| 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) |
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| 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 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) |
| tympanic opening of auditory tube | An opening in the anterior part of the tympanic cavity below the canal for the tensor tympani muscle. Synonym: ostium tympanicum tubae auditivae, tympanic opening of eustachian tube. (05 Mar 2000) |
| tympanic opening of canaliculi for chorda tympani | The small canal opening found lateral to the pyramidal eminence in the posterior wall of the middle ear cavity from which the chorda tympani nerve emerges to pass anteriorly between the ossicles accompanied by a branch of the stylomastoid artery. Synonym: apertura tympanica canaliculi chordae tympani. (05 Mar 2000) |