Webster's New World Medical Dictionary

ligament
A tough band of connective tissue that
connects various structures, such as two bones.
ligament, anterior cruciate
See 
anterior cru-
ciate ligament.
ligament, lateral collateral knee
See 
lateral
collateral ligament of the knee.
ligament, medial collateral knee
See 
medial
collateral ligament of the knee.
ligament, posterior cruciate
See 
posterior
cruciate ligament.
ligaments, knee
The four strong, elastic bands
of tissue that connect bone to bone in the knee.
They provide strength and stability to the joint.
These 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),
which provides stability to the inner (medial) aspect
of the knee; the lateral collateral ligament (LCL),
which provides stability to the outer (lateral) aspect
of the knee; the anterior cruciate ligament (ACL), in
the center of the knee, which limits rotation and the
forward movement of the tibia; the posterior cruci-
ate ligament (PCL), in the center of the knee, which
limits backward movement of the tibia. Other liga-
ments are part of the knee capsule, which is a pro-
tective, fiber-like structure that wraps around the
knee joint.
ligand
A molecule that binds to another. Often, a
soluble molecule such as a hormone or neuro-
transmitter that binds to a receptor.
ligate
To tie, as in to ligate (tie off) an artery.
ligature
Material used to tie something in surgery.
Ligatures are used to tie off blood vessels, and they
may be made of silk, gut, wire, or other materials.
lightening
See 
engagement.
lightheadedness
A feeling that one is about to
faint. Lightheadedness is medically distinct from
dizziness, unsteadiness, and vertigo. See also 
dizzi-
ness; unsteadiness; vertigo.