| 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) |
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| 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) |
| apical periodontitis | Inflammation of the periodontal ligament surrounding the root apex of a tooth; usually a consequence of pulpal inflammation or necrosis. (05 Mar 2000) |
| apical plasma membrane | <cell biology> The term used for the cell membrane on the apical (inner or upper) surface of transporting epithelial cells. This region of the cell membrane is separated, in vertebrates, from the baso lateral membrane by a ring of tight junctions that prevents free mixing of membrane proteins from these two domains. (18 Nov 1997) |
| apical process | 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 segment | Apical segment of the superior lobe of the right lung, apical segment of the inferior lobe of the right and left lungs. Synonym: segmentum superius. Synonym: segmentum superius, segmentum apicale, superior segment. (05 Mar 2000) |
| apical space | The space between the alveolar wall and the apex of the root of a tooth where an alveolar abscess usually has its origin. (05 Mar 2000) |
| late apical systolic murmur | A murmur previously considered benign, or even extracardiac, with a possible relationship to pericardial disease; it often represents mitral insufficiency, often localised and of moderate severity but with propensity for developing bacterial endocarditis, and is frequently associated with systolic click and mitral prolapse (Barlow syndrome; a balloon or billowing mitral valve leaflet) often producing a click, murmur, or both, as it prolapses during systole into the left atrium. (05 Mar 2000) |
| anastomotic branch of middle meningeal artery to lacrimal artery | <anatomy, artery> A branch of the middle meningeal artery arising in the cranial cavity which runs anteriorly through the superior orbital fissure to anastomose with the lacrimal artery. See: orbital branch of middle meningeal artery. Synonym: ramus anastomoticus arteriae meningeae mediae cum lacrimali. (05 Mar 2000) |
| Abbott's artery | <anatomy, artery> An anomalous artery arising from the posteromedial proximal descending aorta, important during coarctation repair. (05 Mar 2000) |
| aberrant artery | Artery having an unusual origin or course. (05 Mar 2000) |
| aberrant obturator artery | See: pubic branch of inferior epigastric artery. (05 Mar 2000) |
| accessory meningeal branch of middle meningeal artery | <anatomy, artery> A branch of either the middle meningeal or maxillary artery in the infratemporal fossa and passing superiorly through the foramen ovale to supply the trigeminal ganglion, dura mater and inner table of bone. Synonym: ramus meningeus accessorius arteriae meningeae mediae. (05 Mar 2000) |