| Obersteiner-Redlich line | The narrow line along the course of a nerve (or nerve root) where the Schwann cells and connective tissue that support its axons are replaced by glia cells. The zone marks the true boundary between the central and the peripheral nervous system. Usually located at or near the surface of the spinal cord or brainstem, it can extend (e.g., in the eighth nerve) several millimeters out along the nerve. Synonym: Obersteiner-Redlich line. (05 Mar 2000) |
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| oblique line | A diagonal, sloping or slanting line; a line which is neither parallel nor perpendiculr, neither horizonal nor vertical. See: oblique line of mandible, oblique line of thyroid cartilage. Synonym: linea obliqua. (05 Mar 2000) |
| oblique line of mandible | The line on the external surface of the mandible that extends from the mental tubercle to the ramus and separates the alveolar and basilar parts of the bone. Synonym: linea obliqua mandibulae. (05 Mar 2000) |
| oblique line of thyroid cartilage | A ridge on the outer surface of the thyroid cartilage that gives attachment to the sternothyroid and thyrohyoid muscles. Synonym: linea obliqua cartilaginis thyroidea. (05 Mar 2000) |
| Ogston's line | A line drawn from the adductor tubercle of the femur to the intercondylar notch; a guide to resection of the medial condyle for knock-knee. (05 Mar 2000) |
| Ohngren's line | A theoretical plane passing between the medial canthus of the eye and the angle of the mandible; used as an arbitrary dividing line in classifying localised tumours of the maxillary sinus; tumours above the line invade vital structures early and have a poorer prognosis, whereas those below the line have a more favourable prognosis. (05 Mar 2000) |
| orbitomeatal line | base line |
| temporal line | See: inferior temporal line, superior temporal line. (05 Mar 2000) |
| terminal line | An oblique ridge on the inner surface of the ilium and continued on the pubis, which forms the lower boundary of the iliac fossa; it separates the true from the false pelvis. Synonym: iliopectineal line, terminal line. (05 Mar 2000) |
| Egger's line | Seldom-used term for the circular line of adhesion between the vitreous and posterior lens. (05 Mar 2000) |
| Ehrlich-Turk line | Seldom-used term for the vertical, thin deposition of material on the posterior surface of the cornea in uveitis. (05 Mar 2000) |
| Topinard's line | A line running between the glabella and the mental point. (05 Mar 2000) |
| trapezoid line | The area on the inferior surface of the clavicle near its lateral extremity on which the trapezoid ligament attaches. Synonym: linea trapezoidea, trapezoid ridge. (05 Mar 2000) |
| epiphysial line | The line of junction of the epiphysis and diaphysis of a long bone where growth in length occurs. Synonym: linea epiphysialis, synchondrosis epiphyseos. (05 Mar 2000) |
| established cell line | <cell culture> A cell line is a permanently established cell culture that will proliferate indefinitely given appropriate fresh medium and space. Lines differ from cell strains in that they have escaped the Hayflick limit and become immortalised. Some species, particularly rodents, give rise to lines relatively easily, whereas other species do not. No cell lines have been produced from avian tissues and the establishment of cell lines from human tissue is difficult. Many cell biologists would consider that a cell line is by definition already abnormal and that it is on the way towards becoming the culture equivalent of a neoplastic cell. (26 Mar 1998) |