Copy of `Dorland's Medical Dictionary`

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Dorland's Medical Dictionary Category: Health and Medicine > Medical Dictionary Date & country: 31/12/2010, USA Words: 39128

gyri transitivi
(ji´ri tran″sĭti´vi) annectent gyri.

gyrospasm
(ji´ro-spaz″әm) rotatory spasm of the head.

gyrus
(ji´rәs) pl. gy´ri one of the many convolutions of the surface of the cerebral hemispheres caused by infolding of the cortex, separated by fissures or sulci; called also cerebral gyrus.

gyrus cinguli
cingulate gyrus.

gyrus hippocampi
(ji´rәs hip″o-kam´pi) hippocampal gyrus

gyrus rectus
(ji´rәs rek´tәs) a cerebral convolution on the orbital aspect of the frontal lobe.

HA
hepatitis A.

Haab reflex
bilateral pupillary contraction when the patient sits in a darkened room, and without accommodation or convergence directs attention to a bright object already within the field of vision. Called also cerebral cortex reflex.

Haagensen test
observation of the contour of the breasts when the patient leans forward as a means of detecting malignant changes.

HAART
highly active antiretroviral therapy.

habena
(hә-be´nә) pl. habe´nae Latin word meaning strap. In anatomy, it is used to name a straplike structure.

habenula
(hә-ben´u-lә) pl. haben´ulae any frenulum, especially one of a series of structures in the cochlea. a raised triangular area of the dorsomedial surface of the thalamus anterior to the pineal gland. It is a part of the epithalamus. adj., haben´ular., adj.

Habermann disease
(hah´ber-mahn) pityriasis lichenoides et varioliformis acuta.

habilitation
(hah-bil″ĭ-ta´shәn) the assisting of a child with achieving developmental skills when impairments have caused delaying or blocking of initial acquisition of the skills. Habilitation can include cognitive, social, fine motor, gross motor, or other skills that contribute to mobility, communication, ...

habit
(hab´it) an action that has become automatic or characteristic by repetition. predisposition; bodily temperament.

habit scoliosis
scoliosis due to improper posture.

habit spasm
habit tic.

habitual abortion
spontaneous abortion in three or more consecutive pregnancies before the 20th week of gestation.

habituation
(hә-bich″u-a´shәn) the gradual adaptation to a stimulus or to the environment. the extinction of a conditioned reflex by repetition of the conditioned stimulus. older term denoting sometimes tolerance and other times a psychological dependence resulting from the repeated consumpti...

habitus
(hab´ĭ-tәs) posture or position of the body. physique; body build and constitution. See also body type.

Hadfield-Clarke syndrome
(had´fēld klahrk´) Clarke-Hadfield syndrome.

Haemaphysalis
(he″mә-fis´ә-lis) a genus of hard ticks, species of which are important vectors of diseases such as Q fever and tularemia.

Haemophilus
(he-mof´ĭ-lәs) a genus of hemophilic gram-negative bacteria. H. aphro´philus, H. parainfluen´zae, and H. paraphro´philus are part of the normal oral flora and are occasionally associated with endocarditis. Pathogenic species include H. aegyp´tius, the cause of pinkeye (acute contagious conjunctivitis); H. ducrey´i,...

Haemophilus
b conjugate vaccine(HbCV) a preparation of Haemophilus influenzae type b capsular polysaccharide covalently bound to diphtheria toxoid or to a specific other protein; it stimulates both B and T lymphocyte responses and is much more immunogenic than the polysaccharide vaccine. Administered intramuscularly as a rout...

Haemophilus
b polysaccharide vaccine(HbPV) a preparation of highly purified capsular polysaccharide derived from Haemophilus influenzae type b, which stimulates an immune response in B lymphocytes only; administered intramuscularly or subcutaneously as an immunizing agent in children ages 18 months to 5 years.

Haemophilus influenzae
pneumonia bacterial pneumonia caused by infection with Haemophilus influenzae, seen mainly in young children and debilitated or immunocompromised adults; it sometimes progresses to life-threatening conditions such as meningitis, pericarditis, endocarditis, and epiglottitis that can cause obstruction of the airway.

Haff disease
(hahf) rhabdomyolysis following consumption of fish of certain types, caused by an as yet unidentified toxin, originally seen among fishermen of the Königsberg (or Frisches) Haff, a lagoon off the Baltic Sea during the 1920s.

hafnium
(Hf) (haf´ne-әm) a chemical element, atomic number 72, atomic weight 178.49.

Hagedorn needles
surgical needles that are flat from side to side, with a straight cutting edge near the point and a large eye.

Hageman factor
factor XII.

Haglund disease
(hahg´loond) bursitis in the region of the Achilles tendon.

Hagner disease
(hahg´nәr) hypertrophic pulmonary osteoarthropathy.

Hahn sign
persistent rotation of the head from side to side in cerebellar disease of childhood.

HAI test
hemagglutination inhibition test.

Hailey-Hailey disease
(ha´le ha´le) benign familial pemphigus.

hair
(hār) any thin, threadlike structure. especially, the specialized epidermal structure produced only by mammals, developing from a papilla sunk in the dermis. The life cycle of a hair (hair cycle) consists of three phases, called anagen, catagen, and telogen. Called also pilus. ...

hair bulb
the bulbous expansion at the proximal end of a hair, in which the hair shaft is generated.

hair cell
a type of sensory cell in the inner ear that has hairlike processes and plays an important role in the process of hearing, having nerve fiber connections to either the cochlear nerve or the vestibular nerve. These cells are found in the organ of Corti, ampullar crest, utricle, and saccule.

hair cycle
the successive phases of the production and then loss of hair, consisting of anagen, catagen, and telogen.

hair disk
a vascularized and innervated area of skin in the connective tissue sheath of a hair follicle, acting as a mechanoreceptor.

hair follicle
one of the tubular invaginations of the epidermis enclosing the hairs, and from which they grow. Folliculus pili (hair follicle). (A), Longitudinal section, comprising the infundibulum, isthmus, stem, and bulb; (B), transverse section of follicle, showing the hair shaft and surrounding follicula...

hair papilla
a fibrovascular dermal papilla enclosed within the hair bulb.

hairball
(hār´bawl) trichobezoar; a concretion of hair sometimes found in the stomach or intestines of humans or other animals.

hairy cell
any of the abnormal cells with a flagellated or hairy appearance found in the blood in hairy cell leukemia.

hairy cell leukemia
a form of chronic leukemia marked by splenomegaly and the large, mononuclear, villus-covered cells called hairy cells in the bone marrow, spleen, liver, and peripheral blood.

hairy tongue
a benign condition of the tongue characterized by hypertrophy of the filiform papillae that gives the dorsum of the tongue a furry appearance. The color of the elongated papillae varies from yellowish white to brown or black, depending upon staining by substances such as tobacco, foods, or drugs.

Hakim syndrome
(hah-kēm´) Hakim-Adams syndrome (hah-kēm´ ad´әmz) (hah-kēm´ ad´әmz) normal-pressure hydrocephalus.

halation
(hal-a´shәn) indistinctness of the visual image caused by strong illumination coming from the same direction as the object being viewed.

halazepam
(hal-az´ә-pam) a benzodiazepine oral antianxiety agent.

halazone
(hal´ә-zōn) a white, crystalline powder used as a disinfectant for water supplies.

Halberstaedter-Prowazek bodies
trachoma bodies.

halcinonide
(hal-sin´ә-nīd) a synthetic corticosteroid used topically as an antiinflammatory and antipruritic in the treatment of certain dermatoses.

Haldane effect
increased oxygenation of hemoglobin promotes dissociation of carbon dioxide; see also Bohr effect.

Haldol
(hal´dol) trademark for a preparation of haloperidol, an antipsychotic agent.

half base syndrome
Garcin syndrome.

half-axial projection
a radiographic projection of the head with the central ray at an angle to the frontal and medial planes; it may be either anteroposterior or posteroanterior. Called also semiaxial projection.

half-life
(haf´līf″) the time required for the decay of half of a sample of particles of a radionuclide or elementary particle; see also radioactivity. Symbol t1/2 or T1/2.

half-time
(haf´tīm) the time required for one half of a quantity of a substance to be eliminated from a system when the substance is eliminated at a rate proportional to its concentration. Symbol t1/2 or T1/2.

half-value layer
the thickness of a given substance that, when introduced in the path of a given beam of rays, will reduce its intensity by one half.

halfway house
(haf´wa hous´) a residence for patients (such as mental patients, drug addicts, or alcoholics) who do not require hospitalization but who need an intermediate degree of care until they can return to the community.

halide
(hal´īd) a compound of a halogen with an element or radical.

halitosis
(hal″ĭ-to´sis) offensive odor of the breath. Transient forms may follow ingestion of strongly flavored food or certain medications; more longer-lasting conditions may be due to disorders of the gums, teeth, other nasopharyngeal structures, lungs, stomach, or liver. Called also fetor oris.

halitus
(hal´ĭ-tәs) exhalation.

Hall sign
a tracheal diastolic shock felt in aneurysm of the aorta.

Hallé point
a point on the surface of the abdomen overlying the site where the ureter crosses the pelvic brim. It is the point of intersection between a horizontal line connecting the anterior superior iliac spines and a vertical line projected superiorly from the pubic spine.

Hallermann-Streiff syndrome
(hah´lәr-mahn shtrīf´) Hallermann-Streiff-François syndrome (hah´lәr-mahn shtrīf´ frahn-swah´) oculomandibulofacial syndrome.

Hallervorden-Spatz disease
(hah´lәr-for″dәn shpahts´) a hereditary disorder involving marked reduction in the number of myelin sheaths of the globus pallidus and substantia nigra; it is characterized by accumulations of iron pigment, progressive rigidity beginning in the legs, choreoathetoid movements, dysarthria, and progressive ment...

Hallion test
Tuffier test.

Hallopeau-Siemens syndrome
(ah-lo-po´ se´mәnz) recessive epidermolysis bullosa dystrophica.

hallucination
(hә-loo″sĭ-na´shәn) a sensory impression (sight, touch, sound, smell, or taste) that has no basis in external stimulation. Hallucinations can have psychologic causes, as in mental illness, or they can result from drugs, alcohol, organic illnesses, such as brain tumor or senility, or exhausti...

hallucinogen
(hә-loo´sĭ-no-jen″) a chemical agent capable of producing hallucinations, such as LSD, mescaline, or psilocybin. Certain mushrooms, seeds, and cactus parts are also hallucinogens. The experiences brought about by the use of hallucinogens involve a more acute “awareness” of one's environment ...

hallucinogenesis
(hә-loo″sĭ-no-jen´ә-sis) the production of hallucinations.

hallucinosis
(hә-loo″sĭ-no´sis) a state characterized by hallucinations without other impairment of consciousness. adj. hallucinot´ic., adj. organic hallucinosis in a former system of classification, a term used for an organic mental syndrome characterized by hallucinations c...

hallux
(hal´әks) pl. hal´luces Latin word meaning the great toe.

hallux dolorosus
(hal´әks do″lә-ro´sәs) a painful disease of the great toe, usually associated with flatfoot.

hallux flexus
(hal´әks flek´sәs) hallux rigidus.

hallux malleus
(hal´әks mal´e-әs) hammer toe affecting the great toe.

hallux rigidus
(hal´әks rij´ĭ-dәs) painful flexion deformity of the great toe with limitation of motion at the metatarsophalangeal joint.

hallux valgus
(hal´әks val´gәs) angulation of the great toe toward the other toes of the foot.

hallux varus
(hal´әks var´әs) angulation of the great toe away from the other toes of the foot.

halo
(ha´lo) a circular structure, such as a luminous circle seen surrounding an object or light. Fick halo a colored circle appearing around a light, experienced by wearers of contact lenses. halo glaucomatosus , glaucomatous halo a narrow ligh...

halo nevus
a melanocytic nevus surrounded by a ring of depigmentation; a minority may be related to development of melanoma.

halo orthosis
a metal cervical orthosis used for traction in the treatment of injuries to the cervical spinal cord. The halo apparatus can maintain stability and alignment of the cervical vertebrae while the patient is out of bed. Called also halo ring.

halo ring
halo orthosis.

halobetasol
(hal″o-ba´tә-sol) a very high potency synthetic corticosteroid used topically in the form of the propionate as an antiinflammatory and antipruritic agent.

halofantrine
(hal″o-fan´trēn) an antimalarial agent used as the hydrochloride salt in treatment of acute malaria due to Plasmodium falciparum or P. vivax.

halogen
(hal´ә-jәn) (ha´lә-jәn) an element of group VII of the periodic table, the members of which form similar (saltlike) compounds in combination with sodium. The halogens are bromine, chlorine, fluorine, iodine, and astatine.

halogen acne
acne due to ingestion of salts of bromine, chlorine, or iodine, such as in cold remedies, expectorants, sedatives, analgesics, or vitamin supplements. See bromide acne, chloracne, and iodide acne.

halometer
(hә-lom´ә-tәr) an instrument for measuring ocular halos. an instrument for estimating the size of erythrocytes by measuring the halos formed around them when a beam of light shines on them and is diffracted.

haloperidol
(hal″o-per´ĭ-dol) an antipsychotic agent of the butyrophenone group; used for the management of symptoms of psychoses and for control of the vocal utterances and tics of Gilles de la Tourette syndrome.

halophil
(hal´o-fil) a microorganism that requires a high concentration of salt for optimal growth.

halophilic
(hal″o-fil´ik) pertaining to or characterized by an affinity for salt; requiring a high concentration of salt for optimal growth.

haloprogin
(hal″o-pro´jin) a synthetic topical antifungal agent used in the treatment of tinea.

Halotestin
(hal″o-tes´tin) trademark for a preparation of fluoxymesterone, an androgen used in the palliative treatment of metastatic breast cancer and in replacement therapy for male hypogonadism and delayed male puberty.

halothane
(hal´o-thān) an inhalational anesthetic used for induction and maintenance of general anesthesia.

Halsted mastectomy
radical mastectomy.

Halsted operation
radical mastectomy.

Halsted suture
a modification of the Lembert suture, consisting of a stitch parallel to the wound on one side, with the two free ends of the material emerging on the other side, where they are tied. See Plate 47.

Haltia-Santavuori disease
(hahl´te-ah sahn″tah-vwo´re) a rare infantile form of neuronal ceroid-lipofuscinosis, beginning about one year of age, with excessive storage of lipofuscin, failure to thrive, myoclonic seizures, muscular hypotonia, psychomotor developmental delay and deterioration, blindness with optic atrophy and cerebellar atax...

Ham test
(ham) one for paroxysmal nocturnal hemoglobinuria, performed by incubating red blood cells in an acid environment; a positive test may be obtained in other forms of anemia.