The belly of the little finger refers to the part of the palm surface of the hand where the distal joint of the little finger is opposite to the nail. The belly of the finger has a thick fat pad under the skin, the skin cuticle is thicker, the subcutaneous fiber spacing can connect the skin with the finger bone, tendon sheath and other deep tissues, the distal joints transverse lines of the subcutaneous fiber spacing so that the belly of the finger to become a closed gap, which prevents the skin from slipping, the hand and the object in direct contact with the hand is conducive to the hand to grasp the object to increase the stability. The skin of the finger belly is rich in sweat glands, no hair and sebaceous glands, and there are fingerprints on it, which can increase the friction between the hand and the object when contacting, which is favorable for people to grasp the object, and at the same time, fingerprints are affected by the genetic factors, which results in different fingerprints for each person.