The urethra is the canal that leads from the urinary bladder to allow for urine to be expelled into the environment. In men, the urethra also carries semen, traverses the prostate gland which lies below the bladder and runs through the penis. In women, the urethra is much shorter and terminates just anterior to the vagina.
The urethra is a muscular tube that starts an the bottom of the bladder known as the internal urethral orifice. It is about 20 centimeters long (between 18 to 22 centimeters) in men, whereas in women, the urethra is only 4 centimeters long. The external urethral orifice is where the urethra terminates and in males this is located at the tip of the glans penis. The female urethra terminates in the vestibule between the labia minora, lying between the clitoris and vaginal orifice.