| PVD | patient very disturbed; peripheral vascular disease; portal vein dilation; posterior vitreous detach... |
|---|---|
| VBG | vagotomy and Billroth gastroenterostomy; venous blood gases; venous bypass graft; vertical-banded ga... |
| VPO | velopharyngeal opening; vertical pendular oscillation |
| VSO | vertical supranuclear ophthalmoplegia |
| VVAS | vertical visual analog scale |
| vertical hymen | A hymen in which the opening is perpendicular. (05 Mar 2000) |
|---|---|
| vertical illumination | <microscopy> Bright field illumination by light from the objective which is reflected or scattered from the (usually opaque) object. Illumination is by means of a vertical illuminator placed above the objective. Light is brought into a side tube and directed toward the back aperture of the objective by a tiny mirror or prism, or else by a full-aperture transparent-reflector (thin glass plate) 45[macron] to the axis of the bodytube. (05 Aug 1998) |
| vertical index | The relation of the height to the length of the skull: (height × 100)/length. Synonym: height-length index, length-height index, transversovertical index. (05 Mar 2000) |
| vertical instability | <radiobiology> A type of magnetohydrodynamic (n=0) instability where the plasma drifts vertically upward. Nearly all tokamaks are vertically unstable (all highly shaped ones are). Controlling this instability is possible in many cases, and is an important facet of machine design. Vertical instabilities give rise to halo effects. (09 Oct 1997) |
| vertical muscle of tongue | An intrinsic muscle of the tongue, consisting of fibres that pass from the aponeurosis of the dorsum to the aponeurosis of the inferior surface; action, decreases the superior to inferior dimension of (flattens) the tongue; nerve supply, hypoglossal for motor, lingual for sensory. Synonym: musculus verticalis linguae. (05 Mar 2000) |
| vertical nystagmus | An up-and-down oscillation of the eyes. (05 Mar 2000) |
| vertical opening | The length of the face determined by the distance of separation of jaws. Occlusal vertical dimension (ovd or vdo) or contact vertical dimension is the lower face height with the teeth in centric occlusion. Rest vertical dimension (vdr) is the lower face height measured from a chin point to a point just below the nose, with the mandible in rest position. (12 Dec 1998) |
| vertical osteotomy | An oral surgical procedure similar to sliding oblique osteotomy. (05 Mar 2000) |
| vertical overlap | The extension of the upper teeth over the lower teeth in a vertical direction when the opposing posterior teeth are in contact in centric occlusion, the distance that teeth lap over their antagonists vertically, especially for the distance that the upper incisal edges drop below the lower ones, but may also describe the vertical relations of opposing cusps, the relationship of the maxillary incisors to the mandibular incisors when the incisal edges pass each other in centric occlusion. Synonym: overbite. (05 Mar 2000) |
| vertical parallax | The relative vertical displacement of the image when each eye is closed in turn; seen in vertical diplopia, or heterophoria. (05 Mar 2000) |
| vertical plate | Flat portion of a bone which lies within or closely approximates a vertical plane. See: perpendicular plate of ethmoid bone, perpendicular plate of palatine bone. Synonym: lamina perpendicularis, pars perpendicularis, vertical plate. (05 Mar 2000) |
| vertical retraction syndrome | <syndrome> A retraction of the globe and pseudoptosis on attempted adduction; due to co-innervation of the horizontal recti. Sometimes there is an inability to abduct the affected eye (type 1), or adduct the affected eye (type 2), or both (type 3). Synonym: Duane's syndrome. (05 Mar 2000) |
| vertical strabismus | A form of strabismus in which the visual axis of one eye deviates upward (s. Sursum vergens) or downward (s. Deorsum vergens). (05 Mar 2000) |
| vertical transmission | <microbiology> Transmission of a pathogen such as HIV from mother to foetus or baby during pregnancy or birth. See: perinatal transmission. (09 Oct 1997) |
| vertical vertigo | Dizziness experienced when standing upright. (05 Mar 2000) |