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a circular or rounded flat plate; often spelled disc in names of anatomic structures.
articular disk a pad of fibrocartilage or dense fibrous tissue present in some synovial joints.
Bowman's disk one of the flat plates making up a striated muscle fiber.
choked disk papilledema.
ciliary disk pars plana.
embryonic disk (germ disk) (germinal disk) a flattened round bilaminar plate of cells in the blastocyst of a mammal, where the first traces of the embryo are seen; called also embryonic or germinal area.
herniated disk see herniated disk.
intervertebral disk the layer of fibrocartilage between the bodies of adjoining vertebrae; see also herniated disk.
intra-articular d's articular disk.
Merkel's d's small cup-shaped tactile receptors in the skin that are particularly sensitive to continuous pressure.
optic disk the intraocular part of the optic nerve formed by fibers converging from the retina and appearing as a pink to white disk in the retina; there are no sensory receptors in the region and hence no response to stimuli. Called also blind spot.
ruptured disk herniated disk.
slipped disk popular term for herniated disk.
A flattened, disklike region of cells from which the embryo begins to develop in the fertilized ovum of many vertebrate species. Also called blastodisk, embryonic disk.