A man’s urethra has a diameter of about 5-7 millimeters and a length of about 16-22 centimeters, and is divided into three parts, namely, the prostate, the membranes, and the corpus cavernosum. 1. The prostatic part: is the part of the male urethra that passes through the prostate gland and is about 3~3.2 centimeters long. 2. Membranous part: It is the part of the urethra that passes through the genital diaphragm and is about 1.5~1.6 cm long, surrounded by muscle tissues, which can control urination and is easily injured when the pelvis is damaged. Clinically, this part and the prostate are collectively called the posterior urethra. 3. Spongy part: for the urethra through the spongy part of the length of about 12 to 17 centimeters, called the anterior urethra, can be touched by hand, can also be observed. The male urethra has its own special anatomical structure that is three narrow, three dilated and two curved, so in the clinical cystoscopy or catheterization should be carefully operated to avoid medical injury. Because the male urethra is longer and has a special anatomical structure, it is prone to urinary tract infections such as urethritis, therefore, it is usually necessary to keep the urethra open. In addition, because the male urethra passes through the pelvic floor area, so should avoid sedentary, hold urine.