| 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) |
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| 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 of right lung | It is located anteriorly between the horizontal and oblique fissures and includes lateral and medial bronchopulmonary segments. Synonym: lobus medius pulmonis dextri. (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) |
| middle meningeal branch of maxillary nerve | <anatomy, nerve> Recurrent branch of maxillary nerve distributed with the anterior branch of the middle meningeal arteyr to the meninges of the anterior portion of the middle cranial fossa. Synonym: ramus meningeus medius nervi maxillaris, middle meningeal nerve. (05 Mar 2000) |
| middle meningeal nerve | <anatomy, nerve> Recurrent branch of maxillary nerve distributed with the anterior branch of the middle meningeal arteyr to the meninges of the anterior portion of the middle cranial fossa. Synonym: ramus meningeus medius nervi maxillaris, middle meningeal nerve. (05 Mar 2000) |
| middle meningeal veins | The venae comitantes of the middle meningeal artery that empty into the pterygoid plexus. Synonym: venae meningeae mediae. (05 Mar 2000) |
| middle pain | <gynaecology> One-sided lower abdominal (pelvic) pain that occurs at or around the time of ovulation (midcycle). Thought to be secondary to a stretching of the ovarian capsule and subsequent capsular rupture during expulsion of the egg. Inevitably, there is some bleeding associated with this normal month function that can inflame the peritoneum and cause pain. (27 Sep 1997) |
| middle palmar space | The more medial of the central palmar spaces, bounded medially by the hypothenar compartment; related distally to the synovial tendon sheaths of digits 3 and 4 and proximally to the common flexor sheath. Synonym: medial midpalmar space, middle palmar space. (05 Mar 2000) |
| middle piece | A part of the spermatozoon characterised by an axoneme and by a sheath of mitochondria arranged in a tight helix. Principal piece, the principal part of the spermatozoon, which is about 45 um long and has a characteristic fibrous sheath surrounding the axoneme. (05 Mar 2000) |