| oblique sinus of pericardium | The recess in the pericardial cavity posterior to the base of the heart bounded laterally by the pericardial reflections on the pulmonary veins and inferior vena cava, and posteriorly by the pericardium overlying the anterior aspect of the oesophagus. Synonym: sinus obliquus pericardii, oblique sinus of pericardium. (05 Mar 2000) |
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| oblique vein of left atrium | A small vein on the posterior wall of the left atrium which merges with the great cardiac vein to form the coronary sinus; it is developed from the left common cardinal vein, and occasionally persists as a left superior vena cava. Synonym: vena obliqua atrii sinistri, Marshall's oblique vein. (05 Mar 2000) |
| tendon sheath of superior oblique muscle | <anatomy> The synovial sheath enclosing the tendon of the superior oblique muscle as it passes through the trochlea. Synonym: vagina tendinis musculi obliqui superioris, synovial trochlear bursa, trochlear synovial bursa, vagina synovialis trochleae. (05 Mar 2000) |
| external oblique | <anatomy, muscle> Origin, fifth to twelfth ribs; insertion, anterior half of lateral lip of iliac crest, inguinal ligament, and anterior layer of the rectus sheath; action, diminishes capacity of abdomen, draws thorax downward; nerve supply, thoracoabdominal nerves. Synonym: musculus obliquus externus abdominis, abdominal external oblique muscle. (05 Mar 2000) |
| external oblique reflex | Contraction of the external oblique and rectus abdominis muscles upon tapping the anterior and outer part of the lower thoracic wall. (05 Mar 2000) |
| external oblique ridge | A horizontal bony crest on the external surface of the body of the mandible, inferior to the alveolar bone, marking the site of attachment of the buccinator muscle. (05 Mar 2000) |
| extinction oblique | <microscopy> Vibration directions oblique to the long direction of the crystal or fibre. (05 Aug 1998) |
| lateral oblique radiograph | A radiographic view of the mandible, revealing one side of the mandible from symphysis to condyle by displacing the other side upwards. (05 Mar 2000) |