Cremasteric Reflex

The cremasteric reflex is a superficial reflex that can be exceptionally useful in assessing testicular emergencies. The cremasteric reflex is a contraction of the cremaster muscle, in response to the stroking of the thigh, which results in retraction of the testicle. Absence of the reflex is an ominous sign when assessing an acute scrotum.

When assessing an acute scrotum, the most important condition to rule out is testicular torsion (Ringdahl & Teague 2006). Testicular torsion occurs when the testicle rotates within the scrotum, the twisting out the epididymis results in impaired blood flow, ischemia can ensue rapidly, and can eventually result in loss of the testicle (Ringdahl & Teague 2006).

Testicular torsion usually occurs in the absence of trauma, and without precipitating factors; although an abnormal attachment of the testicle to the scrotum "bell clapper" deformity, present in approximately 10% of males, puts an individual at increased risk. The overall incidence of testicular torsion is estimated at 1 per 4000 in males under age 25, with the highest incidence occurring during the first few days of life, and from age 12-18yrs. (EBMedicine, Ringdahl & Teague 2006). Testicular torsion requires emergency urology referral, as ischemia begins within 4 hours (Ringdahl & Teague 2006). It is precisely for this reason that knowing how to assess for a cremasteric reflex is essential.




When assessing an acute scrotum for testicular torsion one testicle may appear to be shortened due to the twisting of the epididymis, cremasteric reflex may be absent on this side, but the test should be performed bilaterally. To assess cremasteric reflex the thigh should be stroked with a finger, the handle of a reflex hammer, or most commonly with the blade of a tongue depressor. A normal finding is a retraction of at least 0.5 cm; an abnormal, or absent reflex needs immediate referral.





The cremasteric reflex, in the presence of scrotal pain has been estimated at 96-99% sensitive (Ringdahl & Teague 2006, Schmitz & Safranek, 2009); which is to say that the probability of having a false negative is approaching zero percent. Absent reflex is 66-88% specific for torsion, yielding a negative predictive value of 96% (EBMedicine). The caveat to these probabilities is that an absent cremasteric reflex can be considered normal in approximately 50% of infants under the age of 30 months (Ringdahl & Teague 2006). The importance of the high sensitivity from the nursing perspective is that we can be relatively certain that the odds of a false negative are low, and that there will likely be need for urgent referral of these patients.


Correction, or de-torsion of a testicle, can be performed manually with local or procedural sedation; however it is generally addressed through emergent surgical exploration and intervention. Salvage rates are time dependent: surgery within six hours is 90% successful in salvaging the testicle, successful salvage drops to 50% by hour 12, and less than 10% after 24 hours (Ringdahl & Teague 2006). For this reason there is a low threshold for referral and diagnostic studies.

As a nurse knowing how to assess cremasteric reflexes can be exceptionally useful because, in the presence of scrotal pain, an absent creamasteric reflex approaches 100% sensitivity for testicular torsion. Given the short window for surgical intervention, the risks of over-triage, or over treatment due to a false positives are far outweighed by the potential benefit that patients with testicular torsion will experience from rapid referral and intervention.

The cremasteric reflex is a low barrier, easily performed physical assessment. It is a highly sensitive screening tool for patients who need immediate physician attention and surgical referral.




Ringdahl, E., & Teague, L. (2006). Testicular Torsion. American Family Physician, 74(10).

Schmitz, D., & Safranek, S. (2009). How useful is a physical exam in diagnosing testicular torsion?. Clinical Inquiries, 2009 (MU).

EB Medicine Topics (EB Medicine Topics)., 
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