Webster's New World Medical Dictionary

angiotensin converting enzyme
See 
ACE.
angle-closure glaucoma
Increased pressure in
the front chamber of the eye due to blockage of its
normal circulation of fluid. When the iris retracts
and thickens (when the pupil of the eye is wide
open), it blocks the drainage pathway for fluid in
the eye. This causes the pressure in the eye to soar,
which can damage the optic nerve and lead to blind-
ness. The elevated pressure is ideally to be detected
before the appearance of other symptoms of angle-
closure glaucoma, so the pressure is routinely
checked during eye exams. Symptoms of acute
angle-closure glaucoma include severe eye and
facial pain, nausea and vomiting, blurred vision,
and a halo effect around lights. Acute angle-closure
glaucoma is an emergency because optic nerve
damage and vision loss can occur within hours of its
onset. Angle-closure glaucoma tends to affect peo-
ple born with a narrow angle between the cornea
and iris. See also 
glaucoma.
anhidrosis
Lack of sweating. Anhidrosis creates
a dangerous inability to tolerate heat.
anisocoria
A condition in which the left and right
pupils of the eyes are not of equal size. The size of
the pupil determines how much light is let into the
eye. With anisocoria, the larger pupil lets more light
enter the eye. There are many causes of anisocoria,
including eye injury or infection and swelling within
the brain.
anisocytosis
Excessive inequality in the size of
the red blood cells. Anisocytosis is apparent on a
blood smear examined under a microscope.
ankle
A complex structure made up of two joints:
the true ankle joint and the subtalar joint. The
ankle’s movement is constrained and controlled by
ligaments, including the anterior tibiofibular liga-
ment, which connects the tibia to the fibula; the lat-
eral collateral ligaments, which attach the fibula to
the calcaneus to give the outside of the ankle stabil-
ity; and the deltoid ligaments on the inside of the
ankle, which connect the tibia to the talus and cal-
caneus to provide medial stability to the ankle. See
also 
ankle joint.
ankle joint
A joint that is composed of three
bones: the tibia, the fibula, and the talus. The ankle
joint is responsible for the up-and-down motion of
the foot. The subtalar joint is under the ankle joint,
and it consists of the talus on top and calcaneus on
the bottom. The subtalar joint is responsible for the
side-to-side motion of the foot.