focal distance

distance /dis·tance/ (dis´tins) the measure of space intervening between two objects or two points of reference.

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focal distance  that from the focal point to the optical center of a lens or the surface of a concave mirror.

interarch distance  the vertical distance between the maxillary and mandibular arches under certain specified conditions of vertical dimension.

interocclusal distance  the distance between the occluding surfaces of the maxillary and mandibular teeth with the mandible in physiologic rest position.

interocular distance  the distance between the eyes, usually used in reference to the interpupillary distance.

working distance  the distance between the front lens of a microscope and the object when the instrument is correctly focused.

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focal distance

n.

See focal length.

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focal

1. limited to a small area or volume.

2. pertaining to or emanating from focus.

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focal distance

see focal-film distance.

focal length

the distance between the lens and an object from which all rays of light are brought to a focus.

focal liver disease

widely disseminated micro-abscesses or abscesses, migration paths of helminth larvae.

focal macular melanosis

dark colored spots on the skin, not elevated above the skin surface but apt to be confused with melanosis.

focal myelitis-encephalitis

widely disseminated inflammatory lesions, usually the result of blood-borne infection, in brain and spinal cord.

focal symmetrical encephalomalacia

see focal symmetrical encephalomalacia.

focal symmetrical spinal poliomalacia

see focal symmetrical spinal poliomalacia.

focal ulcerative dermatitis

manifest by ulcers in the unfeathered anterior breast skin of 4 to 5 months old male turkeys. The incidence is influenced by litter type. Called also breast buttons.

focal zone

in ultrasound, the area of the transducer where the sound beam is most sharply focussed and where the area under examination will give the best image.