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L, l

Lactobacillus; Latin; left; left eye; length; lethal; light sense; liter.


In biochemistry, a symbol used as a prefix to indicate that the carbon atom is symmetrical (or achiral) and that only three dissimilar groups attach to it. SEE: D-.

L1, L2, etc.

first lumbar nerve, second lumbar nerve, and so forth.


left atrium.


Symbol for the element lanthanum.


left atrial appendages


(lab) Colloquial for laboratory.


long-acting beta agonist.


(lā′bĕl) [Fr. label, strip of cloth, ribbon] The attachment of a radioactive marker or other chemical to a biologically active substance such as a drug or body chemical (such as glucose, protein, or fat). The metabolic fate of the labeled material may be investigated by detecting the presence of the label in various body sites or in excretions. The labeling material is chosen so that it does not alter the metabolism or action of the substance being investigated. 2. In computer informatics, an output. 3. An assigned diagnosis. SEE: tracer.

labeled use

(lā′bĕld) Indication (2).


SEE: radioactive tag; tagging.

la belle indifference, la belle indifférence

(la bel en-di-fā-rons′) [Fr. la belle indifférence, beautiful indifference] A disproportionate degree of indifference to, or complacency about, symptoms such as paralysis or loss of sensation in a part of the body. It is characteristic of conversion disorders.


(lā′bē-ă) [L. labia, lips] Pl. of labium. SEE: labium.

l. majora The two folds of skin and adipose tissue on either side of the labia minora and vaginal opening that form the lateral borders of the vulva. Their medial surfaces unite anteriorly above the clitoris to form the anterior commissure; posteriorly they are connected by a poorly defined posterior commissure. They are separated by a cleft (rima pudendi) into which the urethra and vagina open. In young girls, their medial surfaces are in contact with each other, concealing the labia minora and vestibule. In older women, the labia minora may protrude between them.

l. minora The two thin folds of integument that lie between the labia majora and enclose the vestibule. Anteriorly each divides into two smaller folds that unite with similar folds from the other side and enclose the clitoris, the more anterior one forming the prepuce of the clitoris (preputium clitoridis) and the posterior one the frenulum clitoridis. In young girls, they are ...

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