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A passage or channel, especially the external opening of a canal. SYN: external opening. [L. a going, a passage, fr. meo, pp. m., to go, pass]
- external acoustic m. [TA] the passage leading inward through the tympanic portion of the temporal bone, from the auricle to the tympanic membrane; it consists of a bony (inner) portion and a fibrocartilaginous (outer) portion, the cartilaginous external acoustic m.. SYN: m. acusticus externus [TA], acoustic m., antrum auris, auditory canal, ear canal, external auditory m..
- fish-mouth m. a red and swollen condition of the orifice of the urethra (urinary m.) in gonorrhea.
- internal acoustic m. [TA] a canal beginning at the opening of the internal acoustic m. in the posterior cranial fossa, passing laterally through the petrous portion of the temporal bone to end at the fundus, where a thin plate of bone separates it from the vestibule; it gives passage to the facial and vestibulocochlear nerves together with the labyrinthine artery and veins. SYN: m. acusticus internus [TA], internal auditory m..
- nasal m. [TA] any of four passages in the nasal cavity formed by the projection of the conchae: inferior nasal m. [TA] (m. nasi inferior [TA]), lies below the inferior concha; middle nasal m. [TA] (m. nasi medius [TA]), lies between the middle and inferior conchae; superior nasal m. [TA] (m. nasi superior [TA]), lies between the superior and middle conchae; common nasal m. [TA] (m. nasi communis [TA]) is the part of the nasal cavity between the conchae and the nasal septum. SYN: m. nasi [TA].
- m. nasi [TA] SYN: nasal m..
- nasopharyngeal m. [TA] the posterior part of the nasal cavity from the posterior limits of the conchae to the choanae. SYN: m. nasopharyngeus [TA], nasopharyngeal passage.
- m. nasopharyngeus [TA] SYN: nasopharyngeal m..
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me·atus mē-'āt-əs n, pl me·atus·es -ə-səz or me·atus -'āt-əs, -'ā-.tüs a natural body passage: CANAL, DUCT
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n.
(in anatomy) a passage or opening. The auditory meatus is the passage leading from the pinna of the outer ear to the eardrum. A nasal meatus is one of three groovelike parts of the nasal cavity beneath each of the nasal conchae. The urethral meatus is the external opening of the urethra.
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me·a·tus (me-aґtəs) pl. meaґtus [L., “a way, path, courseâ€] a passageway in the body, especially one opening on the surface. meatal adjMedical dictionary. 2011.