Boys have cracks in the foreskin, mostly seen in patients with a long foreskin or phimosis, but also may be caused by trauma or inflammation. 1. long foreskin or phimosis: if the patient’s foreskin is long or phimosis, strenuous masturbation, sex or forced upward turning of the foreskin may appear foreskin injury, resulting in a crack in the foreskin. 2. Inflammatory infections: patients with glans phimosis who have repeated infections can cause the tension of the foreskin to increase and the elasticity of the foreskin to decrease, and it is easy for the foreskin to split under the action of external forces. 3. Trauma: If the foreskin has scratches, cuts, etc., corresponding cracks can also appear. Cracks in the foreskin may also be caused by other factors, it is recommended that patients go to the regular hospital in time for treatment, and strive for early recovery.