<qa>  What is the most common problem in women who have sustained injury to the muscles of the back passageInjury to the muscles of the back passage anal canal is a relatively common problem. This injury can result in problems with bowel control later in life and usually occurs during vaginal childbirth commonly referred to as 3rd and 4th degree perineal tears. Currently women who have sustained injury to the muscles of the back passage undergo an ultrasound scan by inserting a probe 3 to 4 cms into the back passage. This helps to check if the muscle of the back passage has healed i.e is intact or has a defect. The investigators would like to establish whether a 3D ultrasound scan probe placed outside the vagina can identify the defects and hence avoid inserting the probe into the back passage. In addition to getting the above information using 3D ultrasound scan, the investigators would also like to identify injuries to the pelvic floor muscle levator ani in these patients. Which can be diagnosed using the 3D ultrasound probe placed outside the vagina perineum. Women who sustain injury to this muscle are known to develop prolapse later on in life. 