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Medical Dictionary - Dictionary of Medicine and Human Biology |
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Medical Dictionaryhaliphagia (hal-i-fa′je-a) Ingestion of an excessive quantity of a salt or salts, especially of sodium chloride, calcium, magnesium, or potassium salts, or of sodium bicarbonate. [G. hals, salt, + phago, to eat] halisteresis (ha-lis-ter-e′sis) A deficiency of lime salts in the bones. SYN: halosteresis. [G. hals, salt, + steresis, privation, fr. stereo, to deprive] halisteretic (ha-lis-ter-et′ik) Relating to or marked by halisteresis. halitosis (hal-i-to′sis) A foul odor from the mouth. SYN: fetor oris, ozostomia, stomatodysodia. [L. halitus, breath, + G. -osis, condition] halitus (hal′i-tus) Any exhalation, as of a breath or vapor. [L., fr. halo, to breathe] hallachrome (hal′a-krom) A quinone intermediate, derived from l-dopa, in the formation of melanin from l-tyrosine. Hallé Adrien J.M.N., French physician, 1859–1947. See Hallé point. Haller Albrecht von, Swiss physiologist, 1708–1777. See H. ansa, H. anulus, H. arches, under arch, H. circle, H. cones, under cone, H. habenula, H. insula, H. line, H. plexus, H. rete, H. vascular tissue, H. tripod, H. tunica vasculosa, H. unguis, H. vas aberrans. Hallermann Wilhelm, German ophthalmologist, 1901–1976. See H.-Streiff syndrome, H.-Streiff-François syndrome. Hallervorden Julius, German neurologist, 1882–1965. See H. syndrome, H.-Spatz disease, H.-Spatz syndrome. hallex, pl .hallices (hal′eks, hal′i-sez) SYN: great toe I. [L.] Hallgren Bertil, 20th century Swedish geneticist. See H. syndrome. Hallopeau François H., French dermatologist, 1842–1919. See H. disease. Hallpike C.S., 20th century British otologist. See Dix-H. maneuver. hallucal (hal′oo-kal) Relating to the hallux. hallucination (ha-loo′si-na′shun) The apparent, often strong subjective perception of an object or event when no such stimulus or situation is present; may be visual, auditory, olfactory, gustatory, or tactile. [L. alucinor, to wander in mind] auditory h. a symptom frequently observed in a schizophrenic disorder consisting, in the absence of an external source, of hearing a voice or other auditory stimulus that other individuals do not perceive. command h. a symptom, usually auditory but sometimes visual, consisting of a message, from no external source, to do something. formed visual h. h. composed of scenes, often landscapes. gustatory h. the sensation of taste in the absence of a gustatory stimulus; may be seen in temporal lobe epilepsy. haptic h. the sensation of touch in the absence of stimuli; may be seen in alcoholic delirium tremens. hypnagogic h. h. occurring when going to sleep in the period between wakefulness and sleep; one of the components of narcolepsy. hypnopompic h. vivid hallucinations that occur when wakening from sleep; occurs with narcolepsy, but grouped with hypnagogic h.. kinesthesia h. the sense of movement of one or more muscles, when no movement is taking place. lilliputian h. h. of reduced size of objects or persons. mood-congruent h. h. in which the content is mood appropriate. mood-incongruent h. h. that is not consistent with external stimuli; content is not consistent with either manic or depressed mood. olfactory h. false perception in smell. stump h. SYN: phantom limb pain. tactile h. false perception of movement or sensation, as from an amputated limb, or crawling sensation on the skin. unformed visual h. h. composed of sparks, lights, or bursting spheres of light. hallucinogen (ha-loo′si-no-jen) A mind-altering chemical, drug, or agent, specifically a chemical whose most prominent pharmacologic action is on the central nervous system ( e.g., mescaline); in normal subjects, it elicits optical or auditory hallucinations, depersonalization, perceptual disturbances, and disturbances of thought processes. SYN: psychedelic drug, psychodysleptic drug, psycholytic drug, psychotomimetic drug. [L. alucinor, to wander in mind, + G. -gen, producing] hallucinogenesis (ha-loo′si-no-jen′e-sis) The process of producing an hallucination. hallucinogenic (ha-loo′si-no-jen′ik) SYN: psychedelic. hallucinosis (ha-loo-si-no′sis) A syndrome, usually of organic origin, characterized by more or less persistent hallucinations e.g., alcoholic h.. organic h. the state of experiencing a false sensory perception in the absence of external stimulus observed in individuals with one of the organic mental disorders ( e.g., the frightening sensations experienced in alcoholic h. or by a person who has ingested LSD or another of the mind-altering drugs). See hallucination. hallus (hal′us) SYN: great toe I. hallux, pl .halluces (hal′uks, hal′u-sez) [TA] SYN: great toe I. [a Mod. L. form for L. hallex (hallic-), great toe] h. dolorosus a condition, usually associated with flatfoot, in which walking causes severe pain in the metatarsophalangeal joint of the great toe. SYN: painful toe. h. extensus a deformity in which the great toe is held rigidly in the extended position. h. flexus SYN: h. malleus. h. malleus hammer toe involving the first toe. SYN: h. flexus. h. rigidus a condition in which stiffness appears in the first metatarsophalangeal joint; usually associated with the development of bone spurs on the dorsal surface. SYN: stiff toe. h. valgus a deviation of the tip of the great toe, or main axis of the toe, toward the outer or lateral side of the foot. h. varus deviation of the main axis of the great toe to the inner side of the foot away from the second toe. halo (ha′lo) 1. A reddish yellow ring surrounding the optic disk, due to a widening of the scleral ring making the deeper structures visible. 2. An annular flare of light surrounding a luminous body or a depigmented ring around a mole. See h. nevus. 3. SYN: areola (4) . 4. A circular metal band used in a h. cast or h. brace, attached to the skull with pins. [G. halos, threshing floor on which oxen trod a circle; the h. round the sun or moon] anemic h. pale, relatively avascular areas in the skin seen around vascular spiders, cherry angiomas, and sometimes in acute macular eruptions. glaucomatous h. 1. a yellowish white ring surrounding the optic disk, indicating atrophy of the choroid in glaucoma; SYN: glaucomatous ring. 2. a h. surrounding lights, caused by corneal edema in glaucoma. SYN: rainbow symptom. senile h. circumpapillary h. seen in choroidal atrophy of the aged. haloalkylamines (hal-o-al-kil′a-menz) A class of drugs, including phenoxybenzamine and diabenamine, which binds so as to alkylate α-adrenergic receptors so that they are irreversibly inactivated. halogen (hal′o-jen) One of the chlorine group (fluorine, chlorine, bromine, iodine, astatine) of elements; halogens form monobasic acids with hydrogen, and their hydroxides (fluorine forms none) are also monobasic acids. [G. hals, salt, + -gen, producing] halogenation (hal′o-je-na′shun) Incorporation of one or more halogen atoms into a molecule. halogenoderma (hal-o-gen′o-der-ma) Dermatosis caused by ingestion or injection of halogens, most notably bromides and iodides. [halogen + G. derma, skin] Halogeton (hal-o-je′ton) A genus of plants (family Chenopodiaceae) on range lands in the western U.S. and other arid regions of the world; it causes poisoning in cattle and sheep because of the presence of soluble oxalates. halometer (hal-om′e-ter) An instrument used to measure the diffraction halo of a red blood cell; based on the premise that the halo of the large erythrocyte of pernicious anemia is smaller than that of the normal cell; the hazy colorless halo of normal size is characteristic of secondary anemia. halophil, halophile (hal′o-fil, -fil) A microorganism whose growth is enhanced by or dependent on a high salt concentration. [G. hals, salt, + philos, fond] halophilic (hal-o-fil′ik) Requiring a high concentration of salt for growth. halosteresis (ha-los-te-re′sis) SYN: halisteresis. halothane (hal′o-than) A widely used potent nonflammable and nonexplosive inhalation anesthetic, with rapid onset and reversal; side effects include respiratory and cardiovascular depression, and sensitization to epinephrine-induced arrhythmias. Often used in children, as the odor is less pungent than some other anesthetic agents. Halstead Ward C., U.S. psychologist, 1908–1968. See H.-Reitan battery. Halsted William Stewart, U.S. surgeon, 1852–1922. See H. law, H. operation, H. suture. Halteridium (hawl-te-rid′e-um) Former name for Haemoproteus. [G. halteres, weights held in the hand in leaping] halzoun (hal′zun) Local name of a buccopharyngeal infection occurring in Lebanon, probably caused by pentastomid larvae of the dog tongue worm, Linguatula serrata, which wander into the throat of the human host after ingestion of infected raw sheep, or goat liver or lymph nodes. [Ar., snail] Ham Thomas Hale, U.S. physician, 1905–1987. See H. test. ham 1. SYN: popliteal fossa. 2. The buttock and back part of the thigh. [A.S.] HAMA Abbreviation for human antimouse antibody. hamamelis (ham′a-me′lis) A shrub or small tree, H. virginiana (family Harmarmelidaceae), whose bark and dried leaves have been used externally as an application to contusions and other injuries, in headache, and for the cure of noninflammatory hemorrhoids; the water, popularly known as “extract of witch hazel,” is made from the bark and contains 14% alcohol. SYN: witch hazel. [Mod. L., fr. G. hama- melis, fr. hama, together with, + melon, apple] hamartia (ham-ar′she-a) A localized developmental disturbance characterized by abnormal arrangement and/or combinations of the tissues normally present in the area. [G. hamartion, a bodily defect] hamartoblastoma (ha-mar′to-blas-to′ma) A malignant neoplasm of undifferentiated anaplastic cells thought to be derived from a hamartoma. [hamartoma + blastoma] hamartochondromatosis (ham-ar′to-kon′dro-ma-to′sis) Neoplasm-like foci of cartilaginous tissue in sites where cartilage is a normal constituent, but in which the growth of cartilage cells is out of proportion to the other elements of the organ. [G. hamartion, bodily defect, + chondros, cartilage, + -osis, condition] hamartoma (ham-ar-to′ma) A focal malformation that resembles a neoplasm, grossly and even microscopically, but results from faulty development in an organ; composed of an abnormal mixture of tissue elements, or an abnormal proportion of a single element, normally present in that site, which develop and grow at virtually the same rate as normal components, and are not likely to result in compression of adjacent tissue (in contrast to a neoplasm). [G. hamartion, a bodily defect, + -oma, tumor] fibrous h. of infancy a tumor appearing usually in the upper arm or shoulder in the first two years of life and consisting of cellular fibrous tissue infiltrating the subcutis. pulmonary h. h. of the lung, producing a coin lesion composed primarily of cartilage and bronchial epithelium. hamartomatous (ham-ar-to′ma-tus) Relating to hamartoma. hamartophobia (ham′ar-to-fo′be-a) Morbid fear of error or sin. [G. hamartia, fault, + phobos, fear] hamate See h. (bone). hamatum (ha-ma′tum) SYN: hamate (bone). [L. neut. of hamatus, hooked, fr. hamus, a hook] Hamburger Hartog J., Dutch physiologist, 1859–1924. See H. phenomenon. Hamman Louis, U.S. physician, 1877–1946. See H. disease, H. murmur, H. sign, H. syndrome, H.-Rich syndrome. Hammarsten Olof, Swedish physiological chemist, 1841–1932. See H. reagent. hammer (ham′er) SYN: malleus. Hammerschlag Albert, Austrian physician, 1863–1935. See H. method. Hammond William A., U.S. neurologist, 1828–1900. See H. disease. Hampton Aubrey Otis, U.S. radiologist, 1900–1955. See H. line, H. maneuver, H. technique, H. hump. hamster Any of four genera (subfamily Cricetinae, family Muridae) of small rodents widely used in research and as pets: Cricetus, Cricetulus, Mesocricetus, and Phodopus. All hamsters are seed and plant feeders, store food, hibernate in winter, and breed throughout the year under laboratory conditions. hamstring 1. One of the tendons bounding the popliteal space on either side; the medial h. comprises the tendons of the semimembranosus and semitendinosus muscles; the lateral h. is the tendon of the biceps femoris muscle. H. muscles (a) have origin from the ischial tuberosity, (b) act across (at) both the hip and knee joints (producing extension and flexion, respectively), and (c) are innervated by the tibial portion of the sciatic nerve. The medial h. contributes to medial rotation of the leg at the flexed knee joint, while the lateral h. contributes to lateral rotation. 2. In domestic animals, the combined tendons of the superficial digital flexor, triceps surae, biceps femoris, and semitendinosus muscles which are referred to as the common calcanean tendon (tendo calcaneus communis); it is attached to the tuber calcis of the hock. hamular (ham′u-lar) Hook-shaped; unciform. [L. hamulus, q.v.] hamulus, gen. and pl. hamuli (ham′u-lus, -li) [TA] Any hooklike structure. SYN: hook (2) &star. [L. dim. of hamus, hook] h. cochleae SYN: h. of spiral lamina. lacrimal h. [TA] the hooklike lower end of the lacrimal crest, curving between the frontal process and orbital surface of the maxilla to form the upper aperture of the bony portion of the nasolacrimal canal. SYN: h. lacrimalis [TA] , hamular process of lacrimal bone. h. lacrimalis [TA] SYN: lacrimal h.. h. laminae spiralis [TA] SYN: h. of spiral lamina. h. ossis hamati [TA] SYN: hook of hamate. pterygoid h. [TA] the inferior, hook-shaped extremity of the medial plate of the pterygoid process, which serves as a pulley (trochlea) for the tendon of the tensor veli palati muscle. SYN: hamular process of sphenoid bone, h. pterygoideus. h. pterygoideus SYN: pterygoid h.. h. of spiral lamina [TA] the upper hooklike termination of the bony spiral lamina at the apex of the cochlea. SYN: h. laminae spiralis [TA] , h. cochleae, hook of spiral lamina. Hancock Henry, English surgeon, 1809–1880. See H. amputation. Hand Alfred, U.S. pediatrician, 1868–1949. See H.-Schüller-Christian disease. hand [TA] The portion of the upper limb distal to the radiocarpal joint, comprising the wrist, palm, and fingers. SYN: manus [TA] , main. [A.S.] accoucheur h. position of the h. in tetany or in muscular dystrophy; the fingers are flexed at the metacarpophalangeal joints and extended at the phalangeal joints, with the thumb flexed and adducted into the palm; in resemblance to the position of the physician's h. in making a vaginal examination. SYN: obstetric h.. ape h. a deformity marked by extension of the thumb in the same plane as the palm and fingers. SYN: monkey h., monkey-paw. claw h. clawhand. cleft h. a congenital deformity in which the division between the fingers, especially between the third and fourth, extends into the metacarpal region. SEE ALSO: lobster-claw deformity. SYN: split h.. club h. congenital or acquired angulation deformity of h. associated with partial or complete absence of radius or ulna; usually with intrinsic deformities of the h. in congenital variants. crab h. SYN: erysipeloid. dorsum of h. [TA] the back of the h.. SYN: dorsum manus [TA] . drop h. SYN: wrist-drop. ghoul h. a condition seen in African blacks, probably a manifestation of tertiary yaws, marked by depigmentation of the palms and contraction of the skin which give a clawlike and corpselike appearance to the hands. Marinesco succulent h. edema of the h. with coldness and lividity of the skin, observed in syringomyelia. SYN: main succulente. monkey h. SYN: ape h.. obstetric h. SYN: accoucheur h.. opera-glass h. a deformity of the h. seen in chronic absorptive arthritis, the fingers and wrists being shortened and the covering skin wrinkled into transverse folds; the phalanges appear to be retracted into one another like an opera glass or miniature telescope. simian h. deformity in which there is flattening of the thenar eminence, and the thumb lies adducted and extended; usually due to a median nerve lesion. skeleton h. extension of fingers with atrophy of tissues; occurs in progressive muscular atrophy. spade h. the coarse, thick, square h. of acromegaly or myxedema. split h. SYN: cleft h.. trident h. a h. in which the fingers are of nearly equal length and deflected at the first interphalangeal joint, so as to give a forklike shape; seen in achondroplasia. writing h. a contraction of the h. muscles in parkinsonism, bringing the fingers somewhat into the position of holding a pen. haliphagia (hal-i-fa′je-a) Ingestion of an excessive quantity of a salt or salts, especially of sodium chloride, calcium, magnesium, or potassium salts, or of sodium bicarbonate. [G. hals, salt, + phago, to eat] halisteresis (ha-lis-ter-e′sis) A deficiency of lime salts in the bones. SYN: halosteresis. [G. hals, salt, + steresis, privation, fr. stereo, to deprive] halisteretic (ha-lis-ter-et′ik) Relating to or marked by halisteresis. halitosis (hal-i-to′sis) A foul odor from the mouth. SYN: fetor oris, ozostomia, stomatodysodia. [L. halitus, breath, + G. -osis, condition] halitus (hal′i-tus) Any exhalation, as of a breath or vapor. [L., fr. halo, to breathe] hallachrome (hal′a-krom) A quinone intermediate, derived from l-dopa, in the formation of melanin from l-tyrosine. Hallé Adrien J.M.N., French physician, 1859–1947. See Hallé point. Haller Albrecht von, Swiss physiologist, 1708–1777. See H. ansa, H. anulus, H. arches, under arch, H. circle, H. cones, under cone, H. habenula, H. insula, H. line, H. plexus, H. rete, H. vascular tissue, H. tripod, H. tunica vasculosa, H. unguis, H. vas aberrans. Hallermann Wilhelm, German ophthalmologist, 1901–1976. See H.-Streiff syndrome, H.-Streiff-François syndrome. Hallervorden Julius, German neurologist, 1882–1965. See H. syndrome, H.-Spatz disease, H.-Spatz syndrome. hallex, pl .hallices (hal′eks, hal′i-sez) SYN: great toe I. [L.] Hallgren Bertil, 20th century Swedish geneticist. See H. syndrome. Hallopeau François H., French dermatologist, 1842–1919. See H. disease. Hallpike C.S., 20th century British otologist. See Dix-H. maneuver. hallucal (hal′oo-kal) Relating to the hallux. hallucination (ha-loo′si-na′shun) The apparent, often strong subjective perception of an object or event when no such stimulus or situation is present; may be visual, auditory, olfactory, gustatory, or tactile. [L. alucinor, to wander in mind] auditory h. a symptom frequently observed in a schizophrenic disorder consisting, in the absence of an external source, of hearing a voice or other auditory stimulus that other individuals do not perceive. command h. a symptom, usually auditory but sometimes visual, consisting of a message, from no external source, to do something. formed visual h. h. composed of scenes, often landscapes. gustatory h. the sensation of taste in the absence of a gustatory stimulus; may be seen in temporal lobe epilepsy. haptic h. the sensation of touch in the absence of stimuli; may be seen in alcoholic delirium tremens. hypnagogic h. h. occurring when going to sleep in the period between wakefulness and sleep; one of the components of narcolepsy. hypnopompic h. vivid hallucinations that occur when wakening from sleep; occurs with narcolepsy, but grouped with hypnagogic h.. kinesthesia h. the sense of movement of one or more muscles, when no movement is taking place. lilliputian h. h. of reduced size of objects or persons. mood-congruent h. h. in which the content is mood appropriate. mood-incongruent h. h. that is not consistent with external stimuli; content is not consistent with either manic or depressed mood. olfactory h. false perception in smell. stump h. SYN: phantom limb pain. tactile h. false perception of movement or sensation, as from an amputated limb, or crawling sensation on the skin. unformed visual h. h. composed of sparks, lights, or bursting spheres of light. hallucinogen (ha-loo′si-no-jen) A mind-altering chemical, drug, or agent, specifically a chemical whose most prominent pharmacologic action is on the central nervous system ( e.g., mescaline); in normal subjects, it elicits optical or auditory hallucinations, depersonalization, perceptual disturbances, and disturbances of thought processes. SYN: psychedelic drug, psychodysleptic drug, psycholytic drug, psychotomimetic drug. [L. alucinor, to wander in mind, + G. -gen, producing] hallucinogenesis (ha-loo′si-no-jen′e-sis) The process of producing an hallucination. hallucinogenic (ha-loo′si-no-jen′ik) SYN: psychedelic. hallucinosis (ha-loo-si-no′sis) A syndrome, usually of organic origin, characterized by more or less persistent hallucinations e.g., alcoholic h.. organic h. the state of experiencing a false sensory perception in the absence of external stimulus observed in individuals with one of the organic mental disorders ( e.g., the frightening sensations experienced in alcoholic h. or by a person who has ingested LSD or another of the mind-altering drugs). See hallucination. hallus (hal′us) SYN: great toe I. hallux, pl .halluces (hal′uks, hal′u-sez) [TA] SYN: great toe I. [a Mod. L. form for L. hallex (hallic-), great toe] h. dolorosus a condition, usually associated with flatfoot, in which walking causes severe pain in the metatarsophalangeal joint of the great toe. SYN: painful toe. h. extensus a deformity in which the great toe is held rigidly in the extended position. h. flexus SYN: h. malleus. h. malleus hammer toe involving the first toe. SYN: h. flexus. h. rigidus a condition in which stiffness appears in the first metatarsophalangeal joint; usually associated with the development of bone spurs on the dorsal surface. SYN: stiff toe. h. valgus a deviation of the tip of the great toe, or main axis of the toe, toward the outer or lateral side of the foot. h. varus deviation of the main axis of the great toe to the inner side of the foot away from the second toe. halo (ha′lo) 1. A reddish yellow ring surrounding the optic disk, due to a widening of the scleral ring making the deeper structures visible. 2. An annular flare of light surrounding a luminous body or a depigmented ring around a mole. See h. nevus. 3. SYN: areola (4) . 4. A circular metal band used in a h. cast or h. brace, attached to the skull with pins. [G. halos, threshing floor on which oxen trod a circle; the h. round the sun or moon] anemic h. pale, relatively avascular areas in the skin seen around vascular spiders, cherry angiomas, and sometimes in acute macular eruptions. glaucomatous h. 1. a yellowish white ring surrounding the optic disk, indicating atrophy of the choroid in glaucoma; SYN: glaucomatous ring. 2. a h. surrounding lights, caused by corneal edema in glaucoma. SYN: rainbow symptom. senile h. circumpapillary h. seen in choroidal atrophy of the aged. haloalkylamines (hal-o-al-kil′a-menz) A class of drugs, including phenoxybenzamine and diabenamine, which binds so as to alkylate α-adrenergic receptors so that they are irreversibly inactivated. halogen (hal′o-jen) One of the chlorine group (fluorine, chlorine, bromine, iodine, astatine) of elements; halogens form monobasic acids with hydrogen, and their hydroxides (fluorine forms none) are also monobasic acids. [G. hals, salt, + -gen, producing] halogenation (hal′o-je-na′shun) Incorporation of one or more halogen atoms into a molecule. halogenoderma (hal-o-gen′o-der-ma) Dermatosis caused by ingestion or injection of halogens, most notably bromides and iodides. [halogen + G. derma, skin] Halogeton (hal-o-je′ton) A genus of plants (family Chenopodiaceae) on range lands in the western U.S. and other arid regions of the world; it causes poisoning in cattle and sheep because of the presence of soluble oxalates. halometer (hal-om′e-ter) An instrument used to measure the diffraction halo of a red blood cell; based on the premise that the halo of the large erythrocyte of pernicious anemia is smaller than that of the normal cell; the hazy colorless halo of normal size is characteristic of secondary anemia. halophil, halophile (hal′o-fil, -fil) A microorganism whose growth is enhanced by or dependent on a high salt concentration. [G. hals, salt, + philos, fond] halophilic (hal-o-fil′ik) Requiring a high concentration of salt for growth. halosteresis (ha-los-te-re′sis) SYN: halisteresis. halothane (hal′o-than) A widely used potent nonflammable and nonexplosive inhalation anesthetic, with rapid onset and reversal; side effects include respiratory and cardiovascular depression, and sensitization to epinephrine-induced arrhythmias. Often used in children, as the odor is less pungent than some other anesthetic agents. Halstead Ward C., U.S. psychologist, 1908–1968. See H.-Reitan battery. Halsted William Stewart, U.S. surgeon, 1852–1922. See H. law, H. operation, H. suture. Halteridium (hawl-te-rid′e-um) Former name for Haemoproteus. [G. halteres, weights held in the hand in leaping] halzoun (hal′zun) Local name of a buccopharyngeal infection occurring in Lebanon, probably caused by pentastomid larvae of the dog tongue worm, Linguatula serrata, which wander into the throat of the human host after ingestion of infected raw sheep, or goat liver or lymph nodes. [Ar., snail] Ham Thomas Hale, U.S. physician, 1905–1987. See H. test. ham 1. SYN: popliteal fossa. 2. The buttock and back part of the thigh. [A.S.] HAMA Abbreviation for human antimouse antibody. hamamelis (ham′a-me′lis) A shrub or small tree, H. virginiana (family Harmarmelidaceae), whose bark and dried leaves have been used externally as an application to contusions and other injuries, in headache, and for the cure of noninflammatory hemorrhoids; the water, popularly known as “extract of witch hazel,” is made from the bark and contains 14% alcohol. SYN: witch hazel. [Mod. L., fr. G. hama- melis, fr. hama, together with, + melon, apple] hamartia (ham-ar′she-a) A localized developmental disturbance characterized by abnormal arrangement and/or combinations of the tissues normally present in the area. [G. hamartion, a bodily defect] hamartoblastoma (ha-mar′to-blas-to′ma) A malignant neoplasm of undifferentiated anaplastic cells thought to be derived from a hamartoma. [hamartoma + blastoma] hamartochondromatosis (ham-ar′to-kon′dro-ma-to′sis) Neoplasm-like foci of cartilaginous tissue in sites where cartilage is a normal constituent, but in which the growth of cartilage cells is out of proportion to the other elements of the organ. [G. hamartion, bodily defect, + chondros, cartilage, + -osis, condition] hamartoma (ham-ar-to′ma) A focal malformation that resembles a neoplasm, grossly and even microscopically, but results from faulty development in an organ; composed of an abnormal mixture of tissue elements, or an abnormal proportion of a single element, normally present in that site, which develop and grow at virtually the same rate as normal components, and are not likely to result in compression of adjacent tissue (in contrast to a neoplasm). [G. hamartion, a bodily defect, + -oma, tumor] fibrous h. of infancy a tumor appearing usually in the upper arm or shoulder in the first two years of life and consisting of cellular fibrous tissue infiltrating the subcutis. pulmonary h. h. of the lung, producing a coin lesion composed primarily of cartilage and bronchial epithelium. hamartomatous (ham-ar-to′ma-tus) Relating to hamartoma. hamartophobia (ham′ar-to-fo′be-a) Morbid fear of error or sin. [G. hamartia, fault, + phobos, fear] hamate See h. (bone). hamatum (ha-ma′tum) SYN: hamate (bone). [L. neut. of hamatus, hooked, fr. hamus, a hook] Hamburger Hartog J., Dutch physiologist, 1859–1924. See H. phenomenon. Hamman Louis, U.S. physician, 1877–1946. See H. disease, H. murmur, H. sign, H. syndrome, H.-Rich syndrome. Hammarsten Olof, Swedish physiological chemist, 1841–1932. See H. reagent. hammer (ham′er) SYN: malleus. Hammerschlag Albert, Austrian physician, 1863–1935. See H. method. Hammond William A., U.S. neurologist, 1828–1900. See H. disease. Hampton Aubrey Otis, U.S. radiologist, 1900–1955. See H. line, H. maneuver, H. technique, H. hump. hamster Any of four genera (subfamily Cricetinae, family Muridae) of small rodents widely used in research and as pets: Cricetus, Cricetulus, Mesocricetus, and Phodopus. All hamsters are seed and plant feeders, store food, hibernate in winter, and breed throughout the year under laboratory conditions. hamstring 1. One of the tendons bounding the popliteal space on either side; the medial h. comprises the tendons of the semimembranosus and semitendinosus muscles; the lateral h. is the tendon of the biceps femoris muscle. H. muscles (a) have origin from the ischial tuberosity, (b) act across (at) both the hip and knee joints (producing extension and flexion, respectively), and (c) are innervated by the tibial portion of the sciatic nerve. The medial h. contributes to medial rotation of the leg at the flexed knee joint, while the lateral h. contributes to lateral rotation. 2. In domestic animals, the combined tendons of the superficial digital flexor, triceps surae, biceps femoris, and semitendinosus muscles which are referred to as the common calcanean tendon (tendo calcaneus communis); it is attached to the tuber calcis of the hock. hamular (ham′u-lar) Hook-shaped; unciform. [L. hamulus, q.v.] hamulus, gen. and pl. hamuli (ham′u-lus, -li) [TA] Any hooklike structure. SYN: hook (2) &star. [L. dim. of hamus, hook] h. cochleae SYN: h. of spiral lamina. lacrimal h. [TA] the hooklike lower end of the lacrimal crest, curving between the frontal process and orbital surface of the maxilla to form the upper aperture of the bony portion of the nasolacrimal canal. SYN: h. lacrimalis [TA] , hamular process of lacrimal bone. h. lacrimalis [TA] SYN: lacrimal h.. h. laminae spiralis [TA] SYN: h. of spiral lamina. h. ossis hamati [TA] SYN: hook of hamate. pterygoid h. [TA] the inferior, hook-shaped extremity of the medial plate of the pterygoid process, which serves as a pulley (trochlea) for the tendon of the tensor veli palati muscle. SYN: hamular process of sphenoid bone, h. pterygoideus. h. pterygoideus SYN: pterygoid h.. h. of spiral lamina [TA] the upper hooklike termination of the bony spiral lamina at the apex of the cochlea. SYN: h. laminae spiralis [TA] , h. cochleae, hook of spiral lamina. Hancock Henry, English surgeon, 1809–1880. See H. amputation. Hand Alfred, U.S. pediatrician, 1868–1949. See H.-Schüller-Christian disease. hand [TA] The portion of the upper limb distal to the radiocarpal joint, comprising the wrist, palm, and fingers. SYN: manus [TA] , main. [A.S.] accoucheur h. position of the h. in tetany or in muscular dystrophy; the fingers are flexed at the metacarpophalangeal joints and extended at the phalangeal joints, with the thumb flexed and adducted into the palm; in resemblance to the position of the physician's h. in making a vaginal examination. SYN: obstetric h.. ape h. a deformity marked by extension of the thumb in the same plane as the palm and fingers. SYN: monkey h., monkey-paw. claw h. clawhand. cleft h. a congenital deformity in which the division between the fingers, especially between the third and fourth, extends into the metacarpal region. SEE ALSO: lobster-claw deformity. SYN: split h.. club h. congenital or acquired angulation deformity of h. associated with partial or complete absence of radius or ulna; usually with intrinsic deformities of the h. in congenital variants. crab h. SYN: erysipeloid. dorsum of h. [TA] the back of the h.. SYN: dorsum manus [TA] . drop h. SYN: wrist-drop. ghoul h. a condition seen in African blacks, probably a manifestation of tertiary yaws, marked by depigmentation of the palms and contraction of the skin which give a clawlike and corpselike appearance to the hands. Marinesco succulent h. edema of the h. with coldness and lividity of the skin, observed in syringomyelia. SYN: main succulente. monkey h. SYN: ape h.. obstetric h. SYN: accoucheur h.. opera-glass h. a deformity of the h. seen in chronic absorptive arthritis, the fingers and wrists being shortened and the covering skin wrinkled into transverse folds; the phalanges appear to be retracted into one another like an opera glass or miniature telescope. simian h. deformity in which there is flattening of the thenar eminence, and the thumb lies adducted and extended; usually due to a median nerve lesion. skeleton h. extension of fingers with atrophy of tissues; occurs in progressive muscular atrophy. spade h. the coarse, thick, square h. of acromegaly or myxedema. split h. SYN: cleft h.. trident h. a h. in which the fingers are of nearly equal length and deflected at the first interphalangeal joint, so as to give a forklike shape; seen in achondroplasia. writing h. a contraction of the h. muscles in parkinsonism, bringing the fingers somewhat into the position of holding a pen. handedness (hand′ed-nes) Preference for the use of one hand, most commonly the right, associated with dominance of the opposite cerebral hemisphere; may also be the result of training or habit. (hand′ed-nes) Preference for the use of one hand, most commonly the right, associated with dominance of the opposite cerebral hemisphere; may also be the result of training or habit.
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