Mullerian ducts in a male fetus. Uterus masculinus
Keywords: mullerian, male, female equine, uterus, masculinus
In males, the Wollfian (mesonephric) tubule system develops into the ducti deferentia, epididymides and gubernaculae. In the presence of testicles, inhibin (produced by Sertoli cells) suppresses the development of what would otherwise be female genitals. Although the female (Mullerian or paramesonephric) system is suppressed, remnants are sometimes visible in the neonate or even adult animals.
In this case (a 315 day old equine fetus) thread-like remnants of the mullerian system are clearly visible. Occasionally this structure is referred as the uterus masculinus.
Image size: 3243x 2190px. Copyright: Dr Frederico Canisso. canisso@illinois.edu