A Endometriotic lesions occur in 1–20% of all women, the majority of which present symptomatically and are diagnosed with the condition.

B As well as occurring throughout the pelvis, the umbilicus, abdominal wound scars, the vagina, bladder, rectum and lungs may be involved.

C Endometriosis in the pelvis is probably a result of retrograde menstruation.

D More distant foci may result from mechanical, lymphatic or blood-borne spread.

E Retrograde menstruation is uncommon and when it occurs is always associated with endometriosis.

F None of the above.