Testicular torsion is a medical emergency that occurs when the spermatic cord, which supplies blood to the testicle, twists and cuts off its blood supply. This condition can cause severe pain and swelling in the affected testicle and usually requires immediate treatment to prevent permanent damage. Symptoms of testicular torsion include sudden, intense pain in one testicle, swelling, and sometimes nausea or vomiting. It most commonly affects males between the ages of 12 and 18 but can occur at any age. Prompt medical attention is crucial to restore blood flow and save the testicle.