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 6 On the Eight Bones of the Head and the Sutures Connecting Them

The thickest point of the occiput

Nor is the bone of the occiput of equal thickness throughout its unfleshed surface; at its root it looks much the thickest in the middle [protuberantia occipitalis interna] (k in figure 6), in the region (R in figure 7, Book 7) where — as you will hear in the account of the vessels of the brain — the two greatest sinuses [sinus sagittalis superior et sinus rectus] of the hard membrane [dura mater] of the skull, containing blood and vital spirit in the manner of veins and arteries, are joined [confluens sinum], and put forth two other sinuses [sinus transversus]. For Nature seems to have provided for this meeting of sinuses [confluens sinum] by the thickness of the bone, both because a wound here could be extremely dangerous to a person, and also because she was not unaware that this part of the occiput, having no eyes, would be constantly exposed to blows, and likely frequently to be dashed against the ground in various falls. This thickest part of the occipital bone, like all the unfleshed part of this bone, is made of little cavities [diploë] inside that are covered on both sides with a strong plate [lamina externa et interna], just as we have reported the vertex and the frontal bone are constructed in their unfleshed portions (these are found in fig. 6 but more clearly shown in fig. 9, Bk. 7). The remaining surface of the occipital bone, where some of the muscles 102 occupying the back of the neck are inserted, and from which some take their origin,


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is seen to be solid and rather dense but exceedingly thin, and without pores. This is the place that the cerebellum fills. To avoid negligenge of the bone’s strength because of its unusual thinness, a long, linear tubercule [crista occipitalis interna] (from k to the foramen [foramen magnum] marked e in fig. 6) projects in the middle, greatly increasing the bone’s strength in that area. Further, because this tubercule projects into the inner space of the skull, it forms two depressions [fossae cerebellares], one on each side, which the cerebellum fills. This tubercule, like the thin part of the occipital bone, extends from the base [protuberantia occipitalis interna] of the unfleshed part of the occipital bone to the posterior region of the foramen [foramen magnum] made for the dorsal medulla. From the anterior part [clivus] (from e to P in figure 6) of the foramen transmitting the dorsal medulla, and where the occiput is narrowst, it thickens gradually so that it appears quite thick where it joins the cuneiform bone.



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 6 On the Eight Bones of the Head and the Sutures Connecting Them