The purpose of this research study is to measure the muscles that make up your anal sphincter (muscles that control bowel movements) by using ultrasound. The most common way for women to injure these muscles is through childbirth. Some physicians think about 30% of women delivering their first baby develop some anal sphincter damage, which may or may not lead to symptoms such as anal urgency or incontinence (involuntary loss of gas or stool). The purpose of the study is to measure muscles in normal women who have never given birth or had an injury to their anal sphincter.

Participants will be asked to complete a one page questionnaire. This questionnaire will address whether perineal trauma, sphincter lacerations, anal incontinence, and fecal urgency impact the subject on any level. Subjects will also be asked about their bowel habits and history of problems with bowel movements. Subjects will then be asked to undergo an ultrasound study of the anal sphincter at the time of enrollment. Completing the entire study will take no more than 15 minutes. This will be done at the doctor's office. Answering the questionnaire will take no more than 5 minutes.

The endoanal ultrasound is a probe with a diameter equivalent to the index finger. It is inserted in the rectum and measures the length and width of the sphincter muscles.

Inclusion Criteria:

• nulliparous women over the age of 18.

Exclusion Criteria:

• any history of anal incontinence, chronic constipation, anorectal disease or trauma, neuromuscular or neuropsychiatric disease, diabetes, gastrointestinal disorders, or previous anorectal or pelvic surgeries.