| root of mesentry | The origin of the mesentery of the small intestine (jejunum and ileum) from the posterior parietal peritoneum; about 9 inches (23 cm.) in length, it extends from the duodenojejunal flexure (just to the left of the midline at the L2 vertebral level) to the ileocaecal junction (iliac fossa). Synonym: radix mesenterii. (05 Mar 2000) |
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| root of nail | The proximal end of the nail, concealed under a fold of skin. Synonym: radix unguis. (05 Mar 2000) |
| root of nose | The upper least protruding portion of the external nose situated between the two orbits. Synonym: radix nasi. (05 Mar 2000) |
| root of penis | The proximal attached part of the penis, including the two crura and the bulb. Synonym: radix penis. (05 Mar 2000) |
| root of tongue | The posterior attached portion of the tongue. Synonym: radix linguae, base of tongue. (05 Mar 2000) |
| root of tooth | That part of a tooth below the neck, covered by cementum rather than enamel, and attached by the periodontal ligament to the alveolar bone. Synonym: radix dentis, radix, root. (05 Mar 2000) |
| root planing | A procedure for smoothing of the roughened root surface or cementum of a tooth after subgingival curettage or scaling, as part of periodontal therapy. (12 Dec 1998) |
| root pressure | <botany> Pressure in the roots which, when the shoot is cut off, will cause liquid to ooze from the root stump, the mechanisms and tissues involved in this process are not clearly understood. (09 Oct 1997) |
| root resection | Excision of the apical portion of a tooth through an opening made in the overlying labial, buccal, or palatal alveolar bone. (12 Dec 1998) |
| root resorption | Resorption in which cementum or dentin is lost from the root of a tooth owing to cementoclastic or osteoclastic activity in conditions such as trauma of occlusion or neoplasms. (12 Dec 1998) |
| root sheath | One of the epidermic layers of the hair follicle: external root sheath is continuous with the stratum basale and stratum spinosum of the epidermis; internal root sheath comprises the cuticle of the internal roots, Huxley's layer, and Henle's layer. (05 Mar 2000) |
| root sprout | <botany> A living shoot which grows from the root of a plant whose above-ground portion has been cut down. (09 Oct 1997) |
| root tip | The tip of a tooth root, the part farthest from the incisal or occlusal side. Synonym: apex radicis dentis, root apex, root tip. (05 Mar 2000) |
| clinical root | That portion of a tooth embedded in the investing structures; the portion of a tooth not visible in the oral cavity. Synonym: radix clinica. (05 Mar 2000) |
| motor root | The motor root of a spinal nerve. Synonym: radix anterior, radix motoria, anterior root, motor root, radix ventralis. (05 Mar 2000) |