The skin is the largest sensory organ of the human body, arising in the human embryo from the same cell layers as the nervous system, the ectoderm. The number of sensory fibers from the skin entering the spinal cord is well over half a million. In a sense, the nervous system is part of the skin, or the skin is an external nervous system, conveying knowledge of the environment to the organism. In the evolution of the senses, the tactile system was the first system to come into being in all species. The sense most closely associated with the skin, the sense of touch, is the earliest to develop in the human embryo.
Touch means contact, a relationship with what lies outside our own periphery.
For humans touch is of vital importance, giving reassurance, warmth, pleasure and vitality. It tells us that we are not alone. The cuddling and stroking we receive in infancy helps us build a healthy image of ourselves and nurtures the feeling that we are accepted and loved. Psychologists have demonstrated that our perception of how much we are touched relates to how we value ourselves, our self-esteem. With the increased physiological and emotional stress of pregnancy, an occasional massage can be of significant benefit.