Sinus tubercle (also known as sinual tubercle or Müllerian eminence) is the proliferation of

endoderm Endoderm is the innermost of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and mesoderm (middle layer). Cells migrating inward along the archenteron form the inner layer of the gast ...

induced by the paramesonephric ducts. It is located in the developing fetus between the orifices of the

mesonephric ducts The mesonephric duct (also known as the Wolffian duct, archinephric duct, Leydig's duct or nephric duct) is a paired organ that forms during the embryonic development of humans and other mammals and gives rise to male reproductive organs. Struc ...

on the

urogenital sinus The urogenital sinus is a part of the human body only present in the development of the urinary and reproductive organs. It is the ventral part of the cloaca, formed after the cloaca separates from the anal canal during the fourth to seventh we ...

. The uterovaginal primoridium, which is a fusion of the caudal ends of paramesonephric ducts, contacts the dorsal wall of the

and, induces the formation of the sinus tubercle. This occurs in both sexes: *In the female the

mesonephric duct The mesonephric duct (also known as the Wolffian duct, archinephric duct, Leydig's duct or nephric duct) is a paired organ that forms during the embryonic development of humans and other mammals and gives rise to male reproductive organs. Stru ...

loses all association with the gonad and, disappears. The sinus tubercle then gives rise to the sino-vaginal bulbs and, when it later becomes solid it is referred to as the vaginal plate. It likewise gives rise to the

hymen The hymen is a thin piece of mucosal tissue that surrounds or partially covers the external vaginal opening. It forms part of the vulva, or external genitalia, and is similar in structure to the vagina. In children, a common appearance of the ...

, which eventually breaks down in most cases. * In the males, the sinus tubercle gives rise to the

seminal colliculus The seminal colliculus (Latin ''colliculus seminalis''), or verumontanum, of the prostatic urethra is a landmark distal to the entrance of the ejaculatory ducts (on both sides, corresponding vas deferens and seminal vesicle feed into correspond ...

References

* *Moore Persaud, ''Medical embryology'' 2003 {{Development of urinary and reproductive systems Animal developmental biology Embryology