Anatomy of the femur and tibia

The first of the leg bones is the thigh, and it is the largest bone in the body, since it carries what is above it and moves what is below it. Its upper end is given the appearance of a dome so that it can be located in the “thigh box”. The hip is curved outward and forward, concave and directed inward and backward. If it were created in the form of a straight line, parallel to the “box,” then a kind of gait disorder would certainly arise, which occurs in those who are so built. In such a person, the large muscles, nerves and blood vessels of the thigh are poorly protected; Nothing comes out right from all this and his manner of sitting is not good. Further, again, if the hip were not directed inward, a different kind of gait disorder would result. In order to stand, there would be no middle line towards which one leans and deviates, and one would not be able to maintain balance. At the lower end of the thigh there are two protrusions to form the knee joint. Let's talk first about the lower leg, then about the knee joint.

The lower leg, like the forearm, consists of two bones. One of them is larger and longer and is located on the inside; it is called the "big cane". The other bone is smaller and shorter; it reaches the thigh, but is shorter than it, and from below it reaches the same place where the big bone reaches. It is called the "small cane". The lower leg also has an inward curve so that a person can stand well and maintain balance. The “big cane”, that is, the lower leg in the true sense of the word, is created shorter than the thigh and here’s why. The fact is that this bone j combines two properties; one of them requires greater size, and this property is stability and the ability to carry what is above it. Another property requires greater shortness, and this is ease of movement. Since the second requirement is closer to the goal sought in the lower leg, this bone is created shorter, and the first requirement is closer to the goal required from the thigh, which is why the thigh is created larger. The shin is given an average size, because if its size were increased, then there would be difficulty in movement, which happens in people with elephantiasis and with dilated veins. And if it were shorter, there would be weakness, difficulty in movement and the inability to carry what is located higher, as happens in people with thin legs. Because of all this, the “big cane” is supported and strengthened by the “little cane.” The “small cane” also has other benefits. For example, it covers the nerves and vessels located between the “large and small canes”, and participates with the “large cane” in the formation of the joint of the foot, so that the joint that performs extension and flexion is stronger and stronger.