Webster's New World Medical Dictionary

learning disability
One of several childhood
disorders characterized by difficulty with certain
skills such as reading or writing in individuals with
normal intelligence. Learning disorders affect the
ability to interpret what one sees and hears or
the ability to link information from different parts of
the brain. These limitations can show up in many
ways—as specific difficulties with spoken and writ-
ten language, coordination, self-control, or atten-
tion. Such difficulties extend to schoolwork and can
impede learning to read or write, or to do math. In
some people, many overlapping learning disabilities
may be apparent. Other people may have a single,
isolated learning problem that has little impact on
other areas of their lives. A learning disability is
often called a learning problem.
left heart
See 
heart, left.
left heart hypoplasia syndrome
See 
hypoplas-
tic left heart syndrome.
left ventricle
See 
ventricle, left.
leg
In popular usage, the part of the body from
the top of the thigh down to the foot, and in medical
terminology, the portion of the lower extremity that
runs from the knee to the ankle. The leg (in the
medical sense) has two bones—the tibia (shin-
bone) and the fibula—both of which are known as
long bones. The larger of the two is the tibia. The
fibula runs alongside the tibia.
leg, ankle, and foot bones
See 
bones of the
leg, ankle, and foot.
leg, restless
See 
restless leg syndrome.
leg, upper
More properly called the thigh, the
upper leg is the area between the knee and the hip.
It has only one bone, the femur, which spans the
distance from the hip to the knee.