A 14 year old boy has been brought to the ER by his mother in severe pain radiating from his scrotum to his inguinal area. His p
ulse is 122, and he has vomited twice prior to arriving at the hospital. His scrotum is red and swollen, and his testicles are tender to palpation. There is extensive cremaster muscle contraction. Which of the following is the most likely diagnosis?
