| Genital tubercle | |
|---|---|
Stages in the development of the external sexual organs in the male and female.
| |
| Details | |
| Precursor | Somatopleure[1] |
| Gives rise to | Clitorisorpenis |
| 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 | |
Agenital tubercle, phallic tubercle, or clitorophallic structure[2] is a body of tissue present in the development of the reproductive systemofamniotes.[3] 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 four of gestation, and by week nine, becomes recognizably either a clitorisorpenis. 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 shaftorclitoral shaft),[4] the term genital tubercle remains, but only as the terminal end of it,[5] 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.[6] 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.[7] 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.
