Arms and legs are the main base of our body. we cannot work without it.
The framework of each upper and lower limbs is made up of three long and small bones.
The upper limbs, called the forelimbs or arms, are joined to the backbone with the help of shoulder girdle (shoulder blade and collarbone make up the shoulder girdle). The arm has one long bone called the humerus. The lower arm has two long bones. The wrist and hands have several small bones.
The bones of the lower limbs, called the hind limbs or legs are attached to the hip bone(hip bone is made up of three bones joined together). The upper half or the thigh bone of the leg, also called the femur, is the longest bone in the body and bears the weight of the whole body. The lower half of the leg has the shin bone and the calf bone. There are several small bones which make up the foot.
NOTE:
The long bones of the arms and legs are hollow tube-like structures. such structures are very strong which can hold weight and tolerate pressure.
That is why we are not only able to carry our weight but can also lift more weight and walk.
