. Diseases of the ear; a text-book for practitioners and students of medicine. tory or tympanic, and the stylomas-toid. This last center of ossification does not concern us, butthe other three are of importance, as they are all integral partsof the auditory apparatus, and, with the exception of the pe-trous portion, all enter into the formation of the externalmeatus. The manner in which these various portion uniteto form the temporal bone is shown in Fig. 5, which is some-what diagrammatic. The osseous meatus does not exist at birth, its place beingsupplied by a canal of fibrous tissue. Refere
. Diseases of the ear; a text-book for practitioners and students of medicine. tory or tympanic, and the stylomas-toid. This last center of ossification does not concern us, butthe other three are of importance, as they are all integral partsof the auditory apparatus, and, with the exception of the pe-trous portion, all enter into the formation of the externalmeatus. The manner in which these various portion uniteto form the temporal bone is shown in Fig. 5, which is some-what diagrammatic. The osseous meatus does not exist at birth, its place beingsupplied by a canal of fibrous tissue. Reference to Figs. 8,9, and 10, drawn from specimens prepared by the author,renders this clear. At its inner extremity this terminates in Fig. 4. ?a, a, The incisures of Santorini.(Urbantschitsch.) 8 THE ANATOMY AND PHYSIOLOGY OF THE EAR. the auditory process or the tympanic ring. The auditoryprocess Figs. 5 ~_2~_ and 13 [IIIj consist of a thin osseous stripbent in the form of an oval, the curvilinear outline beingwanting- for about an eighth of its circumference at the broader. ~IG. 5.—The development of the temporal bone. I, The squamous portion-. 2,The tympanic ring : 5. The perro-mastoid portion. The upper figure illustratesthe union of the three portions. (Modified from Gray pole. The concave margin of this bonv ring is grooved forthe insertion of the membrana tvmpani. and is named thesulcus tympanicus. while the ring itself is called the annulustvmpanicus. The free extremity of the posterior limb of theannulus is called the spina tvmpanica posterior or spina tym-panies minor. Just below the extremity of the anterior limba bonv spine projects backward, the spina tvmpanica spina tvmpanica anterior is directed forward, and con-sists of a small bony tubercle lying just beneath the largertvmpanic spine. THE BONY MEATUS. The squamous portion of the temporal bone developsfrom a single center. Early in foetal life it consists of a flatosseous scale, presenting a ridge upon
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