The fore- and hind limbs were evolved basically forbearing the weight of the body and for locomotion asis seen in quadrupeds, e.g. cows or dogs. The two pairsof limbs are, therefore, built on the same basic principle.Each limb is made up of a basal segment or girdle,and a free part divided into proximal, middle and distalsegments. The girdle attaches the limb to the axialskeleton. The distal segment carries five digits.Table 1.1 shows homologous parts of upper and lowerlimbs.However, with the evolution of the erect posture inman, the function of weight-bearing was taken over bythe lower limbs. Thus the upper limbs, especially thehands, became free and gradually evolved into organshaving great manipulative skills.This has become possible because of a wide range ofmobility at the shoulder. The whole upper limb worksas a jointed lever. The human hand is a grasping tool.It is exquisitely adaptable to perform various complexfunctions under the control of a large area of the brain.The unique position of man as a master mechanic ofthe animal world is because of the skilled movementsof his hands

The fore- and hind limbs in quadrupeds, such as cows or dogs, have evolved to bear the weight of the body and for locomotion. Both pairs of limbs follow the same basic principle. Each limb consists of a basal segment or girdle, and a free part divided into proximal, middle, and distal segments. The girdle attaches the limb to the axial skeleton, while the distal segment carries five digits. Table 1.1 illustrates the homologous parts of the upper and lower limbs.

However, in humans, with the evolution of an erect posture, the lower limbs have taken over the function of weight-bearing. As a result, the upper limbs, especially the hands, have become free and gradually evolved into organs with exceptional manipulative skills. This transformation has been made possible due to the wide range of mobility at the shoulder. The entire upper limb functions as a jointed lever, and the human hand serves as a grasping tool. It is remarkably adaptable and capable of performing various complex functions under the control of a large area of the brain.

The unique position of humans as master mechanics in the animal world is attributed to the skilled movements of their hands.