Generally speaking, the meat of the back of the shoulders and neck is indeed relatively more abundant than the front side. The reasons for this are as follows: 1, the muscles of the back of the shoulder and neck are more plump. Because the human body is an upright walking animal. To remain upright, it is necessary to maintain a continuous contraction of the back muscles to maintain the four physiological curvature of the spine. If the muscles of the back were not so well developed, then it would be possible to maintain an upward arch of the entire spine, as in the case of a quadrupedal walking animal. In addition, only through the powerful contraction of these muscles, can make the trunk to maintain stability, by attaching the limbs, and make the limbs weak. 2, these parts of the muscle thick, the body’s internal organs play a very important role in the protection of the body. When the human body encounters danger, the first instinct will be curled up. At this time through the back of the thick muscles and subcutaneous tissue, to resist the direct violence suffered by the blow. 3, these parts of the muscle or subcutaneous fat is thick, but also to the human body to play a full role in keeping warm.