| thoracic aortic aneurysm | <radiology> Normal size: 4-5 cm, most aneurysms rupture when more than 10 cm, mean age: 65 years; M:F = 3:1 associated with: hypertension, coronary artery disease, abdominal aortic aneurysm symptoms: substernal, back, shoulder pain (25%), superior vena cava syndrome, dysphagia, stridor, dyspnea, hoarseness see: aortic aneurysm (12 Dec 1998) |
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| thoracic aortic plexus | An autonomic plexus surrounding the thoracic aorta and passing with it through the aortic opening in the diaphragm, to become continuous with the abdominal aortic plexus. Synonym: plexus aorticus thoracicus. (05 Mar 2000) |
| familial aortic ectasia | <cardiology, syndrome> The concurrence as an autosomal dominant trait of bicuspid aortic valve often with premature calcification, ectasia and dissection of the aorta and, rarely, coarctation of the aorta. Superficially resembles the Marfan's syndrome. Synonym: familial aortic ectasia. (05 Mar 2000) |
| familial aortic ectasia syndrome | <cardiology, syndrome> The concurrence as an autosomal dominant trait of bicuspid aortic valve often with premature calcification, ectasia and dissection of the aorta and, rarely, coarctation of the aorta. Superficially resembles the Marfan's syndrome. Synonym: familial aortic ectasia. (05 Mar 2000) |
| abdominothoracic arch | A bell-shaped line defined by the lower end of the sternum and the costal arches on each side, constituting a boundary line between the anterolateral portions of the thoracic and abdominal walls. (05 Mar 2000) |
| alveolar arch of mandible | The free margin of the alveolar process of the mandible. Synonym: arcus alveolaris mandibulae, limbus alveolaris. (05 Mar 2000) |
| alveolar arch of maxilla | The free border of the alveolar process of the maxilla. Synonym: arcus alveolaris maxillae, limbus alveolaris. (05 Mar 2000) |
| anterior arch of atlas | An arch that connects the lateral masses of the atlas anteriorly and articulates with the anterior articular facet of the dens of the axis. Synonym: arcus anterior atlantis. (05 Mar 2000) |
| anterior palatine arch | One of a pair of ridges or folds of mucous membrane passing from the soft palate to the side of the tongue; it encloses the palatoglossus muscle and forms anterior margin of the tonsillar fossa. Also demarcates oral cavity from isthmus of fauces. Synonym: arcus palatoglossus, anterior palatine arch, anterior pillar of fauces, arcus glossopalatinus, glossopalatine arch, glossopalatine fold. (05 Mar 2000) |
| arch | <dentistry> Collectively, either the teeth or the basal bone of either jaw. (08 Jan 1998) |
| arch bar | Any one of several types of wires, bar's, or splints conforming to the arch of the teeth, extending from one side of the arch to the other and located labially, or lingually; used for the treatment of jaw fractures and/or stabilization of injured teeth. (05 Mar 2000) |
| arch length | The amount of space required for the permanent teeth as measured from the mesial aspect of the first molar on one side to the mesial aspect of the first molar on the opposite side, as measured through the contact points along an imaginary line of the dental arch. (05 Mar 2000) |
| arch length deficiency | The difference between the available circumference of the dental arch and that required to accommodate the succedaneous teeth in proper alignment. (05 Mar 2000) |
| arch-loop-whorl system | See: Galton's system of classification of fingerprints. (05 Mar 2000) |
| arch of cricoid cartilage | The narrow part of the cartilage that encircles the air passage anterior to the lamina. Synonym: arcus cartilaginis cricoideae. (05 Mar 2000) |