A 29-year-old nulliparous woman comes to the emergency department due to right-sided pelvic pain. The pain is sharp and began suddenly while she was shoveling snow this morning. It is accompanied by nausea and is worse with movement. The patient's last menstrual period was 2 weeks ago. Temperature is 37.8 C (100 F), blood pressure is 100/60 mm Hg, and pulse is 92/min. Pelvic ultrasound reveals a normal-sized uterus and left ovary; there is a right adnexal mass measuring 6 cm with absent blood flow to the right ovary. Urine β-hCG is negative. The patient's condition most likely arises from obstructed blood flow through which of the following ligaments?
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This patient's right-sided pelvic pain is consistent with ovarian torsion. Ovarian torsion is commonly precipitated by physical activity, and patients with complete torsion typically develop sudden onset, severe, unilateral lower abdominal pain with nausea/vomiting.
Ovarian torsion occurs because the ovary is loosely suspended posterolaterally to the uterus by the uteroovarian ligament and to the pelvic sidewall by the infundibulopelvic (IP) ligament (also known as the suspensory ligament of the ovary). The main risk factor for torsion is a large ovarian mass because weight of the mass causes the ovary to twist around the IP ligament, thereby occluding the ovarian vessels that run within the ligament. The torsed ovary then becomes edematous and ischemic due to lack of blood flow to the ovary. Diagnosis is clinical but pelvic ultrasound may help in evaluation.
(Choice A) The cardinal ligaments arise from the lateral pelvic sidewalls and attach to the cervix, vagina, and uterosacral ligaments to provide pelvic organ support. They are not in close proximity to the ovaries and are not involved in torsion.
(Choice C) The broad ligament is a wide sheet of peritoneal tissue that encapsulates the reproductive organs, attaching the uterus to the walls and floor of the pelvis; the mesosalpinx is the portion of the broad ligament that connects to the fallopian tubes (ie, the mesentery of the fallopian tubes).
(Choice D) The round ligament maintains the anteflexion of the uterus. It runs from the cornu of the uterus through the inguinal ring to the labia majora and is not connected to the ovaries. During pregnancy, a woman may experience intermittent, sharp pain due to the stretching round ligament.
(Choice E) The uterosacral ligaments connect the posterior aspect of the uterus to the anterior portion of the sacrum. These ligaments hold the uterus in position; loss of this support contributes to uterine prolapse into the vagina. They are not involved in the positioning or vascular supply of the ovaries.
Educational objective:
Ovarian torsion typically involves twisting of the infundibulopelvic ligament, often due to the weight of a large adnexal mass. The resulting occlusion of the blood supply to the ovary results in severe, acute pelvic pain and ovarian ischemia.