Fabella - diminutive of Latin faba = a bean, hence, a sesamoid bone found in the lateral head of gastrocnemius.

Facet - Latin facies = face, hence a small smooth bony surface, either coated with articular cartilage or the site of a tendinous attachment (cf. a facet on a diamond).

Facilitate - Latin facilis = easy, hence, to make easy.

Falciform - adjective, Latin falx = a sickle, and forma = form, hence, shaped like a sickle.

Falx - Latin = sickle, hence, the sickle-shaped falx cerebri and falx cerebelli, adjective - falciform.

Familial polyposis - Hereditary, autosomal dominant precancerous syndrome characterized by innumerable adenomatous polyps of the colon.

Fanconi anemia (congenital pancytopenia) - A rare congenital anemia characterized by pancytopenia and hypoplasia of the bone marrow.

Fascia - Latin = band or bandage, hence the fibrous wrapping of muscles - deep fascia, or the subcutaneous layer of fatty connective tissue - superficial fascia, adjective, fascial. Fascia, a connective tissue, is the packing material of the body. It envelopes the muscles, bones and joints and holds us together supporting the body structure and giving us our shape. Fascia organizes and separates: it provides protection and autonomy for the individual muscles and viscera. It joins and bonds these separate entities and establishes spatial relationships. Chemically it is the collagen in the fascia that enables it to change.

Fasciculus - diminutive of Latin fascis = bundle, hence, a bundle of nerve or muscle fibres.

Fastigius - Latin fastigium = summit, hence the peak of the 4th ventricle, adjective - fastigial.

Fauces - Latin = throat, adjective - faucial.

Female reproductive system - consists of the ovaries, uterine tubes, uterus (womb), vagina (birth canal), and vulvae.

Femoris - (L. femur, thigh). Pertaining to the femur or thigh.

Femur - Latin = thigh, adjective - femoral.

Fenestra - Latin = window.

Fertilization - The process of union of two gametes whereby the somatic chromosome number is restored and the development of a new individual is initiated.

Fetus - An unborn or unhatched vertebrate especially after attaining the basic structural plan of its kind; specifically : a developing human from usually three months after conception to birth. The developing mammal in utero; in Man, after the 2nd month in utero, adjective - foetal or fetal.
 
Fibre - Latin fibra = a fibre, adjective, Latin fibrosus = fibrous.

Fibril - diminutive of Latin fibra = a fibre.

Fibroblast - A connective-tissue cell of mesenchymal origin that secretes proteins and especially molecular collagen from which the extracellular fibrillar matrix of connective tissue forms.

Fibrosis - Refers to the presence of scar tissue or collagen fibers in any tissue. In the liver, fibrosis or scarring of the liver damages the architecture and thus the functionality of the organ. Fibrosis, combined with the liver's ability to regenerate, causes cirrhosis (regeneration within the scar tissue).

Fibula - Latin = brooch, which the tibia and fibula resemble, the fibula representing the movable pin, adjective - fibular.

Filament - Latin filamentum = a delicate fibre, adjective - filamentous.

Filum - Latin = a thread. Filum terminale - a thread of pia continuous with the lower end of the spinal cord.

Fimbria - Latin = a fringe, hence, fimbria hippocampi, a scalloped band of fibres alongside the hippocampus.

Fissure - Latin = a cleft.

Fistula - In medicine, a fistula is an abnormal channel that creates an open passageway between two bodily structures that do not normally connect.

Fixator - Latin fixus = fixed, hence, a muscle which fixes a part.

Flaccid - adjective, Latin flaccidus = weak or slack.

Flagella - structure that protrudes from the cell membrane and makes wavelike movements. Classified by length and number per cell, flagella are long and few. A single flagellum propels sperm. Structurally flagella consists of microtubules arranged in a "9 + 2" array.

Flagellum - A long tapering process that projects singly or in groups from a cell and is the primary organ of motion of many microorganisms.

Flavum - adjective, Latin flavus = yellow.

Flex - Latin flexum = bent, hence, flexor, a muscle which bends a part of the body, and flexion = the act of flexing.

Flexor - (L. flectere, to bend). A muscle that, upon contraction tends to bend a joint; the antagonist of an extensor.

Flexure - Latin flexura = a bending.

Flocculus - diminutive of Latin floccus, a tuft. Hence resembling a picture of a little cloud, with a woolly top and a flat base, as in flocculus cerebelli.

Flow cytometry - Analysis of biological material by detection of the light-absorbing or fluorescing properties of cells or subcellular fractions such as chromosomes passing in a narrow stream through a laser beam. Flow cytometry is used with automated sorting devices to sort successive droplets of the stream into different fractions depending on the fluorescence emitted by each droplet.

Foetus - the developing mammal in utero; in Man, after the 2nd month in utero, adjective - foetal or fetal.

Folia - plural of Latin folium = leaf.

Follicle - Latin folliculus = a little bag, adjective - follicular.

Fontanelle - French diminutive of Latin fons = fountain, associated with the palpable pulsation of the brain in the anterior fontanelle of an infant.

Foramen - Latin = hole.
 
Foramen magnum - The opening in the skull through which the spinal cord passes to become the medulla oblongata.

Forceps - Latin = tongs.

Forearm - the upper limb between the elbow and the wrist.

Formed element - cells and cell fragments present in blood.

Fornix - Latin = arch (hence fornication, because the Roman prostitutes plied their profession beneath the arches of the bridges over the river Tiber).

Fossa - Latin = a ditch or trench, hence a concavity in bone, or an organ, or on a lining surface.

Fovea - Latin = a pit (usually smaller than a fossa).

Foveola - diminutive of fovea.

Free radicals - An atom or a group of atoms with an unpaired electron. Radicals are unusually reactive, strongly oxidizing species capable of causing a wide range of biological damage.

Freestanding facility - A diagnosing or treatment facility which is not owned by a hospital and owns/maintains it's own patient records.

Frenulum - diminutive of frenum.

Frenum - Latin = bridle or curb.

Frontal - adjective, Latin frontis = of the forehead, or coronal.

Frontal (coronal) plane - divides the body or organ vertically into a front and rear part.

Fulguration - Destroying tissue using an electric current.

Fundiform - adjective, Latin fundus = bottom or base (cf. fundamental), hence, sling-shaped.

Fundus - Latin = bottom or base. (But note that the fundus of the stomach and uterus are at the top, and the fundus of the eye and of the bladder are posterior!).

Funiculus - diminutive of Latin funis = cord (used usually for bundles of nerve fibres).

Fusiform - adjective, Latin fusus = spindle, hence, spindle-shaped.