Labia: Latin for
lips. There are two pairs of labia (lips) at the entrance to
the vagina. They are the labia majora (the larger outside
pair) and the labia minora (the smaller inside pair). Together
they form part of the vulva (the female external genitalia).
Labia majora: The larger (major) outside pair of labia (lips) of
the vulva (the female external genitalia).
Labia minora: The smaller (minor) inside pair of labia (lips) of
the vulva (the female external genitalia).
Labial: Pertaining to the lips.
Labium: A lip. Labium is the singular of the Latin neuter noun
meaning "a lip." The plural is labia.
Labor: The journey of the baby and placenta (afterbirth) from
the uterus to the vagina to the outside world. Synonymous with
childbirth, confinement, delivery, parturition, and travail (the
French word for work).
Labyrinth: The maze of canals in the inner ear. The labyrinth is
the portion of the ear that is responsible for sensing balance.
Inflammaton of the labyrinth (labyrinthitis) can be accompanied
Labyrinthitis: Inflammation of the labyrinth.
Laceration: Severed skin. A cut. Washing a cut or scrape with
soap and water and keeping it clean and dry is all that is
required to care for most wounds. Putting alcohol, hydrogen
peroxide, and iodine into a wound can delay healing and should
be avoided. Seek medical care early if you think that you might
need stitches. Any delay can increase the rate of wound
infection. Any puncture wound through tennis shoes has a high
risk of infection and should be seen by your healthcare
professional. Any redness, swelling, increased pain, or pus
draining from the wound may indicate an infection that requires
Lacrimal: Pertaining to tears.
Lacrimation: Shedding tears.
Lactase: Enzyme that breaks down the milk sugar lactose.
Lactase deficiency: Lack of the enzyme lactase resulting in
failure to digest lactose in milk (lactose intolerance).
Lactation: Giving milk.
Lactobacillus: Literally milk bacteria, normally found in the
mouth, intestinal tract and vagina.
Lactobacillus acidophilus: Bug that produces acidophilus milk.
Lactose intolerance: inability to digest the milk sugar lactose.
Lacuna: A small pit, cavity, defect or gap.
Lamella: A thin leaf, plate, disk, wafer.
Lamina: A plate or layer. For example, the lamina arcus
vertebrae, usually just called the lamina, are plates of bone in
each vertebral body.
Lancet: Small pointed knife used to do a finger prick for a
blood test. Also the name of a medical journal in England.
Lanugo: The fine hair on the body of a newborn baby.
Laparoscopy: Laparoscopy is a type of surgery where small
incisions are made in the abdominal wall through which
instruments are placed that can help in visualizing structures
in the abdomen and pelvis.
Laparotomy: An operation to open the abdomen.
Large cell carcinoma: A group of lung cancers in which the cells
are large and look abnormal.
Large intestine: Comes after the small intestine. Large because
it is wider than the small intestine.
Laryngeal: Having to do with the larynx.
Laryngeal papilloma: A warty growth in the larynx, ususally on
the vocal cords. Persistent hoarseness is a common symptom.
Laryngeal papillomatosis: Numerous warty growths on the vocal
cords. Most common in young children. Recurrences are,
unfortunately, frequent. Remission may occur after several
years. The disease can be due to the baby contracting human
papilloma virus (HPV) during birth through the vaginal canal
from a mother with genital warts (which are due to HPV). Each
year, about 300 infants are born with the virus on their vocal
cords because of maternal transmission.
Laryngectomee: A person who has had his or her voice box
Laryngectomy: An operation to remove all or part of the larynx.
Laryngitis: Inflammation of the larynx (voice box).
Laryngomalacia: A soft floppy larynx.
Laryngoscope: A flexible, lighted tube used to examine the
Laryngoscopy: Examination of the larynx with a mirror (indirect
laryngoscopy) or with a laryngoscope (direct laryngoscopy).
Laryngostasis: More commonly known as croup. An infection of the
larynx, trachea, and the bronchial tubes, largely in children.
Caused usually by viruses, less often by bacteria. Symptoms
include a cough that sounds like a barking seal and a harsh
crowing sound during inhaling. Treatment can include moist air,
salt water nose drops, decongestants and cough suppressants,
pain medication, fluids, and occasionally antibiotics. The major
concern in croup is breathing difficulty as the air passages
narrow. Close monitoring of the breathing of a child with croup
is important, especially at night. While most children recover
from croup without hospitalization, some children can develop
life-threatening breathing difficulties. Therefore, close
contact with the doctor during this illness is important.
Larynx: The larynx is the portion of the breathing, or
respiratory, tract containing the vocal cords which produce
vocal sound. It is located between the pharynx and the trachea.
It is also called the "voice box." Its outer wall of cartilage
forms the area of the front of the neck referred to as the
Laser: A powerful beam of light used in some types of surgery to
cut or destroy tissue.
Lateral: The side of the body or body part that is farther from
the middle or center (median) of the body. Typically, lateral
refers to the outer side of the body part, but it is also used
to refer to the side of a body part. For example, when referring
to the knee, lateral would mean the side of the knee that is
farthest from the opposite knee. The opposite of lateral is
Lavage: Washing out. Gastric lavage is washing out the stomach,
for example, to remove drugs or poisons.
Lazy eye: An eye that diverges in gaze. More formally called
strabismus. Can be esotropia (cross-eyed) or exotropia
lb.: The abbreviation for pound, the measure of weight, lb.
(plural: lb. or lbs.) stands for "libra" (Latin for pound).
LDL: Low-density lipoprotein.
LDL cholesterol: Low-density lipoprotein cholesterol (the "bad"
Lead poisoning: An environment hazard (for example, from
lead-containing paint, leaded gasoline,etc) capable of causing
Legg-Perthes disease: A hip disorder in children due to
interruption of the blood supply to the head of the femur (the
ball in the ball-and-socket hip joint). Also called Legg disease
and Legg-Calve-Perthes disease.
Legionaire's disease: A disease (first identified at the 1976
American Legion convention) due to bacteria (Legionella) found
in plumbing, shower heads and water-storage tanks. Outbreaks of
Legionella pneumonia have been attributed to evaporative
condensors and cooling towers.
Legionella: The bacteria causing Legionaire's disease.
Leiomyoma: A benign tumor of smooth muscle, the type of muscle
found in the heart and uterus. A leiomyoma of the uterus is
commonly called a fibroid.
Leiomyosarcoma: a malignant tumor of smooth muscle origin.
Smooth muscle is the major structural component of most hollow
internal organs and the walls of blood vessels. Can occur almost
anywhere in the body but is most frequent in the uterus and
gastrointestinal tract. Complete surgical excision, if possible,
is the treatment of choice.
Leishmania: A group of parasites causing considerable human
Leishmaniasis: Diseases due to Leishmania involving the organs (kala-azar),
skin plus mucous membranes (espundia), or skin alone (usually
named for the place plus boil, button or sore as, for example,
Jericho boil, Bagdad button, Dehli sore).
Lennox syndrome: See Lennox-Gastaut syndrome.
Lennox-Gastaut syndrome: A severe form of epilepsy that usually
begins in early childhood and is characterized by frequent
seizures of multiple types, mental impairment, and a particular
brain wave pattern (a slow spike-and-wave pattern). The seizures
that are notoriously hard to treat and may lead to falls and
injuries can be reduced in frequency by treatment with
lamotrigone, a chemically novel antiepileptic drug. The syndrome
is named for W.G. Lennox and H. Gastaut who described it.
Leprosy: A skin infection caused by a bacteria, which can also
be associated with nerve damage. The bacteria involved is called
Lesbian: Female homosexual. The name "lesbian" comes from the
Greek island of Lesbos in the Aegian Sea where in antiquity the
women were said to be homosexual. The poet Sappho who lived on
Lesbos (circa 600 BC) was a lesbian in both geographic location
and sexual orientation.
Lesbianism: Female homosexuality. Also called sapphism (after
the lesbian poet Sappho).
Lesion: An area of abnormal tissue change.
Lethargy: Abnormal drowsiness, stupor.
Leucemia: See leukemia.
Leukemia: Cancer of the blood cells.
Leukemia, accelerated phase of: Refers to chronic myelogenous
leukemia that is progressing. The number of immature, abnormal
white blood cells in the bone marrow and blood is higher than in
the chronic phase, but not as high as in the blast phase.
Leukemia, smoldering: A condition in which the bone marrow does
not function normally. It does not produce enough blood cells.
This condition may progress and become acute leukemia.
Smoldering leukemia also is called myelodysplastic syndrome or
Leukemoid reaction: A benign blood picture resembling leukemia.
For example, in infectious mononucleosis.
Leuko-: Prefix meaning white.
Leukocytes: Cells that help the body fight infections and other
diseases. Also called white blood cells (WBCs).
Leukocyte count: A white blood cell (WBC) count.
Leukocytosis: Increase in the number of white blood cells.
Leukodystrophy: Disorder of the white matter of the brain. The
white matter mainly consists of nerve fibers (not the nerve
cells themselves) and is concerned with conduction od nerve
Leukopenia: Shortage of white blood cells.
Leukoplakia: A white spot or patch in the mouth.
Levo-: From the Latin laevus meaning on the left side. For
example, a molecule that shows levorotation is turning or
twisting to the left. The opposition of levo- is dextro- (from
the Latin dexter meaning on the right side) so the opposite of
levorotation is dextrorotation.
Levocardia: Reversal of all of the abdominal and thoracic organs
(situs inversus) except the heart which is still in its usual
location on the left. This situation is far more of an anatomic
mess than when all the organs including the heart are reversed
to create a complete mirror image. Levocardia virtually always
results in congenital heart disease (malformation of the heart
or great vessels).
LHRH agonists: Compounds that are similar to LHRH (luteinizing
Libido: The word "libido" in Latin means "desire, longing,
fancy, lust, or rut." Although the adjective "libidinous"
meaning lustful has been used in English for 500 or so years,
"libido" made a belated entry into the English language in1913,
thanks to Sigmund Freud and other psychoanalysts who applied the
term to psychic energy or drive, especially the sexual instinct.
Library: In genetics, a library is an unordered collection of
clones (i.e., cloned DNA from a particular organism), whose
relationship to each other can be established by physical
mapping. For example, you can have an E. coli library or a human
DNA library. Among the types of libraries, there are genomic
libraries and arrayed libraries. (See Library, genomic and
Library, arrayed: In genetics, arrayed libraries of DNA clones
are used for many purposes, including screening for a specific
gene or genomic region of interest as well as for physical
mapping. An arrayed library consists of (in technical terms)
individual primary recombinant clones (which are hosted in
phage, cosmid, YAC, or another vector) that have been placed in
two-dimensional arrays in microtiter dishes (plastic dishes with
an orderly array of tiny wells). Each primary clone can be
identified by the identity of the plate and the clone location
(row and column) on that plate. The information gathered on
individual clones from various genetic linkage and physical map
analyses is then entered into a relational database and used to
construct physical and genetic linkage maps.
Library, genomic: A collection of DNA clones made from a set of
randomly generated overlapping DNA fragments representing the
entire genome of an organism. As a molecular genetic sequel to
John Steinbeck’s "Of Mice and Men", today you can have a mouse
genomic library or a human genomic library.
Li-Fraumeni syndrome: A family tendency to cancers due to a
mutation in a gene that normally serves to curb cancer: the p53
Ligament: A ligament is a band or sheet of connective tissue
that connects two bones together.
Ligate: To tie. As, for example, the surgeon ligated the artery.
Ligature: Material (silk, gut, wire, etc) used to ligate.
Limb: The arm or leg.
Lingual: Having to do with the tongue.
Linkage: Tendency for genes to be inherited together because of
their location near one another on the same chromosome.
Linkage analysis: Study aimed at establishing linkage between
genes. Today linkage analysis serves as a way of gene-hunting
and genetic testing.
Linkage map: A map of the genes on a chromosome based on linkage
analysis. A linkage map does not show the physical distances
between genes but rather their relative positions, as determined
by how often two gene loci are inherited together. The closer
two genes are (the more tightly they are linked), the more often
they will be inherited together. Linkage distance is measured in
Lipid: Fatty substance.
Lipid storage diseases: A series of disorders due to inborn
errors in lipid metabolism resulting in the abnormal
accumulation of lipids in the wrong places (Examples include
Gaucher, Fabry and Niemann-Pick diseases and metachromatic
Lipid profile: Pattern of lipids in the blood. (A lipid profile
usually includes the total cholesterol, high density lipoprotein
(HDL) cholesterol, triglycerides, and the calculated low density
lipoprotein (LDL) cholesterol.
Lipoma: A benign fatty tumor.
Lipoprotein: A complex of lipid and protein, the way lipids
travel in the blood.
Lips: Aside from the lips of the mouth, there are two pairs of
lips at the entrance to the vagina. They are the labia majora
(the larger outside pair) and the labia minora (the smaller
inside pair). Together they form part of the vulva (the female
Listeria: A group of bacteria named after the English surgeon
and apostle of antisepsis, Joseph Lister (1827-1912).
Listeriosis: Infection with one of the Listeria bacteria capable
of causing miscarriage (spontaneous abortion), stillbirth and
Litho-: Prefix meaning stone.
Lithotomy: Surgical removal of a stone.
Lithotripsy: Procedure to break a stone into small particles
that can be passed in the urine.
Liver: An organ in the upper abdomen that aids in digestion and
removes waste products and worn-out cells from the blood.
Livid: Black and blue.
Living will: A living will is one form of advance medical
directive. Advance medical directives preserve the person’s
right to accept or reject a course of medical treatment even
after that person becomes mentally or physically incapacitated
to the point of being unable to communicate those wishes. There
are two basic types of advance directives: (1) a living will, in
which the person outlines specific treatment guidelines that are
to be followed by health care providers; (2) a health care proxy
(also called a power of attorney for health-care
decision-making) in which the person designates a trusted
individual to make medical decisions in the event that he or she
becomes too incapacitated to make such decisions. Advance
directive requirements vary greatly from one jurisdiction to
another and should therefore be drawn up in consultation with an
attorney who is familiar with the laws of the particular
jurisdiction. (This entry is based upon material from the
National MS Society).
Lobar: Having to do with a lobe. For example, lobar pneumonia.
Lobe: 1. A subdivision of an organ, divided by fissures,
connective tissue or other natural boundaries. 2. A rounded
projecting portion, such as the lobe of the ear.
Lobectomy: An operation to remove an entire lobe of the lung.
Lobule: A little lobe.
Local therapy: Treatment that affects only a tumor and the area
close to it.
Local treatment: Treatment that affects the tumor and the area
close to it.
Lochia: The fluid that weeps from the vagina for a week or so
after delivery of a baby.
Lockjaw: See Tetanus.
Locomotion: Moving from one place to another.
Locus: The place, in Latin.. In genetics, a locus is the place a
gene occupies on a chromosome. One locus, two loci.
Locus minoris resistentiae: A place of less resistance, in
Latin. For example, a damaged heart valve may act as a locus
minoris resistentiae where bacteria released into the blood
stream (bacteremia) tend to settle.
Loin: The portion of the lower back from just below the ribs to
Longevity: Lifespan. (With increasing longevity, women will soon
be postmenopausal for one third of their lives).
Longitudinal: The word come from the Latin longitudo meaning
length. Hence, longitudinal means along the length, running
lengthwise, or (by extension) over the course of time.
Longitudinal section: A section that is cut along the long axis
of a structure. The opposite is a cross section.
Longitudinal study: A study done over the passage of time. For
example, a longitudinal study of children with Down syndrome (trisomy
21) might involve the study of 100 children with this condition
from birth to 10 years of age. Also called a diachronic study.
The opposite of a cross-sectional (synchronic) study.
Louse-borne typhus: A severe acute disease with prolonged high
fever up to 40° C (104° F), intractable headache, and a
pink-to-red raised rash. The cause is a microorganism called
Rickettsia prowazekii. It is found worldwide and is transmitted
by lice. The lice become infected on typhus patients and
transmit illness to other people. The mortality increases with
age and over half of untreated persons age 50 or more die. Also
called epidemic, European, classic typhus and jail fever.
Lower GI series: A series of x-rays of the colon and rectum that
is taken after the patient is given a barium enema. (Barium is a
white, chalky substance that outlines the colon and rectum on
Low-set ear: An ear positionned below its normal location.
Classified as a minor anomaly. Technically, the ear is low-set
when the helix (of the ear) meets the cranium at a level below
that of a horizontal plane through both inner canthi (the inside
corners of the eyes). The presence of 2 or more minor anomalies
in a child increases the probability that the child has a major
Lubricant: An oily or slippery substance. A vaginal lubricant
may be helpful for women who feel pain during intercourse
because of vaginal dryness.
Lues: An old name for syphilis, a sexually transmitted disease
(STD) that has been around for centuries and is caused by
Treponema pallidum, a microscopic organism called a spirochete,
a worm-like spiral-shaped organism that infects by burrowing
into the moist mucous membranes of the mouth or genitals. From
there, the spirochete produces the classic non-painful ulcer
known as a chancre. There are 3 stages of syphilis. The first
("primary") stage is formation of the chancre.. It is highly
contagious and can last 1-5 weeks. The disease can be
transmitted from any contact with one of the ulcers, which are
teeming with spirochetes. If the ulcer is outside the vagina or
on the scrotum, the use of condoms may not help
preventitransmission of the disease. Likewise, if the ulcer is
in the mouth, merely kissing can spread syphilis. Even without
treatment, an early infection resolves on its own in most women.
However, 25% will proceed to the next stage of the disease
called "secondary" syphilis, which lasts 4-6 weeks. This
secondary phase can include hair loss, a sore throat, white
patches in the nose, mouth, and vagina, fever, headaches, and a
skin rash. There can be lesions on the genitals that look like
genital warts but are caused by spirochetes rather than the wart
virus. These wart-like lesions, as well as the skin rash, are
highly contagious. The rash can occur on the palms of the hands
and the infection can be transmitted by casual contact. The
third stage of the disease involves the brain and heart and is
usually no longer contagious. At this point, however, the
infection can cause extensive damage to the internal organs,
such as the brain, and can lead to death.
Lumbar puncture: A lumbar puncture or "LP" is a procedure
whereby spinal fluid is removed from the spinal canal for the
purpose of diagnostic testing. It is particularly helpful in the
diagnosis of inflammatory diseases of the central nervous
system, especially infections, such as meningitis. It can also
provide clues to the diagnosis of stroke, spinal cord tumor and
cancer metastasis to the central nervous system.
Lumpectomy: A lumpectomy is a partial mastectomy, and
quadrentectomy refer to removing only a portion of the breast.
Lungs: The lungs are a pair of breathing organs located with the
chest which remove carbon dioxide from and bring oxygen to the
blood. There is a right and left lung.
Luteinizing hormone-releasing hormone: A hormone that controls
sex hormones in men and women. Also called LHRH.
Luxation: Complete dislocation of a joint. A partial dislocation
is a subluxation.
Lymph: The almost colorless fluid that travels through the
lymphatic system and carries cells that help fight infection and
Lymph nodes: Small, bean-shaped organs located throughout the
lymphatic system. The lymph nodes store special cells that can
trap cancer cells or bacteria that are traveling through the
body in lymph. Also called lymph glands.
Lymphadenopathy: Disease of the lymph nodes.
Lymphangiogram: X-rays of the lymphatic system. A dye is
injected to outline the lymphatic vessels and organs.
Lymphangioma: A structure consisting of a collection of blood
vessels and lymph vessels that are overgrown and clumped
together. Depending on their nature, these structures may grow
slowly or quickly. They can cause problems because of their
location. For example, a lymphangioma around the voicebox
(larynx) might cause a breathing problem.
Lymphatics: Lymphatics are small thin channels similar to blood
vessels. They do not carry blood, but collect and carry tissue
fluid from the body to ultimately drain back into the blood
Lymphatic system: The tissues and organs, including the bone
marrow, spleen, thymus, and lymph nodes, that produce and store
cells that fight infection and disease. The channels that carry
lymph are also part of this system.
Lymphedema: A condition in which excess fluid collects in tissue
and causes swelling. It may occur in the arm or leg after lymph
vessels or lymph nodes in the underarm or groin are removed.
Lymphocytes: White blood cells that fight infection and disease.
Lymphocytic: Referring to lymphocytes, a type of white blood
Lymphocytosis: Too many lymphocytes.
Lymphoid: Referring to lymphocytes, a type of white blood cell.
Also refers to tissue in which lymphocytes develop.
Lymphoid tissue: The part of the body's immune system that helps
protect it from bacteria.
Lymphoma: Tumor of the lymphoid tissue.
Lyon hypothesis: See Lyonizatioon.
Lyonization: The inactivation of an X chromosome. One of the two
X chromosomes in every cell in a female is randomly inactivated
early in embryonic development. Named after geneticist Mary
Lysis: Destruction. Hemolysis (hemo-lysis) is the destruction of
red blood cells with the release of hemoglobin.
Lytic: Suffix having to do with lysis. For example, hemolytic