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

The shape of the tibia along its length

The tibia, like the fibula, is in some degree triangular in the middle of its length. 47 Its first line [margo anterior] (g, g in figs 1, 3) is situated on the anterior surface of the bone and stands out prominently, for which it is also called the “spine” by professors of anatomy. This extends so sharply that when children are fighting with their feet we see them aim nowhere more often at each other


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than at the anterior surface of the tibia, where the line is closest beneath the skin and cuts it like a knife whenever the skin is battered by a blow to the tibia. The second [margo interosseus] (d, d in figs 1, 2, 3, 4) and third [margo medialis] (e, e in the same figures) lines of the tibia make up the sides 48 of the posterior surface [facies posterior] (q in figs. 2, 4); the third, not sharply formed but quite obtuse and almost rounded, is the inner side of this surface. The second line is a little sharper, and forms the outer side of the posterior surface of the tibia. This is the one to which it was recently said the ligament [membrana interossea cruris] connecting the fibula to the tibia is inserted. The three sides of the tibia are made by these three lines: the first [facies lateralis] (z in figs. 1, 3), bordered by the first and second lines, is depressed and flat, hollowed because of the same muscles [m. tibialis anterior] to which it has been said the first side [facies medialis] of the fibula (x in figs. 1, 5) gives way. The second side [facies medialis] of the tibia (h in figs. 1, 3, x, y in the first table of muscles, q, k in the 2nd), bordered by the first and third lines, is distinctly convex and convered by no muscle at all. It is called kre/a by the Greeks, and more often a)ntiknh/mion. 49 The third side [facies posterior] (q in figs. 2, 4) of the tibia, circumscribed by the second and third lines, is not very much depressed, and is occupied by muscles that claim their place in the posterior surface of the tibia, especially by the one [m. flexor digitorum longus] (C in the 14th table of muscles) which will be called the flexor of the third bone of the four toes, and the one [m. tibialis posterior] (D, E in the 15th table of muscles) which we shall establish as the fifth of the movers of the foot. In addition, this third side shows a rough line [linea musculi solei] (k in figs. 2, 4) in its upper part, extending obliquely, in which a muscle [m. popliteus] (G in the 14th table of muscles) is inserted which we shall call the one hidden in the back of the knee [popliteal fossa]. Such lines and sides of the fibula and tibia easily show how suited these bones are to supporting and producing 50 muscles, while the joints show how ingeniously Nature has constructed these bones for undertaking the motions that we make with our legs, 51 enlarging them near the joints in the way we have stated. No one can contemplate them without the greatest admiration of our Creator, or readily inferring how He would have vitiated their entire structure had He fashioned a construction altered from any of those which we have just now described. 52



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