| median aperture of the fourth ventricle | The large midline opening in the posterior inferior part of the roof of the fourth ventricle, connecting the ventricle with the cerebellomedullary cistern. Synonym: apertura mediana ventriculi quarti, arachnoid foramen, Magendie's foramen, median aperture of the fourth ventricle. (05 Mar 2000) |
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| median arcuate ligament | <anatomy> A tendinous connection between the crura of the diaphragm that arches over the aorta, forming the anterosuperior margin of the aortic hiatus. Synonym: ligamentum arcuatum medianum. (05 Mar 2000) |
| median artery | <anatomy, artery> Origin, anterior interosseous; distribution, accompanies median nerve to palm; anastomoses, branches of superficial palmar arch. Synonym: arteria comitans nervi mediani, arteria mediana. (05 Mar 2000) |
| median atlantoaxial joint | A pivot synovial joint between the dens of the axis and the ring formed by the anterior arch and the transverse ligament of the atlas. Synonym: articulatio atlantoaxialis mediana, Cruveilhier's joint, middle atlantoepistrophic joint. (05 Mar 2000) |
| median bar of Mercier | A prominent band of fibromuscular tissue involving the interureteric ridge or neck of the urinary bladder, occasionally resulting in urinary obstruction. (05 Mar 2000) |
| median basilic vein | <anatomy, vein> The medial branch of the median antebrachial vein which joins the basilic vein. Synonym: vena intermedia basilica, median basilic vein, vena mediana basilica. (05 Mar 2000) |
| median cephalic vein | <anatomy, vein> The lateral branch of the median antebrachial vein that joins the cephalic vein near the elbow. Synonym: vena intermedia cephalica, median cephalic vein, vena mediana cephalica. (05 Mar 2000) |
| median cubital vein | <anatomy, vein> A vein which passes across the anterior aspect of the elbow from the cephalic vein to the basilic vein; commonly this vein is replaced by intermediate basilic and intermediate cephalic veins. The median cubital vein is often used for venipuncture. Synonym: vena intermedia cubiti, intermediate cubital vein, vena mediana cubiti. (05 Mar 2000) |
| median effective dose | The dose that produces the desired effect; when followed by a subscript (generally "ED50"), it denotes the dose having such an effect on a certain percentage (e.g., 50%) of the test animals; ED50 is the median effective dose, in radiation protection, the sum of the equivalent doses in all tissues and organs of the body weighted for tissue effects of radiation. The unit of effective dose is the sievert (Sv), epilation dose, the minimum amount of radiation sufficient to produce hair loss, usually in 10 to 14 days. (05 Mar 2000) |
| median eminence | <anatomy> Raised area on the infundibular hypothalamus at the floor of the third ventricle of the brain which contains the primary capillary network of the hypophyseal portal system. (12 Dec 1998) |
| median frontal sulcus | A relatively shallow sagittal fissure of the brain dividing the middle frontal convolution into an upper and lower part; this sulcus is found only in humans and anthropoid apes; at its anterior extremity it bifurcates, the two branches spreading out laterally and constituting the frontomarginal sulcus. Synonym: median frontal sulcus, sulcus frontalis medius. (05 Mar 2000) |
| median glossoepiglottic fold | <anatomy> A fold of mucous membrane in the midline that extends from the back of the tongue to the epiglottis, forming the medial boundary of the epiglottic valleculae. Synonym: plica glossoepiglottica mediana, frenulum epiglottidis, middle glossoepiglottic fold. (05 Mar 2000) |
| median groove of tongue | <anatomy> Median groove or median longitudinal raphe of tongue; raphe linguae; a slight longitudinal depression running forward on the dorsal surface of the tongue from the foramen caecum. Synonym: sulcus medianus linguae, median longitudinal raphe of tongue, raphe linguae. (05 Mar 2000) |
| median laryngotomy | Operative opening into the larynx, generally through the midline, commonly done for the excision of early carcinoma or the correction of laryngostenosis. Synonym: median laryngotomy, thyrofissure, thyroidotomy, thyrotomy. (05 Mar 2000) |
| median line | <anatomy> See: anterior median line, posterior median line. (05 Mar 2000) |