Vaginal vault prolapse is when the top of the vagina drops near or through the opening of the vagina. It is usually caused by weakness of the muscles and tissues in the pelvis or vagina. It can occur following surgical removal of the uterus (hysterectomy), especially if you've had a previous prolapse. When the top of the vagina loses the support of the uterus, it can drop into the vaginal canal.

The amount of the drop in a vaginal vault prolapse can vary from a slight drop into the vaginal canal to a complete drop, where the top of the vagina pushes outside of the vaginal opening.