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 31 On the Tibia and Fibula

Cartilages by which the socket of the tibia is enlarged

Since the two depressions of the tibia that admit the heads of the femur are carved only more or less superficially and do not exactly match the projecting femoral heads with their hollows (even though it seemed otherwise to Galen), 19 Nature augmented the depth of the depressions with a marvellous artifice. In addition to the slippery cartilages [cartilago articularis] covering the depressions of the tibia and the heads of the femur like a coating, she added to each depression a single cartilage [meniscus], unconnected to the femur or the tibia by any means except by ligaments. 20 This cartilage is attached only to ligaments that embrace the knee joint in a circle; it is also connected by a ligament to the anterior and posterior ends of the eminence [emin. intercondylaris] which it has been said separates the depressions [facies articularis superior] of the tibia that receive the heads of the femur. These cartilages [menisci] are softer than altogether simple cartilage and participate, as it were, in the nature of ligament. 21 Where they rest upon the bones, they are quite even, slippery, smooth, and coated with an oily humor [synovia]. They are thick on the circumference of the joint (N in fig. 8), becoming much thinner


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and leaving off (O in fig. 8) before reaching the center of the depressions. Their shape is lunar, as is the inner side of the inner depression and the outside of the outer depression. They are nowhere wider than at the middle of their side, and they are narrowest where they approach the anterior and posterior parts (P, P in fig. 8) of the eminence separating the depressions of the tibia and end in sharp points. The points attached to the anterior end of this eminence are close together and the right cartilage is connected to the left there. 22 The ones that come close to the posterior end of the eminence are farther apart and are not joined together like the anterior points of the cartilages because the extremely thick ligament [lig. cruciatum posterius] from the eminence [tibia, eminentia intercondylaris] that is inserted into the femur [femur, condylus medialis] separates the posterior points of the cartilages. These things being so, it is easily inferred how harmoniously the cavity formed by the depressions of the tibia is enlarged with the aid of these cartilages not only in humans, but also in all the quadrupeds and birds that I have so far seen. Cartilages of this kind are situated in their knee joint; there is every opportunity to inspect the nature of any of them at table if one examines the knee joint closely, and has not supposed, with Aristotle and with Galen in the third Book of De usu partium, 23 that the knee of quadrupeds is situated where the lower part [distalis] of the tibia is attached to the talus.



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 31 On the Tibia and Fibula