Testicular torsion occurs when a testicle rotates, twisting the spermatic cord that brings blood to the scrotum. The reduced blood flow causes sudden and often severe pain and swelling.

During testicular torsion a testicle rotates, twisting the spermatic cord that brings blood to the scrotum, the loose bag of skin under the penis that contains the testicles. The reduced blood flow causes sudden and often severe pain and swelling.
Testicular torsion is most common between ages 12 and 18, but it can occur at any age, even before birth.
Testicular torsion usually requires emergency surgery. If treated quickly, the testicle can usually be saved. But when blood flow has been cut off for too long, a testicle might become so badly damaged that it has to be removed.
Signs and symptoms of testicular torsion include:
Young boys who have testicular torsion typically wake up due to scrotal pain in the middle of the night or early in the morning.
Seek emergency care for sudden or severe testicle pain. Prompt treatment can prevent severe damage or loss of your testicle if you have testicular torsion.
You also need to seek prompt medical help if you've had sudden testicle pain that goes away without treatment. This can occur when a testicle twists and then untwists on its own (intermittent torsion and detorsion). Surgery is frequently needed to prevent the problem from happening again.
Testicular torsion occurs when the testicle rotates on the spermatic cord, which brings blood to the testicle from the abdomen. If the testicle rotates several times, blood flow to it can be entirely blocked, causing damage more quickly.
It's not clear why testicular torsion occurs. Most males who get testicular torsion have an inherited trait that allows the testicle to rotate freely inside the scrotum. This inherited condition often affects both testicles. But not every male with the trait will have testicular torsion.
Testicular torsion often occurs several hours after vigorous activity, after a minor injury to the testicles or while sleeping. Cold temperature or rapid growth of the testicle during puberty also might play a role.
Testicular torsion can cause the following complications:
Having testicles that can rotate in the scrotum is a trait inherited by some males. If you have this trait, the only way to prevent testicular torsion is surgery to attach both testicles to the inside of the scrotum.