Webster's New World Medical Dictionary

hairy cell leukemia
See 
leukemia, hairy cell.
halitosis
An unpleasant odor from the mouth,
commonly referred to as bad breath. Halitosis can
be caused by the consumption of certain foods,
poor oral hygiene, alcohol or tobacco use, dry
mouth, or by certain chronic medical conditions.
hallucinogen
A drug or other chemical sub-
stance that causes hallucinations (profound distor-
tions in a person’s perceptions of reality). Under the
influence of hallucinogens, people see images, hear
sounds, and feel sensations that seem real but do
not exist. Some hallucinogens also produce rapid,
intense emotional swings. An example of a hallu-
cinogen is lysergic acid diethylamide (LSD).
hallux
The big toe.
hallux valgus
A condition in which the big toe
(hallux) is bent outward (toward the midline of the
foot; valgus) so that it overlaps the second toe.
Hallux valgus may be accompanied by a bunion
(localized painful swelling) and is frequently asso-
ciated with inflammation. It can be related to
inflammation of the nearby bursa (bursitis) or
degenerative joint disease (osteoarthritis).
hallux varus
A condition in which the joint of the
big toe is bent inward (away from the midline of the
foot; varus).
Halstead mastectomy
See 
mastectomy,
radical.
hamartoma
A benign (noncancerous) tumor-
like growth consisting of a disorganized mixture of
cells and tissues normally found in the area of the
body where the growth occurs.
hammer toe
A condition in which the toe is
flexed (curly), but with no abnormal rotation of the
toe. Hammer toe may require surgical correction.
hamstring
One of the prominent tendons at the
back of the knee. The hamstrings are the side walls
of the hollow behind the knee (popliteal space).
Both hamstrings connect to muscles that flex the
knee. The term is sometimes used to refer to the
muscles in the back of the thigh. A pulled hamstring
is a common athletic injury.