Testicular torsion happens when a testicle twists on the spermatic cord, cutting off its blood supply; the main underlying cause is usually a congenital (in‑born) anatomical issue that lets the testicle move too freely in the scrotum.

What Causes Testicular Torsion?

The Core Problem: Twisting of the Spermatic Cord

Testicular torsion occurs when the testicle rotates and twists the spermatic cord, the bundle that carries blood vessels to the testicle.

This twist blocks blood flow, and if not fixed quickly, the testicle can become permanently damaged or die.

Think of it like an apple twisting on its stem: if it turns far enough, the stem kinks and blood flow stops.

Main Underlying Cause: Bell-Clapper Deformity

In most cases, the root cause is a congenital anatomical variant called bell‑clapper deformity.

  • The testicle is not firmly attached to the inner wall of the scrotum, so it hangs and can swing and rotate more freely.
  • Because it is “free floating” in the tunica vaginalis, the spermatic cord can twist inside, leading to intravaginal torsion.
  • This deformity often affects both testicles, increasing bilateral risk.

Other anatomical risk factors include:

  • Horizontal lie of the testicle (lying sideways instead of vertical).
  • Longer-than-normal intrascrotal segment of the spermatic cord.
  • Failure of the testis to be well attached within the scrotum in pre‑adolescent and adolescent boys.

Triggers vs True Causes

Doctors often separate the predisposing cause (the anatomy) from triggers that can provoke an actual torsion event.

Common Triggers

Even with bell‑clapper anatomy, torsion may only happen when something sets it off:

  • Sudden movement or exertion (running, sports, vigorous activity).
  • Exercise such as bicycle riding, which can jostle the testicles.
  • Minor trauma to the scrotum (a hit or bump), though only about 4–8% of cases are due to trauma.
  • It can also occur spontaneously during sleep or while at rest, with no clear trigger.

Not Always a Clear Reason

In many patients, especially teens, torsion just appears “out of the blue” with severe sudden pain, even when they are simply sitting or sleeping.

Experts emphasize that it is often not clear why the twisting happens at that particular moment, even if the anatomic risk is present.

Age, Genetics, and Other Risk Factors

While testicular torsion can technically happen at any age, there are patterns in who is most at risk.

  • Most cases occur in males younger than 25, especially adolescents.
  • Some males have an inherited trait that allows the testicle to rotate more freely inside the scrotum, increasing torsion risk.
  • Prior episode of torsion (even if it “untwisted” on its own) raises the risk of it happening again if the testicle is not surgically fixed.
  • Cryptorchidism (undescended testicle) is associated with a significantly higher risk of torsion.

Torsion in Babies and Newborns

Testicular torsion can also occur before birth or shortly after a baby is born.

  • In fetal or neonatal torsion, the issue may be that the protective sac around the testicle does not attach properly to the scrotum, allowing the entire testicle and sac to twist (extravaginal torsion).
  • This can lead to a firm, discolored scrotum in the newborn and often requires urgent evaluation.

Pathophysiology: What Happens Inside?

Once the spermatic cord twists, a cascade of events begins:

  1. Mechanical twist of the spermatic cord suspending the testis.
  2. Venous blood flow is blocked first, because veins are easier to compress.
  3. Venous congestion increases pressure, which then reduces arterial inflow.
  4. Loss of oxygen supply leads to testicular ischemia and, if not treated, infarction (tissue death).

The damage progresses faster if the testicle rotates multiple times and if blood flow is completely blocked.

This is why torsion is treated as a true emergency , often requiring surgery within hours to save the testicle.

Mini FAQ: Common Questions People Ask in Forums

“Can tight underwear or crossing my legs cause testicular torsion?”

  • Normal underwear, leg crossing, or everyday movements are not considered proven causes on their own.
  • However, in someone with bell‑clapper anatomy, random movements or minor jostles can be enough to trigger a twist.

“Can masturbation or sex cause it?”

  • Medical sources generally focus on exercise, movement, or trauma rather than sexual activity specifically.
  • Torsion can happen during any activity, including sex, but the underlying issue is the freely rotating testis, not the act itself.

“Is it my fault if I get torsion?”

  • No. The primary cause is usually an in‑born anatomical setup that you cannot control.
  • What matters most is recognizing sudden severe testicular pain and getting emergency care quickly.

When to Worry (Very Important)

If you or someone else suddenly develops:

  • Sudden, severe testicular or scrotal pain.
  • Swelling, redness, or a high‑riding testicle.
  • Pain with nausea or vomiting.

This should be treated as an emergency and evaluated immediately in an ER or urgent care, not watched at home.

“Latest News” and “Forum Discussion” Angle

Recent patient‑education resources and medical reviews (through 2025–2026) continue to stress that testicular torsion is often under‑recognized by young men and parents, leading to delayed treatment.

Online forums and social platforms frequently feature stories where individuals ignored pain for hours or days, only to learn later that earlier care might have saved the testicle, which has fueled renewed awareness campaigns about sudden testicular pain as an emergency sign.

Bottom line:
When people ask “what causes testicular torsion,” the medical answer is: an in‑born anatomical setup (often bell‑clapper deformity) that lets the testicle twist on its cord, sometimes triggered by movement, exercise, or trauma—but often without any clear trigger at all.

Information gathered from public forums or data available on the internet and portrayed here.