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Cremasteric reflex

The cremasteric reflex is a cutaneous reflex observed in human males.

This reflex is elicited by lightly stroking the superior and medial part of the thigh.[1] The normal response is a contraction of the cremaster muscle that pulls up the scrotum and testis on the side stroked.

More specifically, the reflex utilizes sensory and motor fibers of the L1 spinal nerve. When the inner thigh is stroked, sensory fibers of the ilioinguinal nerve are stimulated. These synapse in the spinal cord and activate the motor fibers of the genital branch of the genitofemoral nerve which causes the cremaster muscle to contract and elevate the testis.

In children, this reflex may be exaggerated, and this can lead to the mistaken diagnosis of undescended testes.

Upper and lower motor neuron disorders, as well as a spine injury of L1-L2, can cause an absence of the cremasteric reflex. It has also been reported to be absent in 100% of cases of testicular torsion, making it a useful sign in this difficult diagnosis.

Urban legends

According to the Straight Dope, it is a classic urban legend that Sumo wrestlers raise their testicles in preparation for training and/or combat.[2] While it may be possible to do this via the pubococcygeal muscle or acquired control over the cremaster muscle, it is not practiced by Sumo wrestlers today and Sumo does not allow contact with this region. Although it was once used in sumo wrestling when sumo wrestlers were trained from early childhood into adulthood, it is not used in modern sumo wrestling.


  1. ^ Definition: cremasteric reflex from Online Medical Dictionary. Retrieved on 2007-12-06.
  2. ^ The Straight Dope: Can sumos retract their testicles inside their bodies?. Retrieved on 2007-12-06.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Cremasteric_reflex". A list of authors is available in Wikipedia.
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