the shape of the spine has changed, which allowed a person to be constantly in an upright position relative to the surface of his movement. And secondly, nature, given the constant load on the legs, changed the skeleton of the foot, so that, in turn, did not experience fatigue during walking or standing. Every day, performing any motor act involving the lower extremities, a person, in one way or another, exerts pressure of his own weight on this seemingly fragile and small anatomical region. The structure of the foot is very difficult in its essence, because in this structural unit contains a large number of bones, ligaments, joints and very thin, as well as various in their functional features of the muscles. The core here, as well as in any other part of the body, is the bones that form the characteristic appearance of the foot. As in the upper limbs, and in the foot, three important departments are distinguished.

1. Tarsus.This is the part that connects the large tubular bones of the lower limb with the small ones. According to its histological structure, the tarsal bones can be classified as spongy, having very short dimensions. In total, there are seven small ossicles in the tarsal, the largest of which are the talus and heel bone. The rest, namely three wedge-shaped, cube-shaped and navicular bones in their dimensions considerably inferior to the first two. The structure of the foot especially in that it has a large number of joint articulations on a relatively small surface. The talus bone together with the bones of the lower leg forms an ankle joint. The remaining bones of the human foot are also connected to each other with the help of other joints.
2. The plus.It is the middle part between the tarsal bones and phalanges of the toes. The bones of the metatarsal are somewhat distal from the three cuneate and cuboid bones. In the metatarsal bones, there are three landmarks: the head that connects them to the phalanges, the body and the base that connects these anatomical structures with the tarsal bones of the small joints.
3. Phalanges of fingers.They are, as a rule, three, not counting the first finger, in which there are only two phalanges. This is the only part in the foot that can bend and unbend, not considering the ankle joint, which is half of the bones of the shin.

The structure of the foot has one more specificfeature, and all thanks to the vertical position of the whole body. The fact is that the longitudinal axis of the foot is located almost at right angles to the vertical axis of the proximal part of the lower limb, however, the bones of this area are not in the same plane, because part of them forms a longitudinal, and the other part a transverse arch. The concave half of the foot is turned towards the sole, and the convex half is to the rear surface, respectively. This structure of the foot provides springiness, smoothness and elasticity of the gait. At rest in a healthy person, only the heel bone (its hillock) and the head of the bones of the metatarsus touch the floor tightly. All the rest that belongs to the earth is soft foot tissues. At this moment, i.e. at the moment of rest, the supporting arch, which is represented by the outer surface of the foot, also touches the ground, and its opposite inner edge is slightly raised from the floor and plays the role of a spring (spring vault). During walking, the spring vault is flattened, then again returns to its original position, thereby softening the step and minimizing the weight load on the foot itself.