optic disk

disk (disk) a circular or rounded flat plate. Spelled also disc.

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articular disk  a pad of fibrocartilage or dense fibrous tissue present in some synovial joints.

Bowman's disks  flat, disklike plates making up striated muscle fibers.

choked disk  papilledema.

ciliary disk  the thin part of the ciliary body.

contained disk  protrusion of a nucleus pulposus in which the anulus fibrosus remains intact.

cupped disk  a pathologically depressed optic disk.

extruded disk  herniation of the nucleus pulposus through the anulus fibrosus, with the nuclear material remaining attached to the intervertebral disk.

gelatin disk  a disk or lamella of gelatin variously medicated, used chiefly in eye diseases.

growth disk  epiphyseal plate.

Hensen's disk  H band.

herniated disk  herniation of intervertebral disk; see under herniation.

intervertebral disks  layers of fibrocartilage between the bodies of adjacent vertebrae.

intra-articular disks  fibrous structures within the capsules of diarthrodial joints.

noncontained disk  herniation of the nucleus pulposus with rupture of the anulus fibrosus.

optic disk  the intraocular part of the optic nerve formed by fibers converging from the retina and appearing as a pink to white disk; because there are no sensory receptors in the region, it is not sensitive to stimuli.

Discus opticus (optic disk).

Placido's disk  a disk marked with concentric circles, used in examining the cornea.

protruded disk , ruptured disk herniation of intervertebral disk; see under herniation.

sequestered disk  a free fragment of the nucleus pulposus in the spinal canal outside of the anulus fibrosus and no longer attached to the intervertebral disk.

slipped disk  popular term for herniation of an intervertebral disk; see under herniation.

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optic disk

n.

The small, circular, optically insensitive region in the retina containing no rods or cones, where fibers of the optic nerve emerge from the eyeball. Also called blind spot, optic papilla.

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Optic disk

The small area in the retina where the optic nerve enters the eye that is not sensitive to light. Also called the blind spot.

Mentioned in: Retinal Vein Occlusion

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disk [disk]

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.

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optic

of or pertaining to the eye.

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optic chiasma

see optic chiasm.

optic cortex

see visual cortex.

optic cup activity

see intraretinal space.

optic disk

the disk in the fundus of the eye marking the point at which the optic nerve enters; it is accompanied by blood vessels, is oval, light in color and the blind spot of the retina.

optic nerve

the second cranial nerve; it is purely sensory and is concerned with carrying impulses for the sense of sight. The rods and cones of the retina are connected with the optic nerve which leaves the eye slightly to the nasal side of the center of the retina. The point at which the optic nerve leaves the eye is called the blind spot because there are no rods and cones in this area. The optic nerve passes through the optic foramen of the skull and into the cranial cavity. It then passes backward and undergoes a division; those nerve fibers leading from the nasal side of the retina cross to the opposite side in the optic chiasma while those from the temporal side continue to the thalamus uncrossed. The nerve tracts proceeding backward from the optic chiasm, pass around the cerebral peduncle, and dividing into a lateral and medial root, which end in the superior colliculus and lateral geniculate body, respectively. After synapsing in the thalamus the neurons convey visual impulses to the occipital lobe of the brain.

Injury to the nerve leads to partial or complete loss of sight on the opposite side. Commonly bilateral.

optic nerve aplasia

an uncommon congenital anomaly, most frequently seen in Collie dogs; affected animals are blind from birth. Hypovitaminosis A and prenatal infection with bovine virus diarrhea are possible causes.

optic nerve inflammation

optic neuritis.

optic primordia

the eyes begin in the embryo as a pair of shallow optic grooves on each side of the developing forebrain. The grooves form optic vesicles which invaginate to form a double-walled optic cup.

optic radiation

fibers from the lateral geniculate body entering the occipital cortex.

optic stalk

the evagination from the neural tube of the developing embryo which develops the optic cup at its extremity; the stalk persists as the optic nerve.

optic sulcus

see optic groove.

optic vesicle

the initial evagination from the neural tube which gives rise to the optic cup and the optic stalk.