| Genital tubercle | |
|---|---|
 Stages in the development of the external sexual organs in the male and female. | |
| Details | |
| Precursor | somatopleure[1] |
| Gives rise to | genital swelling, mons pubis, clitoris, penis |
| System | Reproductive system |
| Identifiers | |
| Latin | tuberculum phallicum; tuberculum genitale |
| TE | tubercle_by_E5.7.4.0.1.0.1 E5.7.4.0.1.0.1 |
| Anatomical terminology | |
A genital tubercle or phallic tubercle is a body of tissue present in the development of the reproductive system. It forms in the ventral, caudal region of mammalian embryos of both sexes, and eventually develops into a primordial phallus. In the human fetus, the genital tubercle develops around week 4 of gestation, and by week 9 becomes recognizably either a clitoris or penis. This should not be confused with the sinus tubercle which is a proliferation of endoderm induced by paramesonephric ducts. Even after the phallus is developed (either a penile shaft or clitoral shaft),[2] the term genital tubercle remains, but only as the terminal end of it,[3] which develops into either the glans penis or the glans clitoridis.
In the development of the male fetus, the two sides of the tubercle approach ventrally forming a hollow tube that encloses the male urethra. The two glans wings merge in the midline forming the septum glandis.[4] In the female fetus, the tubercle is attached to the vestibular folds that remain unfused forming the labia minora and the vaginal vestibule in between.[5] The genital tubercle is sensitive to dihydrotestosterone and rich in 5-alpha-reductase, so that the amount of fetal testosterone present after the second month is a major determinant of phallus size at birth.