The surgical diseases of the ear / by Prof. von Troltsch. The mechanism of the ossicles and the membrana tympani / by Prof. Helmholtz ; translated from the German by James Hinton.

  • Tröltsch, Anton Friedrich, Freiherr von, 1829-1890.
Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: The surgical diseases of the ear / by Prof. von Troltsch. The mechanism of the ossicles and the membrana tympani / by Prof. Helmholtz ; translated from the German by James Hinton. Source: Wellcome Collection.

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

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    ]23 merits of the malleus there is no necessity for much mobility of the tendon. The tensor tympani draws the handle of the malleus and with it the membrane inwards, and so stretches the latter. This action is easily seen in a preparation in winch the canal of the muscle and the tympanum are opened from above. If one takes hold of the tendinous strands of the muscle still within the canal and draws upon them, the membrane is stretched. As the attachment of the muscle lies only a little lower than the axis ligament of the malleus, this is also stretched medianwards, especially its posterior portion (the ligamentum mallei posticum), which most nearly corresponds to the direction of the tensor tympani. A very moderate tension of the tendon gives a very tense poise to the malleus. We must here consider that a slight tension, which is exerted transversely upon a tense inextensible band, is able to increase the tension of that band very considerably, and that the living muscles in their natural state must be considered as very yielding, yet always slightly stretched, elastic bands, which tension becomes very considerably increased by their active contraction. Tor the rest, since the tensor tympani is, on account of its feathered structure,, equivalent mechanically to a muscle of much greater section and less length of fibre, we must regard its elastic strain, even without any active contraction, as a considerable force. In this way it is evident that the malleus, although held only by pliant bands, yet as long as its natural fastenings remain, has, even after disarticulation of the stapes, but a very slight mobility, and this in the way of turning on its axis as above described; and it is also evident that it opposes a very considerable resistance to any attempt to force it in a different direction. Its axis is fastened in front by the ligamentum anterius, and by the processus folianus, which lies in it. Posteriorly it is fastened by the hindermost strands of the ligamentum externus. These two we have classed together as the axis-band of the malleus. This ligament is always somewhat tense, even if the tendon of the tensor tympani is severed; but so long as this muscle exerts its strain transversely upon the axis-band, the tension of the latter is kept at a high point. The malleus thus attached possesses, further, the above-described limiting bands against outward motion of the handle; these are, besides the tendon of the tensor tympani, (i) the central and ante-