A 16 year old boy presents to the ER of the children's hospital complaining of severe onset testicular pain of one hour duration. He played a game of soccer several hours ago, but there is no reported injury or trauma. He is experiencing nausea and vomiting. There is no fever, dysuria, or discharge. The patient is not sexually active. You examine the affected testis, which is asymmetric from the other side, and it appears to be attached to the inner lining of the scrotum higher than usual. He says it feels tender. The cremaster reflex is absent. A blood count shows leukocytosis. This boy needs immediate surgery.
Challenge: What is the diagnosis?
1. What is the cremaster reflex?
*Note: I have been told that you should not say "acute scrotum" out loud.