What is "gubernaculum"

n. (context anatomy English) Either of a pair of folds of peritoneum that attach to the caudal end of the gonads (testes in males and ovaries in females).

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 in males and ovaries in females).

In nematodes, the gubernaculum is a hardened or sclerotized structure in the wall that guides the protrusion of the spicule during copulation. For example, in Caenorhabditis elegans, spicules serve to open and dilate the vagina of the female and the gubernaculum is a grooved plate in which the spicules move; the gubernaculum is controlled by two erector and two protractor muscles.

The shape and size of the gubernaculum are often important characters for the systematics of nematodes.