Dartos muscle of scrotum

The dartos muscle is the scrotal part of the dartos fascia, composed by smooth cells.

In the scrotum, the tunica dartos acts to regulate the temperature of the testicles, which promotes spermatogenesis. It does this by expanding or contracting to wrinkle the scrotal skin.

• Contraction reduces the surface area available for heat loss, thus reducing heat loss and warming the testicles.
• Conversely, expansion increases the surface area, promoting heat loss and thus cooling the testicles.

The dartos muscle works in conjunction with the cremaster muscle to elevate the testis but should not be confused with thecremasteric reflex.