| horizontal part of duodenum | pars horizontalis duodeni, inferior part of duodenum, pars inferior duodeni |
|---|---|
| horizontal part of facial canal | First portion of facial canal, between beginning of canal (at the introitus of the facial canal at the end of the internal auditory meatus) and the point at which it turns to descend, beginning the descending part. There are two components (crura) of the horizontal part: the medially-located, anteriorly-directed medial crus and the laterally-placed, posteriorly-directed lateral crus, the two being continuous at a sharp bend, the genu of the facial canal. This lateral part is where the genicular ganglion is located and which communicates with the middle cranial fossa via the hiatus of the facial canal, through which the greater superficial petrosal nerve passes. (05 Mar 2000) |
| horizontal plane | A plane across the body at right angles to the coronal and sagittal plane's. Synonym: horizontal plane. (05 Mar 2000) |
| horizontal plate of palatine bone | The part of the palatine bone that forms the posterior part (approximately one third) of the bony palate. Synonym: lamina horizontalis ossis palatini. (05 Mar 2000) |
| horizontal resorption | A progressive loss of alveolar and supporting bone surrounding the teeth, beginning at the most coronal level of the bone. Synonym: horizontal resorption. (05 Mar 2000) |
| horizontal survey | <epidemiology> A study of a community, perhaps stratified by age, sex, ethnicity etc., but at one point in time or over a short time interval. Although a snapshot, horizontal surveys of prevalence and intensity within different age classes of a community can nevertheless provide valuable information on the rate at which hosts acquire infection through time, provided that the host and parasite populations have remained approximately stable for a period of time (i.e. Stable endemicity). Same as cross-sectional study , converse of longitudinal study. (05 Dec 1998) |
| horizontal transmission | <epidemiology> Transmission occurring generally within a population, but not including vertical transmission. (05 Dec 1998) |
| horizontal vertigo | Dizziness experienced on lying down. (05 Mar 2000) |
| disease transmission, horizontal | The transmission of infectious disease or pathogens from one individual to another in the same generation. (12 Dec 1998) |
| transverse horizontal axis | An imaginary line around which the mandible may rotate through the horizontal plane. Synonym: hinge axis, mandibular axis. (05 Mar 2000) |
| lateral crus of horizontal part of the facial canal | Laterally-placed, posteriorly-directed second portion of the horizontal part of the facial canal. See: horizontal part of facial canal. Synonym: lateral crus of horizontal part of the facial canal. (05 Mar 2000) |
| Frankfort horizontal plane | A standard craniometric reference plane passing through the right and left porion and the left orbitale; drawn on the profile radiograph or photograph from the superior margin of the acoustic meatus to the orbitale. Synonym: auriculo-infraorbital plane, eye-ear plane, Frankfort horizontal plane, Frankfort plane, infraorbitomeatal plane. (05 Mar 2000) |
| adansonian classification | The classification of organisms based on giving equal weight to every character of the organism; this principle has its greatest application in numerical taxonomy. Origin: M. Adanson (05 Mar 2000) |
| Angle's classification of malocclusion | A classification of different types of malocclusion, based on the mesiodistal relationship of the permanent molars upon their eruption and locking, and comprised of three classes; Class I: normal relationship of the jaws, wherein the mesiobuccal cusp of the maxillary first molar occludes in the buccal groove of the mandibular first permanent molar; Class II: distal relationship of the mandible, wherein the distobuccal cusp of the maxillary first permanent molar occludes in the buccal groove of the mandibular first molar, and further classified as Division 1, labioversion of maxillary incisor teeth, and Division 2, linguoversion of maxillary central incisors, both of which may be unilateral conditions; Class III: mesial relationship of the mandible, wherein the mesiobuccal cusp of the maxillary first molar occludes in the embrasure between the mandibular first and second permanent molars, further classified as a unilateral condition. (05 Mar 2000) |
| aortic dissection: classification | <radiology> DeBakey: I ascending aorta to arch with or without descending aorta (30%), II ascending aorta only (20%), III descending aorta to thoracic aorta (50%), Stanford: A involvement of ascending aorta (regardless of origin), B aortic arch and distal aorta see also: aetiology mnemomics: 1 A.D. (DeBakey), A = Ascending (12 Dec 1998) |