. The comparative anatomy of the domesticated animals. Veterinary anatomy. THE MIDDLE EAB OB TYMPANUM. 843 3. Os Orbiculare.—This is a little, circular, discoid bone, included between the inferior brancb of the incus and stapes. 4. Stapes (stirrup).—Eemarkable for its shape, which is exactly that of a stirrup, this bone is placed almost horizontally. Its summit (or liead) articulates with the os orbiculare; its middle part is divided into two branches, having between them an aperture that is closed by the tympanic mucous membrane. Its base is received into the fenestra ovalis, and re- sembles
. The comparative anatomy of the domesticated animals. Veterinary anatomy. THE MIDDLE EAB OB TYMPANUM. 843 3. Os Orbiculare.—This is a little, circular, discoid bone, included between the inferior brancb of the incus and stapes. 4. Stapes (stirrup).—Eemarkable for its shape, which is exactly that of a stirrup, this bone is placed almost horizontally. Its summit (or liead) articulates with the os orbiculare; its middle part is divided into two branches, having between them an aperture that is closed by the tympanic mucous membrane. Its base is received into the fenestra ovalis, and re- sembles that cavity in shape; it is maintained in its position by the mucous Fig. BONES OF THE MIDDI4E EAR OP THE HORSE.—From an Unpublished Drawing by Lavocat. M, Malleus; 1, Handle ; 2, Head.—E, Incus; 1, Inferior branch ; 2, Superior branch; 3, Body.—L, Os orbiculare; E*, Stapes ; 1, Summit; 2, 2, Branches ; 3, Base.— Me, Muscle of the stapes; o, Bony nucleus in the terminal tendon. lining of the tympanum, which passes over the stapes, after being reflected around the margin of the fenestra ovalis. (These bones transmit the vibrations of the membrana tympani to the fluid in the labyrinth.) 6. Ligaments of the Auditory Bones.—We need only mention the existence of these here, as they are too small and unimportant to merit a particular description. 6. Muscles of the Auditory Bones.—Four muscles have been de- scribed : three destined to move the malleus, and one for the stapes. But two of these being extremely small, and their muscular character doubtful to many anatomists, we will only notice the internal muscle of the malleus and that of the stapes. a. The internal muscle of the malleus (tensor tympani, muscalus internus mallei).—This is a little elongated fasciculus, lodged in a particular groove in the mastoid portion of the temporal bone, and arises near the superior. Please note that these images are extracted from scanned page images that may have been dig
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectveterinaryanatomy
