| apertura pelvis minoris | The lower opening of the true pelvis, bounded anteriorly by the pubic arch, laterally by the rami of the ischium and the sacrotuberous ligament on either side, and posteriorly by these ligaments and the tip of the coccyx. Synonym: apertura pelvis inferior, apertura pelvis minoris, fourth parallel pelvic plane, pelvic outlet, pelvic plane of outlet, plane of outlet. (05 Mar 2000) |
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| apertura pelvis superior | The upper opening of the true pelvis, bounded anteriorly by the pubic symphysis and the pubic crest on either side, laterally by the iliopectineal lines, and posteriorly by the promontory of the sacrum. Synonym: apertura pelvis superior, aditus pelvis, first parallel pelvic plane, pelvic brim, pelvic inlet, pelvic plane of inlet, plane of inlet. (05 Mar 2000) |
| apertura piriformis | The anterior nasal opening in the skull. Synonym: apertura piriformis, piriform opening. (05 Mar 2000) |
| apertura sinus frontalis | One of a pair of openings in the floor of the frontal sinuses in the nasal part of the frontal bone, through which the frontal sinuses communicate with the ethmoidal infundibulum via the frontonasal duct. Synonym: apertura sinus frontalis. (05 Mar 2000) |
| apertura sinus sphenoidalis | One of the pair of openings in the body of the sphenoid bone through which the sphenoid sinuses communicate with the sphenoethmoidal recess of the nasal cavity. Synonym: apertura sinus sphenoidalis, sphenoidal sinus aperture. (05 Mar 2000) |
| apertura thoracis inferior | The inferior boundary of the bony thorax composed of the twelfth thoracic vertebra and the lower margins of the rib cage and sternum. Synonym: apertura thoracis inferior. (05 Mar 2000) |
| apertura thoracis superior | The upper boundary of the bony thorax composed of the first thoracic vertebra and the upper margins of the first ribs and manubrium of the sternum. Synonym: apertura thoracis superior. (05 Mar 2000) |
| apertura tympanica canaliculi chordae tympani | The small canal opening found lateral to the pyramidal eminence in the posterior wall of the middle ear cavity from which the chorda tympani nerve emerges to pass anteriorly between the ossicles accompanied by a branch of the stylomastoid artery. Synonym: apertura tympanica canaliculi chordae tympani. (05 Mar 2000) |
| aditus ad aqueductum cerebri | Entrance to the cerebral aqueduct (of Sylvius) from the caudal part of the third ventricle. Synonym: aditus ad aqueductum cerebri, Bartholin's anus, opening to cerebral aqueduct. (05 Mar 2000) |
| anus cerebri | Entrance to the cerebral aqueduct (of Sylvius) from the caudal part of the third ventricle. Synonym: aditus ad aqueductum cerebri, Bartholin's anus, opening to cerebral aqueduct. (05 Mar 2000) |
| arteria cerebri anterior | <anatomy, artery> One of the two terminal branches (with middle cerebral artery) of the internal carotid; it passes anterior, loops around the genu of the corpus callosum then posteriorly in the interhemispheric fissure along with its fellow of the opposite side, the two being joined by the anterior communicating artery; for descriptive purposes it is divided into two parts: the precommunical part (A2 segment of clinical terminology), supplying branches to the thalamus and corpus striatum, and the postcommunical part, (A2) or pericallosal artery, supplying branches to the cortex of the medial parts of the frontal and parietal lobes. Synonym: arteria cerebri anterior. (05 Mar 2000) |
| arteria cerebri media | <anatomy, artery> One of the two large terminal branches (with anterior cerebral artery) of the internal carotid artery; it passes laterally around the pole of the temporal lobe, then posteriorly in the depth of the lateral cerebral fissure; for descriptive purposes it is divided into three parts: 1) the sphenoidal part (M1 segment of clinical terminology), supplying perforating branches to the internal capsule, thalamus, and striate body; 2) the insular part, supplying branches to the insula and adjacent cortical areas; and 3) the terminal part or cortical part, supplying a large part of the central cortical convexity (the latter two collectively forming M2 segment). Synonym: arteria cerebri media. (05 Mar 2000) |
| arteria cerebri posterior | <anatomy, artery> Formed by the bifurcation of the basilar artery; it passes around the cerebral peduncle to reach the medial aspect of the hemisphere; for descriptive purposes it is divided into three parts: 1) the precommunical part (P1 segment of clinical terminology), the part before the junction with the posterior communicating artery, supplying parts of the thalamus, hypothalamus, and midbrain; 2) the postcommunical part (P2), supplying the thalamus, cerebral peduncles, and the choroid plexuses of the lateral and third ventricles; and 3) the terminal or cortical part, supplying the cortex of the temporal (P3) and occipital (P4) lobes. Synonym: arteria cerebri posterior. (05 Mar 2000) |
| astrocytosis cerebri | A diffuse intracranial neoplasm of astrocytic origin. Synonym: astrocytosis cerebri, glioblastosis cerebri. (05 Mar 2000) |
| basis cerebri | The inferior surface of the brain visible when seen from below. Synonym: facies inferior cerebri, basis cerebri, inferior cerebral surface. (05 Mar 2000) |