. Anatomy, descriptive and applied. Anatomy. THE MIDDLE EAR, DRUM, OR TYMPANUM consists of two strata—an external, of radiating fibres (sfrafiim rndiatiim), whirh diverge from the handle of the malleus, and an internal, of circular fibres {xlralmii rin'iilarr), which are plenti- ful around the circumference, but sparse and scattei'cd ncai' the centre of the membrane. Branched i>r dendritic fibres, as pointed out by Grliber, are also present, especially in the pos- terior half (if the iiiciiiKi-ane. The arteries arc ilcriwd from the deep auricular branch of the internal maxillary, whic
. Anatomy, descriptive and applied. Anatomy. THE MIDDLE EAR, DRUM, OR TYMPANUM consists of two strata—an external, of radiating fibres (sfrafiim rndiatiim), whirh diverge from the handle of the malleus, and an internal, of circular fibres {xlralmii rin'iilarr), which are plenti- ful around the circumference, but sparse and scattei'cd ncai' the centre of the membrane. Branched i>r dendritic fibres, as pointed out by Grliber, are also present, especially in the pos- terior half (if the iiiciiiKi-ane. The arteries arc ilcriwd from the deep auricular branch of the internal maxillary, which ramifies beneath the cuticular layer and from the stylomastoid branch of the posterior auricular and tympanic branch of the internal maxillary, which are distributed on the mucous surface. The arteries of the cutaneous set anastomose with the arteries of the mucous set by minute branches which penetrate the drum membrane near its margin. The superficial veins open into the external jugular; those on the mucous surface drain partly into the lateral sinus and veins of the dura and partly into a plexus on the Eustachian tube. The outer surface of the drum membrane receives its nerve supply from the auriculotemporal branch of the inferior maxillary and the auricular branch of the vagus. The inner surface is supplied by the tym- panic branch of the glossopharyngeal. There are two sets of lymphatics, the cutaneous and mucous, which freely communicate. Tht spaces between the dendritic fibres of Grliber are lymph spaces (Kessel). The Ossicles of the Tympanum (ossicida aiditus) (Fig, 849).—The tym- panum contains in its upper part a chain of movable bones, three in number, the malleus, incus, and stapes. The first is attached to the membrana tympani, the last to the fenestra ovalis, the incus being placed between the two, and connected to both by delicate articulations. The Malleus (Fig. 850), so named from its fancied resemblance to a hammer, is placed farthest in front and outwa
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1913
