Webster's New World Medical Dictionary

vertex
The top of the head. For example, in a ver-
tex presentation at birth, the top of the baby’s head
emerges first.
vertex birth
Birth in which the top of the baby’s
head emerges first. This is the most common 
presentation.
vertical
Upright, as opposed to horizontal. See
also Appendix B, “Anatomic Orientation Terms.”
vertical transmission
Passage of a disease-
causing agent (pathogen) from mother to baby dur-
ing the period immediately before and after birth.
Transmission might occur across the placenta, in
the breast milk, or through direct contact during or
after birth. For example, HIV can be a vertically
transmitted pathogen. Also known as perinatal
transmission.
vertigo
A feeling that one is turning around or
that things are turning about the person. Vertigo is
usually due to a problem with the inner ear. See also
dizziness; lightheadedness; unsteadiness.
vertigo, recurrent aural
See 
Ménière’s disease.
vesical
See 
bladder.
vesicant
A substance that causes tissue blistering.
Also known as vesicatory.
vesicate
To blister.
vesicatory
See 
vesicant.
vesicle 1
In dermatology, a tiny skin blister.
2
In anatomy, a small pouch.
vesicle, seminal
See 
seminal vesicle.
vesicoureteral reflux
The abnormal back flow
of urine from the bladder into the ureters toward
the kidneys. Abbreviated VUR. VUR is most com-
monly diagnosed during infancy and childhood and
can be due to a congenital dysfunction in the valve
where the ureter enters the bladder or to an
acquired blockage in the urinary tract. VUR does
not cause any pain or symptoms directly but is often
discovered because VUR leads to urinary tract infec-
tions (UTIs). Treatment can involve medications or
surgery. If not monitored carefully, ongoing reflux
and repeated UTIs can cause serious kidney injury
and possibly kidney failure.
vesicular
Referring to the presence of one or
more vesicles. For example, a vesicular rash fea-
tures small blisters on the skin.