Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them] | Chapter 8 On the Ossicles That Enter Upon the Construction of the Organ of Hearing

The anvil-like ossicle [incus]

At the outside of this circle enclosed by the nerve of the fifth pair and nearest the ear [auris externa], an ossicle (I, N, O) is seen that is affixed to this bony circle by two thin, sharp processes like legs [crus longum, crus breve]; above, where its legs meet, it is made thicker and heavier, like an anvil. 4 This is the second ossicle of the organ of hearing, which I am accustomed to show during dissection with considerably less difficulty than I can describe it here,


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so as to be understood by someone who has never seen it. 5 I am unable to add anything to my account by which it may be more clearly recognized, since its shape and location cannot be more clearly explained. As I was saying, this ossicle is located near the outer side of the circle [anulus tympanicus] that is visible in the cavity of the temporal bone when it is broken open, and it puts out two legs by which it is secured, of which the outer leg [crus breve], nearer the ear [meatus acusticus externus], is shorter, thicker, and broader and ends in a sharp point. 6 The other, inner, leg [crus longum] is more attached than the outer leg to the membrane that covers the spherical area of the cavity; it looks thin and a little longer, and it ends in a kind of hook [processus lenticularis] by which it is attached to the membrane [tunica mucosa cavitatis tympanicae] covering the cavity of the temporal bone and firmly implanted. The portion of this bone that projects beyond the membrane appears partly flat on top, partly round, just as small anvils are usually made with the larger part flat and the other ending in a kind of point, rounded like a cone. Larger anvils are completely level, flat, and rectangular. If it is displeasing to compare this ossicle to an anvil because it has only two legs, there is certainly no objection to comparing it to a molar (C in ch. 11 illustrates such a tooth) with two roots.



Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them] | Chapter 8 On the Ossicles That Enter Upon the Construction of the Organ of Hearing