Medical terms - Letter H | MedicalVocabulary.org

H

Symbol for hydrogen
H (drug caution code)

Abbreviation standing for habitforming on a medication that indicates caution because the medication may cause addictive. While not a part of the historical heritage of ancient prescription abbreviations, drug caution…
H and H

H and H, sometimes written as 'H&H', is a popular shorthand for hemoglobin and hematocrit, two very common and important blood tests. Hemoglobin is the oxygen-carrying protein pigment in the blood, specifically in…
H and P

In common doctor language, H stands for history and P for physical. So H and P = the history and physical, the medical history and the physical examination of the patient. The H and P are thus the initial clinical…
H. erectus

See: Homo erectus
H. floresiensis

See: Homo floresiensis
H. flu

Haemophilus influenzae type B
H. flu genome

The total genetic complement of the bacterium Haemophilus influenzae (H. flu). This bacterial genome was the first in an independent organism to be sequenced and assembled. The H. flu genome contains 1.8 million base…
H. flu immunization

This immunization is designed to prevent disease due to Haemophilus influenzae (H. flu), specifically Haemophilus influenzae type B (HIB). The HIB bacteria is responsible for a range of serious 'invasive' diseases…
H. heilmannii

Abbreviation for Helicobacter heilmannii, a bacteria that infects most cats, dogs and pigs and, in them, causes stomach inflammation (gastritis). H. heilmannii is not usually transmitted from animals to people. But…
H. sapiens

See: Homo sapiens
HAART

Stands for highly active antiretroviral therapy. Treatment with a very potent drug 'cocktail' to suppress the growth of HIV, the retrovirus responsible for AIDS
Habitual abortion

The miscarriage of 3 or more consecutive pregnancies. The abortion of 3 or more miscarriages (spontaneous abortions) with no intervening pregnancies is also termed recurrent abortion. Habitual or recurrent abortion is a…
Habitus

The physique or body build. Also the posture. For example, corticosteroid therapy can produce a characteristic cushingoid habitus with a moon face, 'buffalo hump' at the back of the neck, and obesity of the trunk. From…
Haemophilus influenzae genome

See: H. flu genome
Haemophilus influenzae type B

This kind of immunization is designed to prevent diseases caused by Haemophilus influenzae type B (HIB), a bacteria responsible for a range of serious "invasive" diseases including meningitis with potential brain damage…
Haemophilus influenzae type B (HIB) immunization

This kind of immunization is designed to prevent diseases caused by Haemophilus influenzae type B (HIB), a bacteria responsible for a range of serious 'invasive' diseases including meningitis with potential brain damage…
Hahnemann, Samuel

A sac from which a hair grows and into which the sebaceous (oil) glands open. The follicle is lined by cells derived from the epidermal (outside) layer of the skin. Each follicle normally goes through a five-year cycle…
Hair follicle

A sac from which a hair grows and into which the sebaceous (oil) glands open. The follicle is lined by cells derived from the epidermal (outside) layer of the skin. Each follicle normally goes through a five-year cycle…
Hair loss

Hair loss: Hair loss is the thinning of hair on the scalp. The medical term for hair loss is alopecia. Alopecia can be temporary or permanent. The most common form of hair loss occurs gradually and is referred to as…
Hair of the dog

An alcoholic chaser reputed to relieve a hangover, usually needed the morning after imbibing too much alcohol. There is no scientific evidence as to the efficacy of this time-honored treatment for a hangover. The saying…
Hair, exclamation point

Exclamation point hair is a key diagnostic finding in a disorder called alopecia areata. Alopecia areata is patchy baldness (alopecia means baldness and areata means occurring in patches) which typically begins with…
Hair, lanugal

The downy hair on the body of the fetus and newborn baby. The lanugal hair (or lanugo) is the first hair to be produced by the fetal hair follicles. It is very fine, soft and usually is unpigmented. The lanugal hair is…
Hair-on-end skull

Thin fine linear extensions radiating out from the skull that look on an X-ray like hair standing 'on-end' from the skull, an appearance associated with hemolytic anemias such as sickle cell disease and thalassemia. The…
Hairball

A wad of swallowed hair. Hairballs can sometimes be found to cause blockage of the digestive system, especially at the exit of the stomach. Interestingly, in the Far East culture, hairballs are felt to have medicinal…
Hairy cell leukemia

A form of chronic leukemia in which malignant B-lymphocytes (a type of white blood cell) are seen in the bone marrow, spleen, and peripheral blood and when viewed under the microscope, these cells appear to be covered…
Hairy-cell leukemia

See: Hairy cell leukemia
Hallervorden-Spatz disease

A genetic disorder in which there is progressive neurologic degeneration with the accumulation of iron in the brain. The gene for the disease is on chromosome 20 in region 20p13-p12.3. The syndrome was first described…
Hallucination

A profound distortion in a person's perception of reality, typically accompanied by a powerful sense of reality. An hallucination may be a sensory experience in which a person can see, hear, smell, taste, or feel…
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…
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 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…
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…
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…
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…
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…
Hand-foot-and-mouth disease

A viral syndrome with a rash on the hands and feet and in the mouth. The internal rash (the enanthem) consists of blisters and little ulcers that may involve not only the lining of the mouth but also the gums, palate…
Hand-foot-and-mouth syndrome

Hand-foot-and-mouth syndrome: A clinical pattern consisting of a rash on the hands and feet and in the mouth due to a viral infection. The internal rash (the enanthem) consists of blisters and little ulcers that may…
Handedness

The preferential use of one hand for most fine manual tasks. Right handedness is the preferential use of the right hand while left handedness is the preferential use of the left hand for most fine manual tasks. Being…
Hangman injury (Hangman's fracture)

A broken neck involving a fracture of an upper cervical vertebra similar to the injury suffered in death by hanging. The fracture always affects the vertebra called the axis -- the second cervical vertebra (C2) -- with…
Hangman's fracture

A broken neck involving a fracture of an upper cervical vertebra similar to the injury suffered in death by hanging. The fracture always affects the vertebra called the axis -- the second cervical vertebra (C2) -- with…
Hangover

A common nonmedical term for the disagreeable physical effects following excessive consumption of alcohol (or the use of other drugs). Veisalgia is the little-used medical name for the condition. It is also called a…