| LAS | laboratory automation system; lateral amyotrophic sclerosis; laxative abuse syndrome; left anterior-... |
|---|---|
| LASH | left anterior superior hemiblock |
| LSR | lanthanide shift reagent; lecithin/ sphingomyelin ratio; left superior rectus [muscle]; liver/spleen... |
| LSVC | left superior vena cava |
| MSO | management service organization; medial superior olive; medical staff organization |
| recessus paraduodenalis | An occasional recess in the peritoneum to the left of the terminal portion of the duodenum located behind a fold containing the inferior mesenteric vein. Synonym: recessus paraduodenalis, fossa venosa, paraduodenal fossa. (05 Mar 2000) |
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| recessus parotideus | A deep hollow on the side at the sides of the face flanking the posterior aspect of the ramus of the mandible with its attached muscles which is occupied by the parotid gland; it is lined with fascial laminae (the parotid sheath) derived from the investing layer of deep cervical fascia; the structures bounding the space collectively constitute the parotid bed. Surgeons operating in the area take advantage of the fact that the anteroposterior dimensions of the parotid space increase with protrusion of the mandible. Synonym: parotid recess, recessus parotideus. (05 Mar 2000) |
| recessus pharyngeus | A slitlike depression in the membranous (non-muscular) pharyngeal wall extending posterior to the opening of the auditory (eustachian) tube. Synonym: recessus pharyngeus, recessus infundibuliformis, Rosenmuller's fossa, Rosenmuller's recess. (05 Mar 2000) |
| recessus phrenicomediastinalis | The recess of the pleural cavity between the diaphragm and the mediastinum. Synonym: recessus phrenicomediastinalis. (05 Mar 2000) |
| recessus pinealis | A diverticulum from the posterior part of the third ventricle extending back between the posterior commissure and the habenular commissure. Synonym: recessus pinealis. (05 Mar 2000) |
| recessus piriformis | A recess in the anterolateral wall of the nasopharynx on each side of the vestible of the larynx separated from it by the aryepiglottic folds. Synonym: recessus piriformis, piriform recess, piriform sinus. (05 Mar 2000) |
| recessus pleurales | Three recesses of the pleural cavity, one behind the sternum and costal cartilages (costomediastinal recess), one between the diaphragm and chest wall (costodiaphragmatic recess), and one between the diaphragm and mediastinum (phrenicomediastinal recess). Synonym: recessus pleurales, pleural sinuses. (05 Mar 2000) |
| recessus posterior | A deepening of the interpeduncular fossa toward the pons. Synonym: recessus posterior. (05 Mar 2000) |
| recessus retrocaecalis | One of several small pockets sometimes found extending alongside the right margin of the ascending colon near the caecum. Synonym: recessus retrocaecalis, caecal recess. (05 Mar 2000) |
| recessus retroduodenalis | A peritoneal recess occasionally found behind the third part of the duodenum, between it and the aorta. Synonym: recessus retroduodenalis, infraduodenal fossa, retroduodenal fossa. (05 Mar 2000) |
| recessus sacciformis | An extension of the cavity of the distal radioulnar articulation proximad between the two bones, an extension of the capsule of the elbow joint at the neck of the radius. Synonym: recessus sacciformis. (05 Mar 2000) |
| recessus sphenoethmoidalis | A small cleftlike pocket of the nasal cavity above the superior concha into which the sphenoid sinuses drain. Synonym: recessus sphenoethmoidalis. (05 Mar 2000) |
| recessus sphericus | A rounded depression on the inner wall of the vestibule of the labyrinth, lodging the sacculus. Synonym: recessus sphericus, fovea hemispherica, fovea spherica. (05 Mar 2000) |
| recessus splenicus | The extension of the omental bursa toward the hilum of the spleen. Synonym: recessus splenicus, recessus lienalis. (05 Mar 2000) |
| recessus subhepaticus | The part of the peritoneal cavity between the visceral surface of the liver and the transverse colon. Synonym: recessus subhepaticus. (05 Mar 2000) |