Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «F»:
Fornix: In anatomy, a vaultlike or arched structure.
The fornix in the brain -- a fibrous arching band connecting the two lobes of the cerebrum.
The fornix of the conjunctivae -- loose arching folds connecting the conjunctival membrane lining the inside of the eyelid with the conjunct...
Fornix cerebri: An arching fibrous band in the brain connecting the two lobes of the cerebrum. (The cerebrum is the largest part of the brain and consists of two hemispheres separated by a deep longitudinal fissure). Each fornix -- there are two -- in the brain is an arched tract of nerves.
Fornix conjunctivae: 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.
In anatomy, a vaultlike or arched structure. "Fornix" is the Latin word for "vault or arch."...
Fornix uteri: The fornix of the uterus 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. The fornix uteri is also known as the fornix vaginae (the vaginal fornix).
Fornix vaginae: See: Vaginal fornix....
Founder effect: The positive effect on gene
frequency when a population (a colony) has only a small number of
original settlers (founders) one
or more of whom had that gene. For example, the gene for Huntington
disease was introduced
into the Lake Maracaibo region in Venezuela early in the 19th
Four-finger crease: See: Simian crease....
Four-finger line: See: Simian crease....
Fournier's gangrene: A horrendous infection of the genitalia that causes severe pain in the genital area (in the penis and scrotum or perineum) and progresses from erythema (redness) to necrosis (death) of tissue. Gangrene can occur within hours. The mortality (death) rates are up to 50%.
In this m...
Fourth cranial nerve
Fourth cranial nerve: The fourth cranial nerve, the
trochlear nerve, is the nerve supply to the superior oblique muscle
of the eye, one of the muscles that moves the eye. Paralysis of the
trochlear nerve results in rotation of the eyeball upward and outward
(and, therefore, double vision).
Fourth disease: A disorder characterized by a rash due to a toxin produced by Staphylococcus aureus (Staph aureus bacteria).
Measles and scarlet fever were differentiated from one another in the 17th century. Rubella was accepted as the third distinct pediatric exanthem (rash) in 1881. What were th...
Fourth stage of labor
Fourth stage of labor: The hour or two after
delivery when the tone of
the uterus is established and the uterus contracts down again
expelling any remaining contents. These contractions are hastened by
breast-feeding, which stimulates production of the hormone
Fourth ventricle: One cavity in a system of four communicating cavities within the brain that are continuous with the central canal of the spinal cord.
The four ventricles consist of two lateral ventricles, the third ventricle and the fourth ventricle:
Lateral ventricles: The lateral ventricles ar...
Fovea: In the eye, a tiny pit located in the macula of the retina that provides the clearest vision of all. Only in the fovea are the layers of the retina spread aside to let light fall directly on the cones, the cells that give the sharpest image. Also called the central fovea or fovea centralis.
Fovea centralis: See: Fovea. ...