Which part of the human body is most sensitive to touch?

Sensory nerve and motor nerve are distributed in normal skin, and their nerve endings and special receptors are widely distributed in epidermis, dermis and subcutaneous tissue to sense various stimuli inside and outside the body, cause corresponding nerve reflex and maintain the health of the body. Therefore, the skin has six basic feelings, namely, touch, pain, cold, warmth, pressure and itching.

Touch is one of the basic feelings of the skin. Contacts are scattered on the skin surface, with different sizes, some of which can reach 0.5 mm in diameter. Its distribution is also irregular, generally the abdomen is the most, followed by the head, calf and back are the least. Therefore, the fingertips are the most sensitive to touch, and the calves and back are the most dull. Touching your finger belly with thread will have obvious touch, while touching your calf will be completely unconscious. This is why you can know whether you need a card by touching it with your fingers without looking at the cards when playing mahjong, but touching your back skin with two blunt needles 0.5cm apart is mistaken for an object.