| transmural | Through any wall, as of the body or of a cyst or any hollow structure. Origin: trans-+ L. Murus, wall (05 Mar 2000) |
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| transmural myocardial infarction | Infarction that involves the whole thickness of the heart muscle from endocardium to epicardium. Synonym: through-and-through myocardial infarction. (05 Mar 2000) |
| transmural pressure | Pressure across the wall of a cardiac chamber or of a blood vessel. In the heart, transmural pressure is the resultant of the intracavitary pressure minus the extracavitary (i.e., pericardial) pressure and is the distending, i.e., true filling, pressure of the cardiac chamber of measurement when this is done during diastole. Since the pericardial pressure normally approximates zero, the filling pressure (usually equal to ventricular diastolic mean pressure), obviating the complexities of measuring pericardial pressure. (05 Mar 2000) |
| transmutation | <radiobiology> Transformation of atoms of one element into atoms of another element via nuclear reactions. (for example, the transmutation of uranium-238 into plutonium-239 via the absorption of a neutron and subsequent beta emission.) (09 Oct 1997) |
| transneuronal atrophy | An atrophy of nerve cells following damage to the axons that make synaptic connection with them; noted especially in the lateral geniculate body. Synonym: transneuronal atrophy, transsynaptic chromatolysis. (05 Mar 2000) |
| transnexus channel | A hexagonal 15-20A |
| transocular | Across the eye. (05 Mar 2000) |
| transom | 1. A horizontal crossbar in a window, over a door, or between a door and a window above it. Transom is the horizontal, as mullion is the vertical, bar across an opening. 2. One of the principal transverse timbers of the stern, bolted to the sternpost and giving shape to the stern structure; called also transsummer. 3. The piece of wood or iron connecting the cheeks of some gun carriages. 4. <surgery> The vane of a cross-staff. 5. One of the crossbeams connecting the side frames of a truck with each other. Transom knees A window divided horizontally by a transom or transoms. A window over a door, with a transom between. Origin: Probably fr. L. Transtrum a crossbeam, transom, from trans across. Cf. Trestle. Source: Websters Dictionary (01 Mar 1998) |
| transonance | Transmission of a sound arising in one organ through another. Origin: trans-+ L. Sonans, sounding (05 Mar 2000) |
| transonic | In ultrasound, describes a region of a relatively unattenuating medium. A distinction should be made between a transonic region and an acoustic echo. Origin: trans-+ sonic (05 Mar 2000) |
| transorbital leukotomy | Lobotomy by an approach through the roof of the orbit, behind the frontal sinus. Synonym: transorbital leukotomy. (05 Mar 2000) |
| transorbital lobotomy | Lobotomy by an approach through the roof of the orbit, behind the frontal sinus. Synonym: transorbital leukotomy. (05 Mar 2000) |
| transosseous venography | Radiographic demonstration of veins that drain a bone's marrow, by injection of contrast medium into the marrow at an appropriate point, as in vertebral venography or azygography by rib injection. (05 Mar 2000) |
| transovarial transmission | Passage of parasites or infective agents from the maternal body to eggs within the ovaries; commonly used to describe certain arthropods, to explain the ability of larvae of the next generation to transmit disease pathogens, as with the infection of larval mites or ticks with rickettsiae or viruses. (05 Mar 2000) |
| transpalatine | <anatomy> Situated beyond or outside the palatine bone; said of a bone in the skull of some reptiles. Origin: Pref. Trans- + palatine. Source: Websters Dictionary (01 Mar 1998) |