Anatomy clinical correlates Quiz: Ace Your Exams

A 15-year-old boy is brought to the emergency department because of severe abdominal pain, nausea, and vomiting. A few hours ago, he was playing basketball with his friends when he first developed mild abdominal pain. The pain increased gradually, and since then, the patient had increasing nausea and three episodes of vomiting. The patient has had similar, milder episodes in the past that resolved with rest. The review of systems is otherwise unremarkable. Past medical history is noncontributory. He is sexually active and uses condoms consistently. Temperature is 37.7°C (99.9°F), pulse is 95/min, respirations are 18/min, and blood pressure is 100/60 mmHg. Physical examination shows a soft, nontender, and nondistended abdomen. There is marked swelling, erythema, and tenderness of the right hemiscrotum. The pain is worsened when the right testis is elevated, and the scrotum does not transilluminate. Cremasteric reflex is absent on the right side. Physical examination of the left hemiscrotum and testis is unremarkable. Urinalysis is unremarkable. Which of the following is the most likely cause of this patient’s condition?