. The anatomy and physiology of the human body. Containing the anatomy of the bones, muscles, and joints; and the heart and arteries . articu-lated vvith the OS orbiculare ; the arch of the bone is exactlylike that of the stirrup-iron, but elegantly grooved within, soas to give lightness to the bone. It has a membrane stretchedacross within. The base, answering to that part of the stirrup-iron upon which the foot rests, is not perforated, nor is it of aregular form, but is fiat on one side, corresponding with theforamen ovale. It is this base of the bone which is attachedto the membrane stretc
. The anatomy and physiology of the human body. Containing the anatomy of the bones, muscles, and joints; and the heart and arteries . articu-lated vvith the OS orbiculare ; the arch of the bone is exactlylike that of the stirrup-iron, but elegantly grooved within, soas to give lightness to the bone. It has a membrane stretchedacross within. The base, answering to that part of the stirrup-iron upon which the foot rests, is not perforated, nor is it of aregular form, but is fiat on one side, corresponding with theforamen ovale. It is this base of the bone which is attachedto the membrane stretched over the foramen ovale. CONNECTION AND MOTION OF THESE BONES. The malleus hanging on that part which we have called theneck of the bone, has the long handle or body of the bone • See plate 9. fig. 1. b. f See plate 4. %. 1. b. + See plate 9. fig. 1. c. OF THE HUMAN EAR. 115 Stretched down upon the membrane of the tympanum. It is,consequently, destined to receive the oscillations of that mem-brane. The head of the malleus is so articulated with the incus,that the degree of motion communicated to that bone is T oFtihJiMaXUits *«X , From this scheme, we see, that the head of the malleus isso articulated with the body of the incus, that the centre ofmotion of the incus is in a line drawn through the centre of itsbody, and, consequently, that the extremity of the long pro-cess, to which we see the os orbiculare and stapes attached,moves through a greater space than that which receives theimpulse of the head of the malleus. Thus, a very small de-gree of motion communicated by the head of the malleus tothe body of the incus, must be greatly increased in the ex-tremity of the long process of the incus, and, consequently,this mechanism of the bones essentially assists in giving strengthto the vibration which is transmitted inward to the,seat of thenerve. The OS orbicvdare stands simply as a link of communicationbetwixt the extremity of the incus and the upper
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Keywords: ., bookcentury1800, bookidanatomyphysiolog, booksubjecthumananatomy
