Encyclopedia of Health and Medicine

V–Z
VACTERL The acronym for a constellation of
BIRTH DEFECTS that tend to occur in coincidence
with each other. Doctors consider a baby who has
three or more of the defects to have the VACTERL
association, and will examine the baby closely for
the other defects in the constellation. These
defects include
• V: vertebral (spinal) anomalies
• A: ANAL ATRESIA (also called imperforate ANUS)
• C: cardiac (HEART) anomalies
• T/E: tracheoesophageal fistula (may also occur
as tracheal fistula and ESOPHAGEAL ATRESIA)
• R: renal (kidney) anomalies
• L: limb anomalies
Occurring often enough that some doctors
believe it, too, is part of the constellation, is a single-ARTERY
UMBILICAL CORD (the normal umbilical
cord has two arteries), which sometimes appears
in the acronym as a final S (VACTERLS). VAC-
TERL occurs sporadically (in a nonhereditary pattern);
researchers do not know what causes it, nor
do they understand the connections among the
various defects. Some of the birth defects can be
life threatening, such as the HEART malformation
tetralogy of Fallot (a complex of four serious heart
defects). Treatment, often surgery, attempts to correct
the congenital anomalies.
See also CONGENITAL ANOMALY; CONGENITAL HEART
DISEASE.
vagina The muscular passageway between the
CERVIX and the VULVA (outside of the body). The
vagina serves as the portal through which the
menstrual flow leaves the body with
MENSTRUATION, the erect PENIS enters during SEXUAL
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INTERCOURSE, and the FETUS passes during
CHILDBIRTH.
The outer structures of the vagina are strong
muscles that have the ability to vary the inner
diameter of the vagina from its normal state in
which the vaginal walls touch each other to four
or five inches to accommodate the birth of a child.
Deep folds of mucous membrane (the vaginal
mucosa) line the vagina. The folds, called rugae,
give the vagina its ability to expand. The vaginal
muscles also relax to extend the depth (length) of
the vagina, facilitating SEXUAL INTERCOURSE.
The vaginal tissue near the opening of the
vagina (the vaginal introitus) has an abundance of
sensory NERVE endings though the rest of the vaginal
mucosa has few sensory nerve endings. A
small ring of vaginal mucosa, called the hymen,
extends partially across the opening of the vagina.
The degree to which the hymen restricts access to
the vagina varies widely among women. Though
conventional wisdom purports that penetration of
the erect penis with a woman’s first experience of
sexual intercourse tears or ruptures the hymen,
this may or may not be the case. A hymen that
does not extend very far across the vaginal opening
may not impede the entry of the erect penis.
The hymen may also rupture or tear as a result of
other factors such as insertion of tampons or activities
such as horseback riding.
The Bartholin’s glands and Skene’s ducts near
the entrance to the vagina and the nabothian
glands (cervical glands) that cover the cervix provide
secretions to moisten and lubricate the interior
of the vagina. These secretions diminish with
the loss of ESTROGENS that characterizes MENOPAUSE.
As a result the vaginal mucosa becomes thin and
fragile and the vagina less flexible after
menopause.