| colon descendens | The fourth portion of the large intestine (colon) that communicates with the transverse colon in the left-upper quadrant of the abdomen and the rectum below. (27 Sep 1997) |
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| descendens | Synonym: descending. Origin: L. (05 Mar 2000) |
| descendens cervicalis | Fibres from the second and third cervical nerves that pass forward and downward along the internal jugular vein; they contribute to the ansa cervicalis and innervate the infrahyoid muscles. Synonym: descendens cervicalis, radix inferior ansae cervicalis. (05 Mar 2000) |
| descendens hypoglossi | The fibres that arise from the first and second cervical nerves, accompany the hypoglossal nerve, then branch off to meet the inferior root in the ansa cervicalis; they innervate the infrahyoid muscles. Synonym: descendens hypoglossi, descending branch of hypoglossal nerve, radix superior ansae cervicalis. (05 Mar 2000) |
| tractus descendens nervi trigemini | <anatomy, nerve> A compact fibre bundle, comma-shaped on transverse section, composed of primary sensory fibres of the portio major of the trigeminal nerve, descending from the level of the entrance of the trigeminus in the upper pons down through the dorsolateral region of the rhombencephalic tegmentum along the lateral side of the descending or spinal nucleus of the trigeminus, emerging on the dorsolateral surface of the lower medulla oblongata as the tuberculum cinereum, and continuing as far as the second cervical segment of the spinal cord. Its fibres are distributed to the descending or spinal nucleus of the trigeminus. Synonym: tractus spinalis nervi trigemini, descending tract of trigeminal nerve, tractus descendens nervi trigemini. (05 Mar 2000) |
| arcus aortae | The curved portion between the ascending and descending parts of the aorta; it begins as a continuation of the ascending aorta posterior to the sternal angle, runs posteriorly and slightly to the left as it passes over the root of the left lung, and becomes the descending aorta as it reaches and begins to course along the vertebral column; it gives rise to the brachiocephalic trunk, the left common carotid and left subclavian arteries. Any member of the several pairs of arterial channels encircling the embryonic pharynx in the mesenchyme of the brachial arches; there are potentially six pairs, but in mammals the fifth pair is poorly developed or absent. The first and second pairs are functional only in very young embryos; the third pair is involved in the formation of the carotids; the fourth arch on the left is incorporated in the arch of the aorta; the sixth pair forms the proximal part of the pulmonary arteries. A series of arterial channels encircling the embryonic pharynx in the mesenchyme of the branchial arch's. There are potentially six pairs, but in mammals the fifth pair is poorly developed or absent. The first and second pairs are functional only in very young embryos; the third pair is involved in the formation of the carotids; the fourth arch on the left is incorporated in the arch of the aorta; the sixth pair forms the proximal part of the pulmonary arteries. Synonym: arcus aortae. (05 Mar 2000) |
| bifurcatio aortae | The division of the aorta into right and left common iliac arteries; it occurs at the level of the fourth and fifth lumbar vertebral body. Synonym: bifurcatio aortae. (05 Mar 2000) |
| bulbus aortae | The dilated first part of the aorta containing the aortic semilunar valves and the aortic sinuses. Synonym: bulbus aortae, arterial bulb. (05 Mar 2000) |
| valva aortae | The heart valve that divides the left ventricle and the aorta. The aortic valve opens during left ventricular contraction and then closes to prohibit the backwash of oxygenated blood from the aorta into the ventricle. The aortic valve has 3 valve cusps. (27 Sep 1997) |
| valvula semilunaris dextra valvae aortae | Right semilunar cusp of the aortic valve. (05 Mar 2000) |
| valvula semilunaris posterior valvae aortae | Posterior semilunar cusp of the aortic valve. (05 Mar 2000) |
| valvula semilunaris sinistra valvae aortae | Left semilunar cusp of the aortic valve. (05 Mar 2000) |
| rami mediastinales aortae thoracicae | Numerous small arteries supplying the pleura and lymph nodes of the posterior mediastinum. Synonym: rami mediastinales aortae thoracicae, posterior mediastinal arteries. (05 Mar 2000) |
| rami oesophageales aortae thoracicae | Branches arising directly from the anterior aspect of the portion of the thoracic aorta adjacent to the oesophagus, by which most of the oesophagus is supplied. Synonym: rami oesophageales aortae thoracicae. (05 Mar 2000) |
| rami pericardiaci aortae thoracicae | Small branches of thoracic aorta distributed to the pericardium, in the region of the oblique pericardial sinus, and to posterior mediastinal lymph nodes. Synonym: rami pericardiaci aortae thoracicae. (05 Mar 2000) |