Copy of `Dorland's Medical Dictionary`

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Dorland's Medical Dictionary Category: Health and Medicine > Medical Dictionary Date & country: 31/12/2010, USA Words: 39128

LAVH
laparoscopically assisted vaginal hysterectomy.

law
(law) a uniform or constant fact or principle. law of independent assortment see Mendel's laws. law of segregation see Mendel's laws.

Lawrence-Seip syndrome
(law´rәns sīp´) total lipodystrophy.

lawrencium
(Lr) (law-ren´se-әm) a chemical element, atomic number 103, atomic weight 257.

laxative
(lak´sә-tiv) a medicine that loosens the intestinal contents and encourages defecation. One with a mild or gentle effect is also known as an aperient; one with a strong effect is referred to as a cathartic or purgative.

layer
(la´әr) a thin, flat plate or stratum of a composite structure; called also lamina.

layer of rods and cones
a layer of the retina, located between the pigmented part and the external limiting membrane, containing the sensory elements, the rods and cones.

layers of cerebral cortex
six anatomical divisions (I–VI) of the cerebral cortex (specifically the neocortex), distinguished according to the types of cells and fibers they contain.

lazy leukocyte syndrome
a syndrome occurring in children, marked by recurrent low-grade infections, associated with a defect in neutrophil chemotaxis and deficient random mobility of neutrophils.

lb
pound (L. libra).

LBW
low birth weight; see low birth weight infant.

LCL bodies
minute coccoid bodies found in tissue infected with psittacosis.

LCM virus
lymphocytic choriomeningitis virus.

LD
lethal dose.

LD50
median lethal dose.

LDH
lactate dehydrogenase.

LDL
low-density lipoprotein.

LDL receptors
low-density lipoprotein receptors specific receptors for low-density lipoproteins found in coated pits on the surface of mammalian cells. The coated pits are internalized forming coated vesicles from which the receptors are recycled back to the plasma membrane while particles of low-density lipoprotein are transferred to lysosom...

LDL-C
low-density-lipoprotein cholesterol; see cholesterol.

LDR
labor, delivery, recovery; see labor, delivery, recovery room.

LDR room
labor, delivery, recovery room.

LDRP
labor, delivery, recovery, postpartum; see labor, delivery, recovery, postpartum room.

LDRP room
labor, delivery, recovery, postpartum room.

LE
lupus erythematosus.

LE body
hematoxylin body.

LE cell
a neutrophil or macrophage that has ingested the nuclear material of an injured cell, converted to a dense, homogeneous mass by reaction with antinuclear antibodies; this mass of nuclear material is called a hematoxylin body. This is a characteristic of systemic lupus erythematosus, but also found in analogous connective tissue disor...

Le Dentu suture
a type used for a divided tendon; two stitches are passed on each side, right and left, and are tied in front, and a third is taken from right to left above and below the cut and is tied on one side.

LE factor
an immunoglobulin that reacts with leukocyte nuclei, found in the serum in systemic lupus erythematosus.

Le Fort fracture
bilateral horizontal fracture of the maxilla, classified as Le Fort I, Le Fort II, or Le Fort III according to degree of severity, with Le Fort III fractures being the most serious, usually involving multiple fractures of facial bones. Le Fort I fracture a horizontal segmented fracture of t...

Le Fort operation
(lә for´) uniting the anterior and posterior vaginal walls at the middle line to repair or prevent uterine prolapse.

Le Fort osteotomy
transverse sectioning and repositioning of the maxilla; the incision for each of the three types (Le Fort I, II, and III o's) is placed along the line defined by the corresponding Le Fort's fracture. Le Fort III osteotomy.

Le Fort suture
for a divided tendon: a single loop is passed above the cut, entering at one side, coming out and going in at the front; it is then passed below the cut at each side, coming out in front, and is there tied.

LE phenomenon
the formation of LE cells on incubation of normal neutrophils with the serum of patients with systemic lupus erythematosus; see also LE test.

LE test
a formerly common test for systemic lupus erythematosus: serum from patients with lupus is combined with normal leukocytes; following incubation at 37° C., polymorphonuclear leukocytes engulf nuclei or nuclear fragments of cells to form LE cells.

lead
(Pb) (lēd) a chemical element, atomic number 82, atomic weight 207.19. Excessive ingestion or absorption causes lead poisoning.

lead
(lēd) a pair of electrodes attached to a wire, used in recording changes in electric potential, created by activity of an organ, such as the heart (electrocardiography) or brain (electroencephalography).

lead axis
the imaginary direct line between the two electrodes of the bipolar leads or between the positive electrode and the reference point of the unipolar leads.

lead encephalitis
encephalitis with cerebral edema due to lead poisoning.

lead encephalopathy
brain disease caused by lead poisoning.

lead I
the standard bipolar limb lead attached to the right and left arms.

lead II
the standard bipolar limb lead attached to the right arm and left leg.

lead III
the standard bipolar limb lead attached to the left arm and left leg.

lead line
a purple-blue line at the edge of the gums in chronic lead poisoning; called also blue line.

lead nephropathy
the kidney damage that accompanies lead poisoning; lead deposits appear in the epithelium of the proximal tubules and as nuclear inclusions in cells. In time this leads to tubulointerstitial nephritis with chronic renal failure and other symptoms.

lead paralysis
paralysis caused by lead poisoning, with wristdrop due to a peripheral neuritis.

lead pipe fracture
one in which the bone cortex is slightly compressed and bulged on one side with a slight crack on the other side of the bone.

lead poisoning
poisoning caused by lead or lead salts in the body; it affects the brain, nervous system, blood, and digestive system and can be either chronic or acute. Chronic lead poisoning was once fairly common among painters, but it became less frequent when lead-free paints were substituted for lead-based ones. It is still seen am...

leakage
(le´kaj) the escape of something through a break in a barrier or wall. radiation leakage radiation going out through the x-ray tube housing in all directions other than that of the useful beam.

leakage current
the electrical current that exists in the parts or metal case of electrical equipment.

leaping atrophy
a type of progressive muscular atrophy that begins in the hand and extending to the shoulder without affecting the muscles of the arm.

learning disorders
a group of disorders characterized by academic functioning that is substantially below the level expected on the basis of the patient's chronological age, measured intelligence, and age-appropriate education.

least splanchnic nerve
origin, last ganglion of sympathetic trunk or lesser splanchnic nerve; distribution, aorticorenal ganglion and adjacent plexus; modality, sympathetic and visceral afferent.

Leber disease
(la´ber) Leber hereditary optic neuropathy. Leber congenital amaurosis.

Leber hereditary optic neuropathy
(la´ber) Leber optic atrophyLeber optic neuropathy a maternally transmitted disorder characterized by bilateral progressive optic atrophy, with onset usually at about the age of twenty. Degeneration of the optic nerve and papillomacular bundle results in progressive loss of central vision that may remit spontaneous...

lecithin
(les´ĭ-thin) phosphatidylcholine.

lecithin-sphingomyelin ratio
(L-S ratio) the ratio of lecithin to sphingomyelin in amniotic fluid, the determination of which is helpful in establishing the maturity of the fetus and its susceptibility to hyaline membrane disease after birth.

lectin
(lek´tin) a term applied to hemagglutinating substances present in saline extracts of certain plant seeds, which specifically agglutinate erythrocytes of certain blood groups or stimulate lymphocyte proliferation.

Lee test
(for rennin) add 5 drops of gastric juice to 5 mL of milk; coagulation should take place in 20 minutes in the incubator.

leech
(lēch) any of the annelids of the class Hirudinea, especially Hirudo medicinalis; some species are bloodsuckers. Leeches were used extensively to treat various disorders and are still used occasionally to reduce postsurgical venous congestion, as in tissue flaps, grafts, or transplants.

Leede-Rumpel phenomenon
Rumpel-Leede phenomenon.

leflunomide
(lә-floo´no-mīd) an immunomodulator used as a disease-modifying antirheumatic drug in treatment of rheumatoid arthritis, administered orally.

left anterior fascicular block
left anterior hemiblock; see hemiblock. See also fascicular block.

left atrial veins of heart
a group of smallest cardiac veins that are sometimes present and that empty into the left atrium of the heart.

left atrioventricular orifice
mitral orifice.

left bundle branch block
(LBBB) see bundle branch block.

left colic artery
origin, inferior mesenteric artery; branches, none; distribution, descending colon.

left colic flexure
the angular junction of the transverse and descending colon.

left colic vein
a vein that follows the left colic artery and opens into the inferior mesenteric vein.

left coronary artery
origin, left aortic sinus; branches, anterior interventricular and circumflex branches; distribution, left ventricle, left atrium.

left coronary catheter
one designed for coronary arteriography of the left coronary artery.

left coronary vein
the portion of the great cardiac vein lying in the coronary sulcus; it receives blood from the anterior interventricular vein and empties into the coronary sinus.

left gastric artery
origin, celiac trunk; branches, esophageal branches; distribution, esophagus, lesser curvature of stomach.

left gastric vein
the accompanying vein of the left gastric artery, emptying into the portal vein.

left gastro-omental artery
origin, splenic artery; branches, gastric, omental branches; distribution, stomach, greater omentum.

left gastro-omental vein
a vein that follows the distribution of the left gastro-omental artery and empties into the splenic vein.

left gastroepiploic artery
left gastro-omental artery.

left gastroepiploic vein
left gastro-omental vein.

left heart bypass
diversion of the flow of blood from the pulmonary veins directly to the aorta, avoiding the left atrium and the left ventricle.

left hepatic vein
the large hepatic vein that drains the central veins in the left side of the liver and empties into the inferior vena cava.

left inferior pulmonary vein
a vein that returns blood from the lower lobe of the left lung (from the superior segmental and common basal veins) to the left atrium of the heart.

left lobe of liver
traditional name for the smaller of the two main portions of the liver, separated from the right lobe by the falciform ligament. It is bordered in the rear by the caudate and quadrate lobes.

left lymphatic duct
thoracic duct.

left marginal artery
a branch of the circumflex branch of the left coronary artery, which follows the left margin of the heart and supplies the left ventricle.

left marginal vein
a vein ascending along the left margin of the heart, draining the left ventricle and emptying into the great cardiac vein.

left ovarian vein
a vein that drains the left pampiniform plexus of the broad ligament and empties into the left renal vein.

left posterior fascicular block
left posterior hemiblock; see hemiblock. See also fascicular block.

left pulmonary artery
origin, pulmonary trunk; branches, numerous, named according to the segments of the lung to which they distribute unaerated blood; distribution, left lung.

left superior intercostal vein
the common trunk formed by union of the second, third, and sometimes fourth posterior intercostal veins, which crosses the arch of the aorta and joins the left brachiocephalic vein.

left superior pulmonary vein
the vein that returns blood from the upper lobe of the left lung (from the apicoposterior, anterior segmental, and lingular veins) to the left atrium of the heart.

left suprarenal vein
a vein that returns blood from the left suprarenal gland to the left renal vein.

left testicular vein
a vein that drains the left pampiniform plexus and empties into the left renal vein.

left ventricle of heart
the lower chamber of the left side of the heart, which pumps oxygenated blood out through the aorta to all the tissues of the body.

left ventricular failure
left ventricular heart failure left-sided heart failure.

left ventricular stroke work index
(LVSWI) an index of the amount of work (stroke work) performed by the left ventricle of the heart.

left-sided heart failure
left ventricular heart failure failure of the left ventricle to maintain a normal output of blood; it does not empty completely and thus cannot accept all the blood returning from the lungs via the pulmonary veins, which become engorged. Fluid seeps out of the veins through the pulmonary capillaries and collects in the interstit...

left-to-right shunt
diversion of blood from the left side of the heart to the right side, or from the systemic to the pulmonary circulation through an anomalous opening such as a septal defect or patent ductus arteriosus.

leg
(leg) that section of the lower limb between the knee and ankle; called also crus. in common usage, the entire lower limb (in which case, the part below the knee is called the lower leg). any of the four limbs of a quadruped. bayonet leg ankylosis of the knee a...

leg sign
Schlesinger sign. Neri sign.

legal blindness
that defined by law; in the United States it is usually defined as vision in the better eye after correction of 20/200 or worse, or total diameter of the visual field in the better eye of 20° or less.

legal medicine
forensic medicine.