Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «L»:
Loeys-Dietz syndrome is an inherited syndrome characterized by aortic aneurysms (weakened outpouchings of the aorta) and other blood
vessel abnormalities in children. Other physical characteristics may be
associated with Loeys-Dietz syndrome, including early fusion of the sk...
Loiasis: The disease caused by the eye worm known as loa loa, a parasite that lives in humans and other primates. People contract the parasite when bitten by infected deer flies. The larvae of the worm enter the bloodstream and later develop into adult worms. Symptoms may not appear for months or ye...
Loin: The portion of the lower back from just below
the rib cage to the pelvis. The loins include the psoas muscles which
are very powerful muscles in the lower back.
The term "loin" is more often encountered now at the meat counter
than in medicine. It is also commonly encountered in the Bible...
Loneliness, fear of
Loneliness, fear of: An abnormal and persistent fear of loneliness, of being alone. Sufferers of this fear experience undue anxiety even though they realize that being alone does not threaten their well-being. They may worry about being ignored and unloved, or they may worry about intruders, strange...
Long arm of a chromosome
Long arm of a chromosome: The long arm of a
chromosome is termed the q arm. All human chromosomes have
2 arms, the p (short) arm and the q (long) arm.
They are separated from each other only by a primary
constriction, the centromere, the point at which the
chromosome is attached to the spind...
Long QT syndrome
Long QT syndrome: An inherited defect in heart rhythm that predisposes to syncope without warning (sudden fainting spells), dizziness, palpitations, seizures and sudden death. The name of the syndrome comes from the QT segment in the tracing on the electrocardiogram (ECG). This segment lasts slightl...
Long-chain-3-hydroxyacyl-CoA dehydrogenase def
Long-chain-3-hydroxyacyl-CoA dehydrogenase 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
The mother (and...
Long-term care facility
Long-term care facility: A facility that provides rehabilitative, restorative, and/or ongoing skilled nursing care to patients or residents in need of assistance with activities of daily living. Long-term care facilities include nursing homes, rehabilitation facilities, inpatient behavioral health f...
Long-term memory: A system for permanently
storing, managing, and retrieving information for later
use. Items of information stored as long-term memory may be
available for a lifetime.
Long-term memory is in contrast to short-term memory....
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 (synch...
Lordosis: Inward curvature of the spine. Normally,
for example, the low back demonstrates lordosis. The spine is not
supposed to be absolutely straight, so some degree of curvature is
normal. When the curve exceeds the usual range, it may be due to
musculoskeletal disease or simple poor posture....
Loss-of-function mutation: A mutation that results in reduced or abolished protein function. Gain-of-function mutations,which are much less common, confer an abnormal activity on a protein....