Surrounding the vaginal canal is the vaginal wall which is made up of fibrous muscle, skin and ligaments. There are two main vaginal walls namely, the front wall and the rear wall. The front wall is about seven centimeters in length while the rear wall is about nine centimeters in length.
The elasticity of the vaginal wall enables the vagina to stretch many times over to accommodate childbirth and sexual intercourse without tearing. During sexual foreplay when the clitoris is stimulated, the vaginal walls self lubricates. This natural lubrication facilitates the smooth, painless insertion of the penis into the vagina. The vaginal walls has a series of ridges also called the vaginal rugae which stretch and contract creating more surface area to fit the size of the penis. During childbirth the vaginal walls stretch and contract to accommodate the head of the emerging baby. The vagina is referred to as the birth canal during pregnancy and childbirth but actually the birth canal is really the area from the fully dilated cervix to the vagina and vulva.
The vagina involuntarily tightens because of a conditioned reflex action of the muscles in the vaginal wall. Intercourse, vaginal examination, tampon insertion and others trigger this response and this is called vaginismus.
The vaginal wall though elastic is also prone to sores and small ulcers due to trauma. Rape and forceful sexual intercourse, excessive rubbing and improper use of tampon can damage the vaginal wall. Sores and ulcers can also be caused by sexual transmitted diseases but can be cured by proper antibiotics and other medication.