| retroperitoneal liposarcoma | <radiology> Most common primary retroperitoneal tumour, rarely arises from lipoma, 95% of all fatty retroperitoneal tumours, 40-60 years; M>F, most radiosensitive sarcoma (32% 5-year survival) findings, CT, contrast enhancement, mixed density (fat and soft tissue elements), pseudocystic pattern: water density secondary to volume averaging, angio: hypovascular; no vessel dilation, capillary staining, laking sites for liposarcoma: lower extremity 45%, abdominal cavity and retroperitoneum 14%, trunk 14%, upper extremity 8%, head and neck 7% (12 Dec 1998) |
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| retroperitoneal space | An area occupying the most posterior aspect of the abdominal cavity. It is bounded laterally by the borders of the quadratus lumborum muscles and extends from the diaphragm to the brim of the true pelvis, where it continues as the pelvic extraperitoneal space. (12 Dec 1998) |
| retroperitoneum | Synonym: retroperitoneal space. Origin: retro-+ peritoneum (05 Mar 2000) |
| retroperitonitis | Inflammation of the cellular tissue behind the peritoneum. (05 Mar 2000) |
| retropharyngeal | Posterior to the pharynx. (05 Mar 2000) |
| retropharyngeal abscess | A soft tissue infection of the throat with entry usually by the pharynx but sometimes as an extension of a lateral neck infection resulting from a neck injury. The major risk is upper airway obstruction caused by pharyngeal swelling. (daniel r. Masys, from a written communication) (12 Dec 1998) |
| retropharyngeal lymph nodes | The three groups of lymph nodes, one median and two lateral, located between the pharynx and the prevertebral fascia; they receive lymph from the nasopharynx, the auditory tube, and the atlanto-occipital and atlantoaxial joints. Synonym: nodi lymphatici retropharyngeales. (05 Mar 2000) |
| retropharyngeal space | That part of the peripharyngeal spatium located posterior to the pharynx. In the normal adult it measures 4 mm (at C3 level), but is considered abnormal when greater than 7 mm. Can be icreased with a cervical spine fracture, retropharyngeal abscess. Synonym: spatium retropharyngeum, postpharyngeal space. (21 Jun 2000) |
| retropharynx | <anatomy> The posterior part of the pharynx. (05 Mar 2000) |
| retroplacental | <anatomy> Behind the placenta. (05 Mar 2000) |
| retroplasia | <cell biology> That state of cell or tissue in which activity is decreased below that considered normal. Often associated with retrogressive changes (e.g., injury, degeneration, death, necrosis). Origin: retro-+ G. Plasis, a molding (05 Mar 2000) |
| retropneumoperitoneum | <surgery> Pathological or accidental introduction of air into the retroperitoneal space. (12 Dec 1998) |
| retroposed | Denoting retroposition. Origin: retro-+ L. Pono, pp. Positus, to place (05 Mar 2000) |
| retroposition | Simple backward displacement of a structure or organ, as the uterus, without inclination, bending, retroversion, or retroflexion. Origin: retro-+ L. Positio, a placing (05 Mar 2000) |
| retroposon | A transposition of sequences in a DNA that does not originate in the DNA but, in an mRNA that is transcribed back into the genomic DNA by reverse transcription. Origin: retro-+ L. Pono, pp. Positum, to place, + -on (05 Mar 2000) |