Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «H»:
Hallucination, hypnagogic: See: Hypnagogic hallucination....
Hallucination, musical: See: Musical hallucination....
Hallucinogen: A drug that causes hallucinations (profound distortions 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. Hal...
Hallucinogenic: 1. As an adjective: Producing hallucinations. From hallucino- + -genic, a word ending meaning producing.
2. As a noun: A drug that induces hallucinations. (This is incorrect usage; the noun is hallucinogen.)...
Hallucinosis, musical: See: Musical hallucination....
Hallux: What the ancient Romans
called the big toe. Since hallux was a good enough word for the big toe among the ancient Romans, it has long done
yeoman's duty in medicine. Abnormalities of the big toe tend thus to be called hallux this-or-that.
For example, hallux valgus and hallux varus. In h...
Hallux valgus: A big toe (the
hallux) that is bent outward (valgus) so it overlaps the 2nd
toe. A bunion is a localized painful swelling at the base of the big
toe that can accompany hallux valgus. It is frequently associated
with inflammation. It can be related to inflammation of the nearby
Hallux varus: An inward bending
(varus) of the joint of the big toe (the hallux). ...
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. ...
Hamartoma, hypothalamic: A benign tumor of the hypothalamus, the area of the brain that controls body
temperature, hunger, and thirst. (In technical terms, the hypothalamus lies beneath a structure known as the thalamus and forms the floor of the third ventricle of the brain.)
A small hypothalamic ...
Hammer: The malleus....
Hammer toe: A flexed (curled) but not abnormally rotated toe. May require surgical correction....
Hamstring: The prominent tendons at
the back of the knee. They are the sidewalls of the hollow behind the knee. (This hollow is called the popliteal space). Both hamstrings connect to muscles that flex the knee. A pulled hamstring is a common athletic injury.
The "ham" of "hamstring" comes from
Hand, foot, and mouth disease
Hand, foot, and mouth disease: A common illness of infants and children under 10 years old characterized by fever, sores in the mouth, and a rash with blisters due to infection most commonly with coxsackievirus A16 or less often enterovirus 71 or another enterovirus.
The disease begins with a mild...
Hand-arm vibration syndrome
Hand-arm vibration syndrome: A disorder resulting from prolonged exposure to vibration, specifically to the hands and forearms while using vibrating tools. Symptoms include numbness, tingling, and loss of nerve sensitivity. The hand-arm vibration syndrome (HAVS) is a painful and potentially disablin...