The paired gubernacula (from Ancient Greek κυβερνάω = pilot, steer) also called the caudal genital ligament, are embryonic structures which begin as undifferentiated mesenchyme attaching to the caudal end of the gonads (

testes A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoste ...

in males and

ovaries The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...

in females).

Structure

The gubernaculum is present only during the

development of the reproductive system The development of the reproductive system is the part of embryonic growth that results in the sex organs and contributes to sexual differentiation. Due to its large overlap with development of the urinary system, the two systems are typically ...

. It is later replaced by distinct vestiges in males and females.The gubernaculum arises in the upper abdomen from the lower end of the gonadal ridge and helps guide the testis in its descent to the inguinal region.

Males

* The upper part of the gubernaculum degenerates. * The lower part persists as the

gubernaculum testis In the inguinal crest of a peculiar structure, the gubernaculum testis makes its appearance. This is at first a slender band, extending from that part of the skin of the groin which afterward forms the scrotum through the inguinal canal to the bod ...

(" scrotal ligament"). This ligament secures the testis to the most inferior portion of the scrotum, tethering it in place and limiting the degree to which the testis can move within the scrotum. * Cryptorchidism (undescended testes) are observed in ''INSL3''-null male mice. This implicates

INSL3 Insulin-like 3 is a protein that in humans is encoded by the ''INSL3'' gene. Function The protein encoded by this gene is an insulin like hormone produced mainly in gonadal tissues in males and females. Studies of the mouse counterpart sugge ...

as a key hormone in the growth and differentiation of the gubernaculum to allow transabdominal migration. Higher testicular temperatures associated with cryptorchidism is associated with reduced fertility.

Females

* The gubernaculum has two vestigial remnants in females, the

ovarian ligament The ovarian ligament (also called the utero-ovarian ligament or proper ovarian ligament) is a fibrous ligament that connects the ovary to the lateral surface of the uterus. Structure The ovarian ligament is composed of muscular and fibrous tissu ...

and the

round ligament of the uterus The round ligament of the uterus is a ligament that connects the uterus to the labia majora. Structure The round ligament of the uterus originates at the uterine horns, in the parametrium. The round ligament exits the pelvis via the deep inguina ...

(''ligamentum teres uteri'') which respectively serve to support the ovaries and uterus in the pelvis. * Development of the gubernaculum in female mice overexpressing ''INSL3'' causes descended ovaries and reduced fertility. This ovarian descent is more pronounced by the additional administration of dihydrotestosterone, which suppresses development of the cranial suspensory ligament. Therefore, maintenance of the cranial suspensory ligament prevents abdominal translocation of the ovaries.Adham et al., Mol Endocrinol 2002, 16, 244-252

Development

As the

scrotum The scrotum or scrotal sac is an anatomical male reproductive structure located at the base of the penis that consists of a suspended dual-chambered sac of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum co ...

and

labia majora The labia majora (singular: ''labium majus'') are two prominent longitudinal cutaneous folds that extend downward and backward from the mons pubis to the perineum. Together with the labia minora they form the labia of the vulva. The labia majo ...

form in males and females respectively, the gubernaculum aids in the descent of the gonads (both testes and ovaries). The testes descend to a greater degree than the

and ultimately pass through the

inguinal canal The inguinal canals are the two passages in the anterior abdominal wall of humans and animals which in males convey the spermatic cords and in females the round ligament of the uterus. The inguinal canals are larger and more prominent in males. ...

into the

. The mechanism of this movement is still debated.

History

The gubernaculum was first described by John Hunter in 1762. The term comes from

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

meaning to steer, pilot or the

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally air or water). On an aircraft the rudder is used primarily to counter adve ...

or helm.

References

External links

* - "Inguinal Region, Scrotum and Testes: The Scrotal Ligament" {{Development of urinary and reproductive systems Abdomen Embryology of urogenital system