The primary urethral groove or urethral groove is a temporary linear indentation on the underside (ventral side) of the male

penis A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''pen ...

during embryonic development. In humans, it typically appears around eight weeks of gestation and becomes closed into a normal

male urethra The urethra (: urethras or urethrae) is the tube that connects the urinary bladder to the urinary meatus, through which placental mammals urinate and ejaculate. The external urethral sphincter is a striated muscle that allows voluntary contro ...

by the twelfth week.

Clinical significance

Failure of complete closure can be associated with

hypospadias Hypospadias is a common malformation in fetal development of the penis in which the urethra does not open from its usual location on the head of the penis. It is the second-most common birth defect of the male reproductive system, affecting about ...

References

{{DEFAULTSORT:Urethral Groove Embryology of urogenital system Human penis