| accessory hemiazygos vein | <anatomy, vein> Formed by the union of the fourth to seventh left posterior intercostal veins, passes along the side of the bodies of the fifth, sixth, and seventh thoracic vertebrae, then crosses the midline behind the aorta, oesophagus, and thoracic duct, and empties into the azygos vein, sometimes in common with the hemiazygos vein. Synonym: vena hemiazygos accessoria, vena azygos minor superior. (05 Mar 2000) |
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| hemiazygos vein | <anatomy, vein> Formed by the merger of the left ascending lumbar vein with the left subcostal vein or a communication from the inferior vena cava, it pierces the left crus of the diaphragm, ascends along the left side of the bodies of the lower thoracic vertebrae, opposite the eighth vertebra, crosses the midline behind the aorta, thoracic duct, and oesophagus, and empties into the azygos vein, sometimes in common with the accessory hemiazygos vein. Synonym: vena hemiazygos, vena azygos minor inferior. (05 Mar 2000) |
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| accessory portion of spinal accessory nerve | <anatomy, nerve> The roots of the accessory nerve which arise from the medulla; the nerve fibres of the cranial root join the intracranial portion of the vagus nerve and are distributed to the pharyngeal plexus, providing the motor innervation of the soft palate (except the tensor veli palati) and the pharynx. Synonym: pars vagalis nervi accessorii, radices craniales, accessory portion of spinal accessory nerve, cranial roots, vagal part of accessory nerve, vagal part. (05 Mar 2000) |
| vena hemiazygos | <anatomy, vein> Formed by the merger of the left ascending lumbar vein with the left subcostal vein or a communication from the inferior vena cava, it pierces the left crus of the diaphragm, ascends along the left side of the bodies of the lower thoracic vertebrae, opposite the eighth vertebra, crosses the midline behind the aorta, thoracic duct, and oesophagus, and empties into the azygos vein, sometimes in common with the accessory hemiazygos vein. Synonym: vena hemiazygos, vena azygos minor inferior. (05 Mar 2000) |
| vena hemiazygos accessoria | <anatomy, vein> Formed by the union of the fourth to seventh left posterior intercostal veins, passes along the side of the bodies of the fifth, sixth, and seventh thoracic vertebrae, then crosses the midline behind the aorta, oesophagus, and thoracic duct, and empties into the azygos vein, sometimes in common with the hemiazygos vein. Synonym: vena hemiazygos accessoria, vena azygos minor superior. (05 Mar 2000) |
| accessory cephalic vein | <anatomy, vein> A variable vein that passes along the radial border of the forearm to join the cephalic vein near the elbow. Synonym: vena cephalica accessoria. (05 Mar 2000) |
| accessory saphenous vein | <anatomy, vein> An occasional vein running in the thigh parallel to the great saphenous vein which it joins just before the latter empties into the femoral vein. Synonym: vena saphena accessoria. (05 Mar 2000) |
| accessory vertebral vein | <anatomy, vein> A vein that accompanies the vertebral vein but passes through the foramen of the transverse process of the seventh cervical vertebra and opens independently into the brachiocephalic vein. Synonym: vena vertebralis accessoria. (05 Mar 2000) |
| accessory | In anatomy, denoting certain muscles, nerves, glands, etc. That are auxiliary or supernumerary to some similar, generally more important thing. Synonym: accessorius. Origin: L. Accessorius, fr. Ac-cedo, pp. -cessus, to move toward (05 Mar 2000) |
| accessory adrenal | An island of cortical tissue separate from the adrenal gland, usually found in the retroperitoneal tissues, kidney, or genital organs. Synonym: adrenal rest. (05 Mar 2000) |
| accessory atrium | <cardiology, embryology> A congenital anomaly characterised by the presence in the atrium of a perforated muscular membrane which separates the atrium into upper and lower chambers. (12 Dec 1998) |
| accessory auricles | Small, fleshy nodules or folds, sometimes with supporting cartilage, occasionally found along the margins of the embryonic branchial clefts. (05 Mar 2000) |
| accessory breast | A milk-secreting gland located elsewhere than at the normal place on the chest and existing in addition to the two usual mammae. Synonym: mamma accessoria, accessory breast, supernumerary mamma. (05 Mar 2000) |
| accessory canal | A channel leading from the root pulp laterally through the dentin to the periodontal tissue; may be found anywhere in the tooth root, but is more common in the apical third of the root. Synonym: lateral canal. (05 Mar 2000) |
| accessory cartilage | A sesamoid cartilage. (05 Mar 2000) |
| accessory chromosome | A chromosome existing without its normal homologous chromosome; at the reduction division of gametogenesis an accessory chromosome is likely to be included in one daughter cell and not in the other, but may be lost completely by lagging behind on the equatorial plate. Synonym: monosome, odd chromosome, unpaired allosome, unpaired chromosome. (05 Mar 2000) |