| middle gray layer of superior colliculus | See: gray layer of superior colliculus. Molecular layer, term applied to any layer of brain tissue that contains few nerve-cell bodies and is composed largely of terminal arborizations of dendrites and axons; notable examples are the superficial layer (first layer) of the cerebral cortex and the molecular layer of cerebellum. Synonym: plexiform layer, stratum moleculare. (05 Mar 2000) |
|---|---|
| middle group of mesenteric lymph nodes | The mesenteric lymph nodes located along the intestinal (jejunal and ileal) branches of the superior mesenteric artery. Synonym: nodi lymphatici superiores centrales, central mesenteric lymph nodes. (05 Mar 2000) |
| middle haemorrhoidal artery | <anatomy, artery> Origin, internal iliac; distribution, middle portion of rectum; anastomoses, inferior rectal and superior rectal. Because the latter is a tributary of the portal system, this is a portosystemic or portocaval anastomosis. Synonym: arteria rectalis media, middle haemorrhoidal artery. (05 Mar 2000) |
| middle haemorrhoidal plexuses | The autonomic plexus's along the rectum derived from the inferior hypogastric plexus. Synonym: plexus rectales medii, middle haemorrhoidal plexuses. (05 Mar 2000) |
| middle haemorrhoidal veins | An obsolete term for middle rectal veins. (05 Mar 2000) |
| middle hepatic veins | Veins draining the central portion of the liver (the superior anterior segment [VIII] and the left side of the inferior anterior segment [V] of the right lobe and the medial segment [IV] of the left lobe) which join to form a trunk that merges with that of the left hepatic veins about 90% of the time prior to entering the left side of the inferior vena cava. Synonym: venae hepaticae mediae. (05 Mar 2000) |
| middle kidney | <anatomy> The middle one of the three pairs of embryonic renal organs developed in most vertebrates; the Wolffian body. Origin: NL, fr. Gr. Middle + kidney. Source: Websters Dictionary (01 Mar 1998) |
| middle lamella | First part of the plant cell wall to be formed, laid down in the phragmoplast during cell division as the cell plate. Subsequently makes up the central part of the double cell wall that separates two adjacent cells, cementing together the two primary walls. Rich in pectin and relatively poor in cellulose. (18 Nov 1997) |
| middle lobe branch | Middle lobe branch of 1) the right pulmonary artery (arteriae pulmonalis dextrae ); 2) the right superior pulmonary vein (venae pulmonalis dextrae superior ). Synonym: ramus lobi medii. (05 Mar 2000) |
| middle lobe of prostate | The portion of the prostate lying between the urethra and the ejaculatory ducts; indistinct unless hypertrophied. Synonym: lobus medius prostatae, Morgagni's caruncle. (05 Mar 2000) |
| middle lobe syndrome | Atelectasis of the right middle pulmonary lobe, with chronic pneumonitis. (12 Dec 1998) |
| middle mediastinal mass | <radiology> Mnemonic: not VD, 90% malignant, Nodes, tumour (metastasis, lymphoma/leukaemia), infection, inhalational disease, Castleman disease, Tumour, primary lung, trachea, oesophagus carcinoma, Vascular, aneurysm, haematoma, Duplication cyst, bronchogenic, enteric, neurenteric (12 Dec 1998) |
| middle mediastinum | The central portion of the inferior mediastinum which contains the pericardium and its contents and the phrenic nerves and accompanying vessels. Synonym: mediastinum medium. (05 Mar 2000) |
| middle meningeal artery | Origin, maxillary; branches, petrosal, superior tympanic, frontal and parietal; distribution, to parts mentioned and through terminal branches to anterior and middle cranial fossae; anastomoses, meningeal branches of occipital, ascending pharyngeal, ophthalmic and lacrimal, stylomastoid, accessory meningeal branch of maxillary, and deep temporal. Synonym: arteria meningea media. (05 Mar 2000) |
| middle meningeal artery groove | A narrow groove on the inner table of the calvarium, seen on lateral radiographs as a thin dark line, which may be mistaken for a skull fracture. See: sulci arteriosi. (05 Mar 2000) |