Question

Which one of the following is the most common extrauterine site to be affected by endometriosis?

• A. Vagina
• B. Rectovaginal septum
• C. Sigmoid colon
• D. Broad ligament (except tubes and ovaries)

Hint:

The ovary is the top site overall but is not an option here, so look for the next most frequent one.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
Endometriosis means endometrial-type tissue growing outside the uterus. The ovary is the single commonest site overall, but it is not offered as one of the choices here, so the question is really asking which of these four remaining sites is affected most often.

Step 2: Key Formula or Approach:
Textbooks rank the sites of endometriosis by how often implants are found there at surgery. After the ovaries, the next most frequently involved areas are the uterosacral ligaments, the pouch of Douglas, and the rectovaginal septum, followed by less common sites such as the sigmoid colon, the broad ligament, and, rarely, the vagina itself.

Step 3: Detailed Explanation:
The vagina is one of the least common sites for endometriosis, usually only involved when disease from the rectovaginal septum or the posterior fornix spreads into it directly.
The sigmoid colon can be involved, since it lies close to the pelvis, but bowel involvement overall is much less frequent than involvement of the ligaments and septa closer to the uterus.
The broad ligament, apart from the tube and ovary that sit within it, is affected less often than the rectovaginal septum in most surgical series.
The rectovaginal septum, lying between the back wall of the vagina and the front wall of the rectum, is one of the most frequently involved extrauterine sites, often felt as tender nodules on vaginal or rectal examination, right after the ovaries and the uterosacral ligament and pouch of Douglas group.

Step 4: Final Answer:
The answer line on this paper was left blank in the source, so this has been resolved using standard teaching. Among the listed choices, the rectovaginal septum is the most commonly affected extrauterine site, option (B).