A text-book of the diseases of the ear / by Josef Gruber ; translated from the second German edition by special permission of the author, and edited by Edward Law and by Coleman Jewell.

Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: A text-book of the diseases of the ear / by Josef Gruber ; translated from the second German edition by special permission of the author, and edited by Edward Law and by Coleman Jewell. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    before backwards. The curvature from above downwards is scarcely perceptible in its upper two-thirds, but is well marked below on account of the horizontal direction of the lower third of the bone. The squama is therefore divided into an upper, perpendicular, and a lower, horizontal, portion {pat's perpendicularis and pars horizontalis). The zygomatic process (processus zygomaticus—Fig. I, z) springs from the outer surface, close to the junction of the vertical with the horizontal portion, and completes the zygomatic arch by articulating with the malar bone. At the root of the zygomatic process, between two small tuberosi- ties, is seen the fossa glcnoidalis (/), for the condyle of the lower jaw. Fig. i. Squamous portion of the temporal bone seen from without. s, Processus zygomaticus ; /, Fossa glenoi- dalis; v, anterior, h, posterior process of the external plate of the horizontal portion. Fig. 2. Squamous portion of the temporal bone seen from within. P h a i p, Vertical portion; i, internal, a, external plate of the horizontal portion; h, posterior part of the furrow between the two plates of the horizontal part. The upper edge of the zygomatic process passes backwai ds and upwards as a well-marked ridge, which not only assists in the formation of the arcus temporalis, but also indicates the boundary between the perpen- dicular and horizontal portions of the squama. Of the two prominences seen at the root of the zygomatic process, and between which is placed the articular cavity for the condyle of the lower jaw, the anterior lemimentia articularis), even in the infant, is rounded, while the posterior is more angular. The latter merely serves as a limitation of the articular cavity, v.ule t le former plays a most important part in the temporo-maxillary joint ; for the condyle of the jaw passes forward on to this eminence when the mandible is depressed, and glides back into the fossa glenoidalis again when it is raised. The inner or median surface of the squamous portion (Fig. 2) is almost quite smooth in the infant; while in the adult it exhibits depres- sions (imprcssioncs digitated) produced by the cerebral convolutions, which in the child are less prominent than in the adult. In the upper two- thirds of the squama the two lamellae of bone are in close relation to