fornices

Fornices, or fornix (plural fornices), is a term used in anatomy to refer to two distinct structures depending on context: a brain structure and vaginal recesses.

In neuroanatomy, the fornices are paired C-shaped bundles of white matter that serve as major output pathways of the hippocampus. They originate from the fimbria of the hippocampus, converge to form the crura of the fornix, join to create the body, and continue as the columns that descend toward and terminate in the mammillary bodies and other diencephalic structures. Functionally, the fornices connect the hippocampus with the mammillary bodies, thalamic nuclei (notably the anterior nucleus), hypothalamic areas, and septal regions, contributing to memory and limbic circuitry such as the Papez circuit. Clinically, disruption of the fornix can impair episodic memory and memory consolidation; lesions may result from tumors, hydrocephalus, trauma, or nutritional deficiencies affecting the thalamus or hippocampus.

In the female reproductive tract, the vaginal fornices are recesses formed around the cervix by the vaginal walls: the anterior fornix, posterior fornix, and two lateral fornices. They constitute potential spaces within the upper vagina. The posterior fornix lies closest to the rectouterine pouch (Douglas pouch) and is a common site for cul-de-sac fluid collection and pelvic examination; the lateral fornices contact the pelvic sidewalls and peritoneal reflections. These spaces are clinically relevant during pelvic examination, imaging, and the assessment of pelvic pathology.