Politzer's text-book of the diseases of the ear and adjacent organs... / by Adam Politzer ; translated by Oscar Dodd ; edited by Sir William Dalby.

  • Politzer, Adam, 1835-1920.
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: Politzer's text-book of the diseases of the ear and adjacent organs... / by Adam Politzer ; translated by Oscar Dodd ; edited by Sir William Dalby. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    tympanum. It is penetrated by bloodvessels which are inconstant in their com*se and anastomosis. The membrana tAmpani possesses two vascular networks, separated by the substantia propria, and anastomosing with each other at the periphery, the outer one belonging to the connective tissue of the cutis, the inner to the mucous membrane. The vascular network of the cutis comes from the arteria auricularis profunda, which sends a branch to the centre of the membrana tympani. This branch lies between two venous branches, which form a plexus here and there, and descends to the umbo from the superior posterior wall of the meatus, behind the handle of the malleus. These vessels do not lie immediately behind the handle, but at some distance from it, in such a way that between them and the bone a portion of the membrana tympani is visible, its point directed downwards. At the centre of the membrane the arteries as well as the veins c ommunicate by numerous radiating branches with a vascular zone, situated at the periphery of the membrane, and through this also with the vessels of the tympanic cavity (Moos, Arcliiv, f. Augen. und OhrcnheiVk., vol. vii.). According to Moos, anastomosing bloodvessels perforate the membrana t.Mnpani in the region of the hammer and at other places. According to the investigations of Prussak, the veins are in greatest nmnbers at the handle of the malleus, as well as at the periphery. The arterial branches which run along the handle of the malleus, partly enter at once into the venous plexus in the neighbourhood, and partly pass across the membrana tympani to the marginal venous zone. Burnett foimd vascular loops always present on the membrana tj'mpani of the ox, the cat, and the goat. The veins of the cutaneous layer of the membrana timpani are connected partly with the veins in the external meatus, partly, on the periphery of the membrana t^anpani, vnih. the vessels in the tympanic ca\'ity through apertures sometimes of considerable size. The vascvdar network on the siu-face of the lining membrane springs from the vessels of the tympanic cavity, and presents a rather closely ineshed capillary system, developed from an artery which runs parallel to the handle of the malleus, on the inner side of the membrana tjmpani (Moos). The lymphatic vessels of the membrane, according to Kessel {Handbuch der Lehre von den Gewehen, 1870), are, like the bloodvessels, arranged in three layers anastomosing vsdth each other. If the epithelium of the lining membrane be brushed off, with a low microscopic power, a fibrous framework (designated by Gruber dentritic formation) vnll be found lying upon the substantia propria, which is often spread over the whole membrane, but is especially developed on that part situated behind the handle of the malleus. From the membranous expansion of this fibrous framework, which is inter- rupted here and there (Fig. 21, a) by large and small interspaces, there radiate towards the handle of the malleus, as well as towards the peripheral tendinous ring, processes which form curves of different sizes. These processes strike deep and amalgamate with the fibres of the substantia propria. According to my own investigation a similar formation is to be found in the mucous membrane of the cavum tympani, and consequently it cannot be considered a structural peculiarity of the membrana tympani.