| AI | accidental injury; accidentally incurred; adiposity index; aggregation index; allergy and immunology... |
|---|---|
| AP | accessory pathway; accounts payable; acid phosphatase; acinar parenchyma; action potential; active p... |
| Ap4CH | apical four-chamber plane |
| AR | absolute risk; accounts receivable; achievement ratio; actinic reticuloid [syndrome]; active resista... |
| A/R | apical/radial |
| apical complex | A set of anterior structures that characterise one or several developmental stages of members of the protozoan phylum Apicomplexa; includes the following structures, visible by electron microscopy: polar ring, conoid, rhoptries, micronemes, and subpellicular tubules. (05 Mar 2000) |
|---|---|
| apical dendrite | The dendritic process extending from the apex of a pyramidal cell of the cerebral cortex toward the surface. Synonym: apical dendrite. (05 Mar 2000) |
| apical dental foramen | The opening at the apex of the root of a tooth that gives passage to the nerve and blood vessels. Synonym: foramen apicis dentis, apical dental foramen, root foramen. (05 Mar 2000) |
| apical dominance | <plant biology> Growth inhibiting effect exerted by actively growing apical bud of higher plant shoots, preventing the growth of buds further down the shoot. Thought to be mediated by the basipetal movement of auxin from the apical bud. (18 Nov 1997) |
| apical ectodermal ridge | The layer of surface ectodermal cells at the apex of the embryonic limb bud; considered to exert an inductive influence on the condensation of underlying mesenchyme. (05 Mar 2000) |
| apical foramen of tooth | The opening at the apex of the root of a tooth that gives passage to the nerve and blood vessels. Synonym: foramen apicis dentis, apical dental foramen, root foramen. (05 Mar 2000) |
| apical gland | One of the small mixed glands deeply placed near the apex of the tongue on each side of the frenulum. Synonym: glandula lingualis anterior, apical gland, Bauhin's gland, Blandin's gland, Nuhn's gland. (05 Mar 2000) |
| apical granuloma | Chronic nonsuppurative inflammation of periapical tissue resulting from irritation following pulp disease or endodontic treatment. (12 Dec 1998) |
| apical group of axillary lymph nodes | The group of lymph node's located at the apex of the axillary fossa that receive lymphatic drainage from other groups of axillary node's and then drain in turn into the subclavian lymphatic trunk. Synonym: nodi lymphatici axillares apicales. (05 Mar 2000) |
| apical infection | Implantation of microorganisms at the apex of a tooth, usually the result of the migration of microorganisms from the pulp canal through the apical foramen. (05 Mar 2000) |
| apical interstitial lung disease | <radiology> A radiological diagnosis where fibrosis is seen in the apices (upper sections) of the lungs. Likely causes include: cystic fibrosis, ankylosing spondylitis, sarcoidosis, silicosis, eosinophlic granuloma, TB and fungus, particularly aspergillus infection. (25 Jun 1999) |
| apical ligament of dens | A ligament that extends from the apex of the dens of the axis to the anterior margin of the foramen magnum; includes vestiges of notochord. Synonym: ligamentum apicis dentis. (05 Mar 2000) |
| apical lordotic projection | In computed tomography or other imaging techniques requiring reconstruction from multiple projections, an algorithm for calculating the contribution of each voxel of the structure to the measured ray data, in order to generate an image; the oldest and simplest method of image reconstruction. Synonym: apical lordotic projection. (05 Mar 2000) |
| apical meristem | <plant biology> The meristem at the tips of stems and roots. Composed of undifferentiated cells, many of which divide to add to the plant body but the central mass (the quiescent centre) remains inert and only becomes active if the meristem is damaged. Synonym: eumeristem. (18 Nov 1997) |
| apical periodontal cyst | An inflammatory odontogenic cyst derived histogenetically from Malassez' epithelial rests surrounding the root apex of a nonvital tooth. Synonym: periapical cyst, radicular cyst, root end cyst. (05 Mar 2000) |