The last place a child passes during birth is the birth canal. This area on the female serves several purposes and is referred to by a different name outside of birth.
The birth canal is the passage between the vaginal opening and cervix. It is also known as the vagina.
The main function of the birth canal is to allow a baby to pass from inside the mother's uterus to the outside world. The birth canal also allows fluids such as blood and cervical mucus to pass from the body.
The birth canal consists of three types of tissue: mucosa, muscle and fibrous tissue. The mucosa is the outer smooth layer which provides lubricating secretions to the canal. The muscles and fibrous tissue are underlying and control the shape and size of the birth canal.
The birth canal is located at the lower end of the vulva. It is directly below the urethra and above the anus.
The average human birth canal is between 3 and 4 inches deep. When aroused, the birth canal can stretch up to 7 inches deep.