| oesophageal opening | The opening in the right crus of the diaphragm, between the central tendon and the hiatus aorticus, through which pass the oesophagus and the two vagus nerves. Synonym: hiatus oesophageus, oesophageal opening. (05 Mar 2000) |
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| opening | 1. The act or process of opening; a beginning; commencement; first appearance; as, the opening of a speech. "The opening of your glory was like that of light." (Dryden) 2. A place which is open; a breach; an aperture; a gap; cleft, or hole. "We saw him at the opening of his tent." (Shak) 3. Hence: A vacant place; an opportunity; as, an opening for business. 4. A thinly wooded space, without undergrowth, in the midst of a forest; as, oak openings. Source: Websters Dictionary (01 Mar 1998) |
| opening axis | An imaginary line around which the mandibular condyles may rotate during opening and closing movements. Compare: fulcrum line. (05 Mar 2000) |
| opening contraction | A contraction produced at the time of opening the circuit when using direct current to stimulate the muscle or a motor nerve. (05 Mar 2000) |
| opening movement | In dentistry, movement of the mandible executed during jaw separation. (05 Mar 2000) |
| opening of external acoustic meatus | The orifice of the external acoustic meatus in the tympanic portion of the temporal bone. Synonym: porus acusticus externus, external acoustic foramen, external acoustic pore, external auditory pore, external auditory foramen, orifice of external acoustic meatus. (05 Mar 2000) |
| opening of inferior vena cava | The orifice through which the inferior vena cava opens into the right atrium. Synonym: ostium venae cavae inferioris, orifice of inferior vena cava. (05 Mar 2000) |
| opening of internal acoustic meatus | The inner opening of the internal acoustic meatus on the posterior surface of the petrous part of the temporal bone. Synonym: porus acusticus internus, internal acoustic foramen, internal acoustic pore, auditory pore, internal auditory foramen, orifice of internal acoustic meatus. (05 Mar 2000) |
| opening of pulmonary trunk | The opening of the pulmonary trunk from the right ventricle, guarded by the pulmonary valve. Synonym: ostium trunci pulmonalis, pulmonary orifice. (05 Mar 2000) |
| opening of superior vena cava | The point of entry of the superior vena cava into the right atrium. Synonym: ostium venae cavae superioris, orifice of superior vena cava. (05 Mar 2000) |
| opening of the sphenoidal sinus | One of the pair of openings in the body of the sphenoid bone through which the sphenoid sinuses communicate with the sphenoethmoidal recess of the nasal cavity. Synonym: apertura sinus sphenoidalis, sphenoidal sinus aperture. (05 Mar 2000) |
| opening of uterus | The vaginal opening of the uterus. Synonym: ostium uteri, mouth of the womb, opening of uterus, orificium externum uteri, os uteri externum, ostium uteri externum. (05 Mar 2000) |
| opening to cerebral aqueduct | Entrance to the cerebral aqueduct (of Sylvius) from the caudal part of the third ventricle. Synonym: aditus ad aqueductum cerebri, Bartholin's anus, opening to cerebral aqueduct. (05 Mar 2000) |
| orbital opening | The somewhat quadrangular anterior entrance to the orbit which forms the base of the pyramid-shaped orbital cavity. It is bounded by the sharp supra-, infra-, and lateral orbital margins and a less obvious medial margin on each side of the upper nose. Synonym: aditus orbitae, aperture of orbit. (05 Mar 2000) |
| tendinous opening | The aperture in the aponeurotic insertion of the adductor magnus that transmits the femoral artery and vein from the adductor canal to the popliteal space. Synonym: hiatus tendineus, hiatus adductorius, femoral opening, tendinous opening. (05 Mar 2000) |