The glans penis is covered with foreskin on the outside. The skin of the glans is keratinized above the squamous and resistant to friction. The foreskin is divided into inner and outer plates, and the skin at the opening of the foreskin consists of the inner and outer plates migrating and is soft. Since there is no subcutaneous fat under the skin of the penis and it is rich in collagen, it is more elastic and has better stretchability, thus adapting to the function of the penis. After birth, the foreskin and glans are in a state of adhesion and cannot be turned up to expose the glans. 2 years old, the adhesion between the foreskin and glans is gradually separated by itself and the foreskin can be turned up to expose the urethral opening and glans. After entering puberty, with the development of the penis, the erection of the penis increases at night, and the foreskin gradually recedes at the coronal groove, leaving the glans exposed. During the development of the penis, factors such as inadequate separation of adhesions lead to different shapes of different penile foreskins. There are the following three kinds: 1, prepuce Commonly found in children and some adults. The foreskin covers the glans, the foreskin opening is narrow, and the foreskin cannot be completely turned up to expose the urethral opening or glans. It can appear that the foreskin cavity fills up first when urinating and then the urinary line appears, and in serious cases, it can lead to inflammatory urethral stenosis, which affects urination; foreskin scale gathers in the foreskin cavity and cannot be excluded, and a round or oval lump under the foreskin appears. Partial adhesion of the foreskin to the glans. Easy to lead to acute inflammation of the foreskin glans, the appearance of the foreskin mouth redness, swelling, pus flow phenomenon. 2.Circumcision is common in adults, and most Chinese people belong to this type. The foreskin completely or partially covers the head of the penis, but can be turned up to expose the glans and urethral opening. Most of the foreskin mouth is loose and spacious, and the foreskin can be easily turned up. A small number of foreskin mouth is narrow and can be turned up, but after turning up, the narrow foreskin mouth is bound at the coronal groove, which can easily lead to foreskin entrapment, resulting in foreskin swelling and obstruction of blood circulation to the glans, which can lead to ischemic necrosis of the glans in serious cases; in addition, it can lead to local discomfort during sexual life. In short, long foreskin keeps the foreskin cavity in a humid state and foreskin scale cannot be removed in time, which can invite the reproduction of bacteria, produce odor and glansitis, and is a high risk factor for penile cancer. Therefore, the foreskin should be turned up every day to freshen the foreskin cavity and keep the local cleanliness and hygiene, and the foreskin should be turned up when urinating and reset in time. 3.Normal shape The glans is always exposed when the penis is weak and the foreskin is located behind the coronal sulcus. It is seen in adults. What is the need for circumcision? Circumcision can be performed after puberty if it does not affect urination and no inflammation occurs. If the foreskin is too long: if the foreskin mouth is loose, can form good hygiene habits, keep the foreskin cavity local clean and hygienic, can not circumcision. If the foreskin mouth is narrow, although it can be turned up to expose the glans and urethral opening, it is still recommended to perform circumcision.