| aperient | <medicine> Gently opening the bowels; laxative. An aperient medicine or food. Origin: L. Aperiens, p. Pr. Of aperire to uncover, open; ab + parire, parere, to bring forth, produce. Cf. Cover, Overt. Source: Websters Dictionary (01 Mar 1998) |
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| aperiodic | Not occurring periodically. (05 Mar 2000) |
| aperiodic biopolymer | A biopolymer consisting of nonidentical subunits present in a nonperiodic sequence. (05 Mar 2000) |
| aperiosteal amputation | Amputation with removal of periosteum from bone at the site of amputation. (05 Mar 2000) |
| aperistalsis | Absence of peristalsis. (05 Mar 2000) |
| aperitive | A compound that stimulates the appetite. (09 Oct 1997) |
| Apert | Eugene, French paediatrician, 1868-1940. See: Apert's hirsutism, Apert's syndrome. (05 Mar 2000) |
| Apert syndrome | <syndrome> Apert (1906) defined a syndrome characterised by skull malformation (acrocephaly of brachysphenocephalic type) due to the premature closure of the cranial sutures and syndactyly of the hands and feet of a special type (complete distal fusion with a tendency to fusion also of the bony structures). The hand, when all the fingers are webbed, has been compared to a spoon and, when the thumb is free, to an obstetric hand. Two clinical categories are distinguished, a 'typical' acrocephalosyndactyly, to which Apert's name is appropriately applied and other forms lumped together as 'atypical' acrocephalosyndactyly. The feature distinguishing the two types is a middigital hand mass with a single nail common to digits 2-4, found in Apert syndrome and lacking in the others. A frequency of Apert syndrome of 1 in 160,000 births is estimated. Evidence suggests that Apert syndrome results from mutations in the gene encoding fibroblast growth factor receptor-2. Progressive synostosis occurs in the feet, hands, carpus, tarsus, cervical vertebrae, and skull, and proposed 'progressive synosteosis with syndactyly' is possibly a more appropriate designation. Clinical features: flat facies, shallow orbits, hypertelorism, narrow palate, craniosynostosis, brachysphenocephalic acrocephaly, syndactyly, broad thumb, broad great toe, single nail digits 2-4, variable mental retardation, corpus callosum and/or limbic malformations, fused cervical vertebrae. A skull X-ray can confirm the diagnosis. Treatment is surgical. Inheritance: autosomal dominant, paternal age effect. (05 Aug 1998) |
| Apert's hirsutism | Hirsutism caused by a virilizing disorder of adrenocortical origin. (05 Mar 2000) |
| Apert's syndrome | <paediatrics> A usually inherited disorder characterised by premature closing of the cranial suture lines resulting in a peaked shaped head and abnormal facial appearance. Since it is usually autosomal dominant one or both parents also have the disorder. Surgery is used to correct skull and facial abnormalities. Inheritance: autosomal dominant. (29 Dec 1997) |
| apertognathia | An open bite deformity, a type of malocclusion characterised by premature posterior occlusion and absence of anterior occlusion. Synonym: open bite. Origin: L. Apertus, open, + G. Gnathos, jaw (05 Mar 2000) |
| apertometer | Instrument for measuring the angular aperture of a microscope objective. (05 Mar 2000) |
| apertura | Synonym: aperture. Origin: L. Fr. Aperio, pp. Apertus, to open (05 Mar 2000) |
| apertura externa aqueductus vestibuli | The external opening of the vestibular aqueduct on the posterior surface of the petrous part of the temporal bone near the groove for the sigmoid sinus. Synonym: apertura externa aqueductus vestibuli. (05 Mar 2000) |
| apertura externa canaliculi cochleae | The external opening of the cochlear aqueduct on the temporal bone medial to the jugular fossa. Synonym: apertura externa canaliculi cochleae. (05 Mar 2000) |