Medical terms - Letter V (page 3) | MedicalVocabulary.org

Variation, observer

Failure by the observer to measure accurately, resulting in error. Observer variation may be due to the observer's missing a measurement, making an incorrect measurement, or misinterpreting data. Inter-observer…
Varicella (chickenpox)

A highly infectious viral disease, known familiarly as chickenpox. (In many countries, this disease is always called 'varicella.') Chickenpox has nothing at all to do with chicken. The name was meant to distinguish this…
Varicella immunization

See Chickenpox immunization
Varicella rash

Rash: Varicella (chickenpox) is characterized by a rash, often the first sign of the disease. The rash of chickenpox develops in crops with raised red spots arriving first, progressing to blisters that burst, creating…
Varicella vaccination

See Chickenpox immunization
Varicocele

A common scrotal condition characterized by elongation and enlargement of the network of veins leaving the testis which join to form the testicular vein. (This venous network is called the pampiniform plexus.) A…
Varicose vein

A dilated (widened) tortuous (twisting) vein, usually involving a superficial vein in the leg, often associated with incompetency of the valves in the vein. These visible and bulging veins are often associated with…
Varicose veins

Varicose veins: See: Varicose vein.
Varicosity

1. An enlarged and tortuous vein, artery, or lymphatic vessel. 2. Specifically, a varicose vein
Variola

The old practice of inoculating someone with the virus of smallpox to produce immunity to the disease. Lady Mary Wortley Montagu introduced this practice into England from Turkey in 1721. Unfortunately, the…
Variolation

The old practice of inoculating someone with the virus of smallpox to produce immunity to the disease. Lady Mary Wortley Montagu introduced this practice into England from Turkey in 1721. Unfortunately, the…
Varix

An enlarged and convoluted vein, artery or lymphatic vessel.
Varum

See: Varus
Varus

(vara, varum) Angled inward, bent or twisted inward, as in cubitus varus, hallux varus, talipes equinovarus, genu varum, and coxa vara
Vas deferens

The tube connecting the testes with the urethra. The vas deferens is a coiled duct that conveys sperm from the epididymis to the ejaculatory duct and the urethra
Vasa previa

A condition in which blood vessels within the placenta or the umbilical cord are trapped between the fetus and the opening to the birth canal, a situation that carries a high risk the fetus may die from hemorrhage due…
Vascular

Relating to the blood vessels of the body. The blood vessels of the body, as a group, are referred to as the vascular system. The blood vessels are composed of arteries, veins and capillaries -- arteries that pass…
Vascular bed

The vascular system, or a part thereof: for example, the pulmonary vascular bed describes the blood vessels of the lungs
Vascular dementia

A common form of dementia in older persons that is due to cerebrovascular disease, usually with stepwise deterioration from a series of small strokes and a patchy distribution of neurologic deficits affecting some…
Vascular endothelial growth factor (VEGF)

A substance made by cells that stimulates new blood vessel formation, a mitogen for vascular endothelial (vessel lining) cells. VEGF is a polypeptide structurally related to platelet-derived growth factor (PDGF). The…
Vascular headache

A group of headaches felt to involve abnormal sensitivity of the blood vessels (arteries) in the brain to various triggers which results in rapid changes in the artery size due to spasm (constriction). Other arteries in…
Vascular hemophilia

See: Von Willebrand disease
Vasculitis

Vasculitis: Plural: vasculitides. A general term for a group of diseases that feature inflammation of the blood vessels. Each of these diseases is defined by characteristic distributions of blood vessel involvement…
Vasculitis, allergic

Vasculitis, allergic: A disease (also more commonly called the Churg-Straus syndrome) characterized by inflammation of the blood vessels in persons with a history of asthma or allergy. The symptoms of the Churg-Strauss…
Vasculitis, retinal

Vasculitis, retinal: The retina is the portion of the eye that contains the nerves of sensation that perceive light. It is also filled with tiny blood vessels. Vasculitis of the eye is typically the result of…
Vasectomy

Vasectomy: A vasectomy is a surgical procedure designed to make a man sterile by cutting or blocking both the right and left vas deferens, the tubes through which sperm pass into the ejaculate.
Vasoconstriction

Narrowing of the blood vessels resulting from contracting of the muscular wall of the vessels. The opposite of vasodilation
Vasodepressor syncope

The temporary loss of consciousness in a particular kind of situation. (Syncope is temporary loss of consciousness or, in plain English, fainting). The situations that trigger this reaction are diverse and include…
Vasodilation

Widening of blood vessels resulting from relaxation of the muscular wall of the vessels. What widens is actually the diameter of the interior (the lumen) of the vessel. The opposite of vasoconstriction
Vasodilators

Agents that act as blood vessel dilators (vasodilators) and open vessels by relaxing their muscular walls. For example, nitroglycerin is a vasodilator. So are the ACE (angiotensin converting enzyme) inhibitors.
Vasomotor

Relating to the nerves and muscles that cause the blood vessels to constrict or dilate
Vasomotor rhinitis

Inflammation of the nose (rhinitis) due to abnormal neuronal (nerve) control of the blood vessels in the nose. Vasomotor rhinitis is not allergic rhinitis
Vasopressin

A relatively small (peptide) molecule that is released by the pituitary gland at the base of the brain after being made nearby (in the hypothalamus). Vasopressin has an antidiuretic action that prevents the production…
Vasovagal attack

See: Vasovagal reaction
Vasovagal reaction

A reflex of the involuntary nervous system that causes the heart to slow down (bradycardia) and that, at the same time, affects the nerves to the blood vessels in the legs permitting those vessels to dilate (widen). As…
Vasovagal syncope

The temporary loss of consciousness in a particular kind of situation (situational syncope) due to a vasovagal reaction. See also: Syncope
VATER association

A nonrandom association of birth defects. VATER is an mnemonic in which the letters V, A, T, E, and R each stand for one or more type of malformation. The VATER association has been extended and is now called the…
Vater, ampulla of

See: Ampulla of Vater
Vater, papilla of

See: Ampulla of Vater
VBAC

Vaginal Birth After Cesarian section. Although the abbreviation VBAC (pronounced VEE-back) does not appear in standard medical dictionaries, it is in active international use. VBAC has waxed and may wane in popularity…
VCJD

Stands for variant Creutzfeldt-Jakob disease, a human disease thought due to the same infectious agent as bovine spongiform encephalopathy (BSE), or mad cow disease. Both the human and bovine disorders are invariably…
VCU

Voiding cystourethrography. Or voiding cystourethrogram
VCUG

Voiding cystourethrography. Or voiding cystourethrogram
VDRL test

A blood test for syphilis (VDRL stands for Venereal Disease Research Laboratory) that detects an antibody that is present in the bloodstream when a patient has syphilis. A negative (nonreactive) VDRL is compatible with…
Vector

In medicine, a vector is a carrier. The best way to understand a vector is to recall its origin as a word. Vector is the Latin word for a 'bearer.' In parasitology (the study of parasitic organisms), the vector carries…
Vector, cloning

A DNA molecule originating from a virus, a plasmid (see below) or the cell of a higher organism into which another DNA fragment can be integrated without loss of the vector's (carrier's) capacity for self-replication…
Vectrin

Brand name for minocycline
VEGF

Vascular endothelial growth factor, a substance made by cells that stimulates the formation of new blood vessels, a process called angiogenesis. VEGF also acts as a mitogen for vascular endothelial (vessel lining)…
Vein

A blood vessel that carries blood low in oxygen content from the body back to the heart. The deoxygenated form of hemoglobin (deoxyhemoglobin) in venous blood makes it appear dark. Veins are part of the afferent wing of…
Vein of Galen aneurysm

A congenital malformation of blood vessels of the brain. Specifically, an arteriovenous (AV) malformation in which blood shunts from cerebral arteries into a dilated vein of Galen (an internal cerebral vein). In…