| 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) |
|---|
| acute aortic dissection | <cardiology> A condition in which a weakened portion of the thoracic aorta begins to tear along the longitudinal axis of the vessel. Symptoms include sudden, severe chest pain that may radiate to the back accompanied by nausea, sweating and difficulty breathing. A common risk factor for this event is atherosclerotic vascular disease and-or hypertension. Advanced cases of syphilis (syphilitic aortitis) can also result in acute thoracic dissection as a complication of infection with Treponema pallidum. (27 Sep 1997) |
|---|---|
| aortic dissection | A pathologic process, characterised by splitting of the media layer of the aorta, which leads to formation of a dissecting aneurysm. Classified according to location as follows: type I involves the ascending aorta, transverse arch, and distal aorta; type II is confined to the ascending aorta; type III extends distally in the descending aorta. (05 Mar 2000) |
| aortic dissection: aetiology | <radiology> Usually degenerative, due to aging, increased risk: hypertension, bicuspic aortic valve, aortic coarctation, pregnancy, connective tissue disorder (Marfan, Ehlers-Danlos), skeletal abnormalities (scoliosis, pectus), mycotic aneurysm, Takayasu (giant cell) arteritis, aortic laceration see also: classification (12 Dec 1998) |
| axillary dissection | <procedure, surgery> Surgical removal of lymph nodes from the armpit. This tissue is then sent to the pathologist to determine if the breast cancer has spread outside of the breast. The number of nodes dissected varies during surgery. (02 Jan 1998) |
| radical neck dissection | The most commonly performed major operation for head and neck malignancies, most of which are squamous cell carcinomas. The neck is opened laterally, the majority of the sternocleidomastoid muscle is removed, as are the regional cervical lymph nodes, the jugular vein, the spinal accessory nerve, the submaxillary gland and most of the parotid gland. There are several modifications. (12 Dec 1998) |
| neck dissection | Surgery to remove lymph nodes and other tissues in the neck. (12 Dec 1998) |
| dissection | 1. The act of dissecting an animal or plant; as, dissection of the human body was held sacrilege till the time of Francis I. 2. The act of separating or dividing for the purpose of critical examination. 3. Anything dissected; especially, some part, or the whole, of an animal or plant dissected so as to exhibit the structure; an anatomical so prepared. Dissection wound, a poisoned wound incurred during the dissection of a dead body. Origin: Cf. F. Dissection. Source: Websters Dictionary (01 Mar 1998) |
| dissection tubercle | Dorsal tubercle of radius, a small prominence on the dorsal aspect of the distal end of the radius lateral to the groove for the extensor pollicis longus tendon; it serves as a trochlea or pulley for the tendon. Synonym: tuberculum dorsale, Lister's tubercle. (05 Mar 2000) |
| intramural oesophageal dissection | <radiology> Submucosal dissecting haematoma, haematemesis, chest pain, double-barreled lumen, Treatment: none (supportive) see: oesophageal trauma (12 Dec 1998) |
| 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) |
| Arneth classification | A classification of the polymorphonuclear neutrophils according to the number of their nuclear lobes. See: Arneth stages. (05 Mar 2000) |
| artificial classification | <zoology> Classification based on convenient or conspicuous diagnostic characters without attention to characters indicating relationship, often a classification based on a single arbitrarily chosen character, rather than an evaluation of the totality of characters. (09 Jan 1998) |
| Black's classification | A classification of cavities of the teeth based upon the tooth surface(s) involved. (05 Mar 2000) |
| Caldwell-Moloy classification | A classification of the variations in the female pelvis; namely gynecoid, android, anthropoid, and platypelloid pelvis, based on the type of the posterior and anterior segments of the inlet. (05 Mar 2000) |