| rostral | Relating to any rostrum or anatomical structure resembling a beak. Synonym: rostralis. Origin: L. Rostralis, fr. Rostrum, beak (05 Mar 2000) |
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| rostral lamina | A whitish line appearing on perfectly median sections of the brain as a thin bridge connecting the rostrum of the corpus callosum with the lamina terminalis; the rostral lamina contains no commissural fibres; instead, it corresponds to the line along which the pia mater reflects from the medial surface of one hemisphere to that of the other. Synonym: lamina rostralis, rostral layer, teniola corporis callosi. (05 Mar 2000) |
| rostral layer | A whitish line appearing on perfectly median sections of the brain as a thin bridge connecting the rostrum of the corpus callosum with the lamina terminalis; the rostral lamina contains no commissural fibres; instead, it corresponds to the line along which the pia mater reflects from the medial surface of one hemisphere to that of the other. Synonym: lamina rostralis, rostral layer, teniola corporis callosi. (05 Mar 2000) |
| rostral neuropore | The temporary opening at the extreme rostral (cephalic) end of the early embryonic forebrain; closes at the 20th somite stage. Synonym: anterior neuropore, cranial neuropore. (05 Mar 2000) |
| rostral transtentorial herniation | Displacement of anterior cerebellar structures through the incisura, with or without caudorostral brainstem shift. (05 Mar 2000) |
| partial denture retention | The fixation of a removable partial denture by the use of clasps, indirect retainers, or precision attachments. (05 Mar 2000) |
| retention | 1. The persistent keeping within the body of matters normally excreted. 2. In cavity preparation, the prevention of displacement of a restoration. 3. <dentistry> The period during which the patient is wearing an appliance to maintain and stabilise the teeth in the position into which they were moved. 4. <psychology> The persistence to perform a learned behaviour (facts or experiences) after an interval has elapsed in which there has been no performance or practice of the behaviour. Origin: L. Retentio, from retentare = to hold firmly back (18 Nov 1997) |
| retention area | An area of a tooth provided during its preparation for restoration that will aid in holding the restoration in place. See: retention groove, retention point. (05 Mar 2000) |
| retention arm | A flexible segment of a removable partial denture that engages an undercut on an abutment and is designed to retain the denture. (05 Mar 2000) |
| retention cyst | A cyst resulting from some obstruction to the excretory duct of a gland. Synonym: distention cyst, secretory cyst. (05 Mar 2000) |
| retention form | The shape of a cavity preparation that prevents displacement of the dental restoration by lateral or tipping forces as well as masticatory forces. (05 Mar 2000) |
| retention groove | One of the groove's forming opposing vertical constrictions in a tooth to aid in retention of a dental restoration. (05 Mar 2000) |
| retention jaundice | Jaundice due to insufficiency of liver function or to an excess of bile pigment production; the bilirubin is unconjugated because it has not passed through the liver cells; van den Bergh test is indirect. (05 Mar 2000) |
| retention point | A provision made within a cavity preparation of a tooth to hold in place the first pieces of gold when placing a direct gold restoration. (05 Mar 2000) |
| retention polyp | A smoothly rounded mucosal hamartoma of the large bowel, which may be multiple and cause rectal bleeding, especially in the first decade of life; it is not precancerous. Synonym: retention polyp. (05 Mar 2000) |