Medical terms - Letter L (page 4) | MedicalVocabulary.org

LCHAD deficiency

Acute fatty liver of pregnancy (AFLP) has been found to be associated in some cases with an abnormality of fatty-acid metabolism. This abnormality is a deficiency of the enzyme long-chain-3-hydroxyacyl-CoA…
LCL (lateral collateral ligament) of the knee

The knee joint is surrounded by a joint capsule with ligaments strapping the inside and outside of the joint (collateral ligaments) as well as crossing within the joint (cruciate ligaments). These ligaments provide…
LCSW

Licensed clinical social worker
LDH

Lactate dehydrogenase
LDL (low-density lipoprotein)

A molecule that is a combination of lipid (fat) and protein. Lipoproteins are the form in which lipids are transported in the blood. Low-density lipoprotein (LDL) transports cholesterol from the liver to the tissues of…
LDL cholesterol

Lipoproteins which are combinations of lipids (fats) and proteins are the form in which lipids are transported in the blood. The low-density lipoproteins transport cholesterol from the liver to the tissues of the body…
Lead poisoning

Lead poisoning: An environmental hazard capable of causing brain damage. In the US lead poisoning is formally defined as having at least 10 micrograms of lead per deciliter of blood. (The average level of lead, for…
Lead-based paint

Paint or other surface coatings that, by definition, contain lead in excess of 1.0 milligrams per square centimeter (mg/cm2) 0.5 percent by weight.
Leaded

1. Framed, covered, or weighted with lead. As a leaded window. 2. Added in the form of tetraethyl lead as an anti-knock agent to gasoline (petrol). See: Lead poisoning
Leaded gasoline

See: Tetraethyl lead
Leaded petrol

See: Tetraethyl lead
Lean body mass

The mass of the body minus the fat (storage lipid). There are a number of methods for determining the lean body mass. Some of these methods require specialized equipment such as underwater weighing (hydrostatic…
Learning disability

Learning disability: A childhood disorder characterized by difficulty with certain skills such as reading or writing in individuals with normal intelligence. Learning disorders affect the ability to interpret what one…
Learning problem

See: Learning disability
Lecithinase

See: Phospholipase
Lectin

A complex molecule that contains both protein and sugar. Lectins are made by both animals and plants and are able to bind to the outside of a cell and cause biochemical changes in it
Lederberg

See: Lederberg, Joshua
Lederberg, Joshua

(1925- ) American geneticist and microbiologist who received the Nobel prize in 1958 for his work in bacterial genetics. He shared the prize with George W. Beadle and Edward L. Tatum, who won 'for their discovery that…
Leech

1. An aquatic parasite that sucks blood from animals. Leeches play a role in medicine today. See: Leech therapy. 2. (Archaic) A physician or surgeon (because they did so much leeching). 3. A person who behaves as a…
Leech therapy

The use of leeches in medical treatment. Once used as an almost universal cure, leeches were largely abandoned by medicine but in the second half of the 20th century refound a role. That role is largely in plastic and…
Left atrium

The upper right chamber of the heart. The left atrium receives oxygenated blood from the lungs and pumps it down into the left ventricle which delivers it to the body. NTER>
Left heart

The heart is composed functionally of two hearts - the right heart and the left heart. The left heart consists of the left atrium which receives oxygenated blood from the lung and the left ventricle which pumps it out…
Left heart hypoplasia syndrome

A form of congenital heart disease in which the whole left half of the heart (including the aorta, aortic valve, left ventricle and mitral valve) is underdeveloped (hypoplastic). Blood returning from the lungs has to…
Left hepatic duct

The duct that drains bile from the left half of the liver and joins the right hepatic duct to form the common hepatic duct. NTER>
Left ventricle

The left lower chamber of the heart that receives blood from the left atrium and pumps it out under high pressure through the aorta to the body
Left ventricular assist device

See: Ventricular assist device
Left-handed

In popular usage, the leg extends from the top of the thigh down to the foot. However, in medical terminology, the leg refers to the portion of the lower extremity from the knee to the ankle. The leg has two bones: the…
Leg

In popular usage, the leg extends from the top of the thigh down to the foot. However, in medical terminology, the leg refers to the portion of the lower extremity from the knee to the ankle. The leg has two bones: the…
Leg pain with cramping

An aching, crampy, tired, and sometimes burning pain in the legs that comes and goes -- it typically occurs with walking and goes away with rest -- due to poor circulation of blood in the arteries of the legs. Known…
Leg, ankle and foot bones

There are 62 lower extremity bones. They consist of 10 hip and leg, 14 ankle and 38 foot bones. > >The 10 hip and leg bones are the innominate or hip bone (fusion of the ilium, ischium, and pubis), femur, tibia, fibula…
Leg, lower

The lower leg is the bottom segment of the leg: the part below the knee. The lower leg contains two long bones. The larger of these two bones is the tibia, the smaller one the fibula. The tibia is familiarly known as…
Leg, upper

The upper leg is the superior (top) segment of the leg: the part above the knee. As compared to the lower leg which boasts two bones (the tibia and the fibula), the upper leg has only one bone: the femur but a very…
Legal blindness

The criteria used to determine eligibility for government disability benefits and which do not necessarily indicate a person's ability to function. In the US, the criteria for legal blindness are: > >Visual acuity of…
Legal medicine

The branch of medicine that deals with the application of medical knowledge to legal problems and legal proceedings. Legal medicine is also called forensic medicine. A physician may be engaged in legal (or forensic)…
Legg disease

See Legg-Calve-Perthes disease
Legg-Calve-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), causing it to deteriorate. The disease is most common at age 6 to 9, tends to…
Legg-Perthes disease

See Legg-Calve-Perthes disease
Legionella

The bacterium that causes Legionnaires' disease. This disease is due specifically to the bacterium Legionella pneumophila found in plumbing, shower heads and water-storage tanks. Outbreaks of Legionella pneumonia have…
Legionnaire disease

A disease due to the bacteria Legionella pneumophila found in plumbing, shower heads and water-storage tanks. Outbreaks of Legionella pneumonia have been attributed to evaporative condensers and cooling towers. The…
Leiomyoma

A benign tumor of smooth muscle, the type of muscle that is found in the heart and uterus. A leiomyoma of the uterus is commonly called a fibroid. Uterine fibroids are the single most common indication for hysterectomy…
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…
Leishmania

A group of parasites causing a disease called leishmaniasis. For a fuller definition and more information, see Leishmania infection
Leishmania infection

A parasitic disease, also called leishmaniasis, spread by the bite of sand flies infected with a protozoa (Leishmania). There are several forms of leishmaniasis, the most common being cutaneous and visceral…
Leishmaniasis

Leishmaniasis: Diseases due to the parasite called Leishmania involving the organs (kala-azar) or the skin plus mucous membranes (espundia), or the skin alone (usually named for the place plus boil, button or sore as…
Leishmaniasis, visceral

See: Visceral leishmaniasis
Lemierre syndrome

A potentially lethal form of sore throat caused by the bacterium Fusobacterium necrophorum, a common inhabitant of the mouth. This disease vanished with the advent of antibiotics but then returned decades later. It has…
Lenin

(1870-1924) Vladimir Ilyich Lenin, the founder of the Bolshevik Party and the Soviet state. Lenin is of some medical interest because he has been retrospectively diagnosed with syphilis. Lenin may have contracted the…
Lennox syndrome

A severe form of epilepsy that is characterized by the onset in early childhood of frequent seizures of multiple types, developmental delay, a particular brain wave pattern (a slow spike-and-wave pattern), and…
Lennox-Gastaut syndrome

A severe form of epilepsy that is characterized by the onset in early childhood of frequent seizures of multiple types, developmental delay, a particular brain wave pattern (a slow spike-and-wave pattern), and…
Lens

The transparent structure inside the eye that focuses light rays onto the retina (the nerve layer that lines the back of the eye, senses light and creates impulses that go through the optic nerve to the brain). The lens…