Fornix

In anatomy, a vaultlike or arched structure. "Fornix" is the Latin word for "vault or arch." The fornix in the brain is a fibrous arching band connecting the two lobes of the cerebrum. The fornix of the conjunctivae refers to loose arching folds connecting the conjunctival membrane lining the inside of the eyelid with the conjunctival membrane covering the eyeball. The fornix of the vagina refers to the anterior (front) and posterior (back) recesses into which the upper vagina is divided. These vaultlike recesses are formed by protrusion of the cervix into the vagina. . "Fornix" is closely related to "fornication." It seems that prostitutes in ancient Rome used to hang out under the arches of certain public buildings. The act of carrying on an illicit sexual relationship consequently came to be called "going under the arches": fornication.

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1. [TA] In general, an arch-shaped structure; often the arch-shaped roof (or roof portion) of an anatomic space. 2. [TA] The compact, white fiber bundle by which the hippocampus of each cerebral hemisphere projects to the contralateral hippocampus and to the septum, anterior nucleus of the thalamus, and mamillary body. Arising from pyramidal cells of Ammon horn, the fibers of the f. form the alveus hippocampi and the fimbria hippocampi, and in their further course compose, sequentially, the commissure of the f. [TA], also called the hippocampal commissure [TA] (commissura hippocampi [TA]), the crus of f. [TA] (crus fornicis [TA]), the body of f. [TA] (corpus fornicis [TA]), and the column of f. [TA] (columna fornicis [TA]), which divides into a smaller portion of precommissural fibers [TA] that pass anterior to the anterior commissure to the septal area and a larger portion of postcommissural fibers [TA] that pass posterior to the anterior commissure to end mainly in the mammillary nuclei and to a lesser extent in the anterior thalamic nucleus. SYN: trigonum cerebrale. SYN: cerebral trigone. [L. arch, vault]

- f. conjunctivae SYN: conjunctival f..

- conjunctival f. [TA] the space formed by the junction of the bulbar and palpebral portions of the conjunctiva, that of the upper lid being the superior conjunctival f. and that of the lower lid, the inferior conjunctival f.. SYN: conjunctival cul-de-sac, f. conjunctivae, retrotarsal fold.

- f. gastricus [TA] SYN: f. of stomach.

- f. of lacrimal sac [TA] f. of the lacrimal sac; the upper, blind end of the lacrimal sac that extends above the openings of the lacrimal canaliculi. SYN: f. sacci lacrimalis [TA].

- pharyngeal f. SYN: vault of pharynx.

- f. pharyngis [TA] SYN: vault of pharynx.

- f. sacci lacrimalis [TA] SYN: f. of lacrimal sac.

- f. of stomach [TA] formerly considered to be a synonym of the official Nomina Anatomica term “fundus of stomach” (used more commonly than fundus in radiology), Terminologia Anatomica lists f. and fundus of stomach separately, considering that all stomachs have a fundus, being the uppermost portion of the body of the stomach, the mucosa of which includes the greatest density of fundic cells; f. is now reserved for the domed or pocket-like portion of the stomach that lies superior to and to the left of the cardial orifice, in which, in the upright position, gas is often contained. SYN: f. gastricus [TA].

- transverse f. SYN: commissura fornicis.

- f. uteri SYN: vaginal f..

- f. vaginae [TA] SYN: vaginal f..

- vaginal f. [TA] the recess at the vault of the vagina; it is divided into an anterior part, posterior part, and lateral part with respect to its relation to the cervix of the uterus. The posterior part is clinically significant as the site for culdocentesis and culdoscopy. The proximity of the ureter (below) and the uterine artery (above) adjacent to the lateral f. is important clinically. SYN: f. vaginae [TA], f. uteri.

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for·nix 'fȯr-niks n, pl for·ni·ces -nə-.sēz an anatomical arch or fold: as

a) the vault of the cranium

b) the part of the conjunctiva overlying the cornea

c) a body of nerve fibers lying beneath the corpus callosum with which they are continuous posteriorly and serving to integrate the hippocampus with other parts of the brain

d) the vaulted upper part of the vagina surrounding the uterine cervix

e) the fundus of the stomach

f) the vault of the pharynx

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n. (pl. fornices)

an arched or vaultlike structure, especially the fornix cerebri, a triangular structure of white matter in the brain, situated between the hippocampus and hypothalamus. The fornix of the vagina is any of three vaulted spaces at the top of the vagina, around the cervix of the uterus.

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for·nix (forґniks) pl. forґnices [L. “arch”] an archlike anatomical structure or the vaultlike space created by such a structure. [TA] fornix of brain: the efferent pathway of the hippocampus, projecting chiefly to the mammillary bodies and habenular nuclei; each fornix of the pathway is an arched tract that is united under the corpus callosum with the other fornix, so that together they comprise two columns, a body, and two crura.