Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «L»:
Ligament, patellar: See: Patellar tendon....
Ligament, posterior cruciate
Ligament, posterior cruciate: 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 stability and strength to the knee joint.
Ligaments, knee: Ligaments are strong, elastic bands of tissue that connect bone to bone. They provide strength and stability to the joint.
Four ligaments connect the femur (the bone in the thigh) with the tibia (the larger bone in the lower leg):
The medial collateral ligament (MCL) provides stab...
Ligand: A molecule that binds to another. Often, a soluble molecule such as a hormone or neurotransmitter that binds to a receptor.
From the Latin ligandus, binding from the root ligare, to bind or tie. Ligate and ligature come from the same root....
Ligate: To tie or to tie off, as in to ligate an artery.
From the Latin "ligare" meaning "to bind or tie." Ligature and ligand come from the same root....
Ligature: In surgery, a filament or thread used to tie something, such a blood vessel to prevent it from bleeding or the pedicle of a tumor to constrict it. Ligatures may be of silk, gut, wire, and other materials.
From the Latin "ligare" meaning to "bind or tie." Ligate and ligand come from the sa...
Lightening: Not to be
confused with a discharge of atmospheric electricity, lightening refers to the
sensation that a pregnant woman feels when the baby drops. This is the time when the presenting (lowermost) part of the fetus descends into the
Lightening classically occurs 2 to ...
Lightheadedness: A feeling you are
"going to faint." Lightheadedness is medically distinct
from dizziness, unsteadiness, and vertigo. See:
Dizziness, Unsteadiness, and Vertigo....
Lightning injuries: A major source of injury and death from the environment, lightning is one of the top 3 causes of death from environmental origins. (The other top environmental killers are floods and extreme temperatures.)
Lightning is neither a direct current nor an alternating current. It is a ...
Lights, flashing: A sensation of flashing lights
is created when the vitreous (the clear, jelly-like
substance that fills the middle of the eye) shrinks
and tugs on the retina. These flashes of light can appear
off and on for several weeks or months. With age, it is
more common to experience fl...
Lilliputian hallucination: An hallucination in which things, people, or animals seem smaller than they would be in real life. Lilliputian refers to the "little people" who lived (fictionally) on the island of Lilliput in Jonathan Swift's 1726 masterpiece Gulliver's Travels.
The term "Lilliputian hal...
Limb: The arm or leg. ...
Limb-girdle muscular dystrophy
Limb-girdle muscular dystrophy: See: Muscular dystrophy, limb-girdle....
Liminal: In neurolgy, at the threshold of perception to a sensory stimulus. In other words, just barely perceptible to the senses.
"Liminal" comes from the Latin noun "limen" meaning
"threshold." It makes sense, then, that "liminal" applies to
the idea of a sensory threshold. "Subliminal" is below ...
Lindane: An organochlorine pesticide and nerve poison. Also a suspected carcinogen (cancer-causing agent). Although many countries have banned lindane, it is still used in the US for treating head lice and scabies. Also known as gamma-hexachlorocyclohexane (HCH).
The US Food and Drug Administration ...