| germinal disk | Germ disk, the point in a telolecithal ovum where the embryo begins to be formed. Synonym: embryonic disk, germinal area, area germinativa. (05 Mar 2000) |
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| Merkel's tactile disk | A specialised tactile sensory nerve ending in the epidermis, characterised by a terminal cuplike expansion of an intraepidermal axon in contact with the base of a single modified keratinocyte. Synonym: meniscus tactus, Merkel's corpuscle, Merkel's tactile cell, Merkel's tactile disk, tactile disk. (05 Mar 2000) |
| choked disk | papilloedema |
| micrometre disk | <microscopy> A glass disk engraved with a suitable scale, used at the diaphragm of a micrometre ocular. The scale to be focused by the eye lens has to be seen in the field of view. Micrometre eye piece. (05 Aug 1998) |
| ciliary disk | The darkly pigmented posterior zone of the ciliary body continuous with the retina at the ora serrata. Synonym: ciliary disk, ciliary ring, pars plana. Origin: Mod. L. (05 Mar 2000) |
| ruptured disk | <orthopaedics> A condition that results in the abnormal protrusion (bulging), herniation or prolapse of a vertebral disc from its normal position in the vertebral column. The displaced disc may exert force on a nearby nerve root causing the typical neurologic symptoms of radiating pain (to an extremity), numbness, tingling and weakness. Recurrent episodes of severe back pain are common. Treatment includes non-steroidal anti-inflammatory drugs, corticosteroids and rest. More advanced cases may require surgical intervention (for example laminectomy, micro-disc surgery). (17 Dec 1997) |
| Placido da Costa's disk | <instrument> An instrument marked with lines or circles by means of which the corneal reflex can be observed. Synonym: Placido da Costa's disk. Origin: kerato-+ G. Skopeo, to examine (05 Mar 2000) |
| porous disk | <chemistry> A disk in a tube connecting two different solutions in a voltaic cell that allows ion flow without extensive mixing of the solutions, similar to a salt bridge. (09 Jan 1998) |
| hair disk | A richly innervated area of skin around a hair follicle, consisting of a thickened layer of epithelial cells in which ramify unmyelinated terminals of a single axon. (05 Mar 2000) |
| cuttlefish disk | A circle of paper or thin plastic coated with ground cuttlefish bone; used, when attached to a mandrel and rotated by a dental handpiece, for fine smoothing and finishing of dental materials and tooth. (05 Mar 2000) |
| H disk | <cell biology> The H band is an area within muscle tissue which is light when stained and consists only of myosin fibres (and no actin fibres). The H band is at the centre of each muscle sarcomere. (09 Oct 1997) |
| prolapsed disk | A condition that results in the abnormal protrusion (bulging), herniation or prolapse of a vertebral disc from its normal position in the vertebral column. The displaced disc may exert force on a nearby nerve root causing the typical neurologic symptoms of radiating pain (to an extremity), numbness, tingling and weakness. Recurrent episodes of severe back pain are common. Treatment includes non-steroidal anti-inflammatory drugs, corticosteroids and rest. More advanced cases may require surgical intervention (for example laminectomy, micro-disc surgery). (27 Sep 1997) |
| proligerous disk | A mass of epithelial cells surrounding the ovum in the ovarian follicle. Synonym: discus proligerus, ovigerus, proligerous disk, proligerous membrane. Origin: NA (05 Mar 2000) |
| Hensen's disk | <cell biology> The H band is an area within muscle tissue which is light when stained and consists only of myosin fibres (and no actin fibres). The H band is at the centre of each muscle sarcomere. (09 Oct 1997) |
| herniated disk | <orthopaedics> A condition that results in the abnormal protrusion (bulging), herniation or prolapse of a vertebral disc from its normal position in the vertebral column. The displaced disc may exert force on a nearby nerve root causing the typical neurologic symptoms of radiating pain (to an extremity), numbness, tingling and weakness. Recurrent episodes of severe back pain are common. Treatment includes non-steroidal anti-inflammatories, corticosteroids and rest. More advanced cases may require surgical intervention (for example laminectomy, micro-disc surgery). (27 Sep 1997) |