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 fibula is a triangle along its length

If you examine the fibula, you will see that along its longitudinal course it is a triangle, especially close to the middle of its length. In the middle of its anterior surface 43 there appears a sharp and conspicuously protuberant line [margo anterior] (s, s in figs. 1, 5), constituting the first angle of the fibula. On its posterior surface [facies posterior] it is depressed and flat, and on each side at the sides of its posterior surface it displays a single line (the second line [margo interosseus] is marked t, t in figs. 1, 2, 5, 6; the third [margo lateralis] is u, u) which protrudes rather prominently and forms another angle of the fibula. The line that occupies the inner side of the posterior surface of the fibula can be called the second angle of the fibula, and the one that holds the outside if this surface the third. In these three lines or angles are contained the three sides of the fibula (the first [facies medialis] is x in figs. 1, 5; the second [facies lateralis] a in 1, 5; the third [facies posterior] b in 2, 6). One is situated between the first and second angles, providing, in combination with the outer side [facies lateralis] (z in fig. 1) of the tibia, a fit seat for those muscles which are borne from the anterior surface of the tibia to the top of the foot. Those are the sixth [m. tibialis anterior] (Y in the 3rd table of muscles) of the muscles moving the foot, the muscle [m. extensor digitorum longus] extending the four toes (Y in the 4th table on muscles), the ninth [m. fibularis tertius] (W in the 4th table) of those that move the foot, and the one [m. extensor hallucis longus] that extends the big toe (F in the 5th table). The fibula puts forth a separate line [facies medialis] (x, x in figs. 1, 5) that protrudes slightly in this first side from which a beginning is provided for that muscle. The second side is bordered by the first and third line; wide and quite concave, it provides a place for the seventh [m. fibularis longus] (F in the 6th table of muscles) and eighth [m. fibularis brevis] (Y in the 6th table of muscles) muscles moving the foot. For the sake of the eighth muscle, this side is quite rough so that it may have its entire beginning from here in a fine way. The first line or angle of the fibula [margo anterior] is produced by the muscles 44 that occupy the first side [facies medialis] of the fibula and those [m. fibularis longus, m. fibularis brevis] that are extended along the second side [facies lateralis]. The third side [facies posterior], bordered by the second and third lines, 45 is compressed by the muscles occupying the posterior surface of the tibia, and especially by the muscle [m. flexor hallucis longus] (L in the 14th table of muscles) that flexes the second bone of the big toe and is fleshy at its origin from this side of the fibula. Since these things are so, the third line is pushed outward by the muscles occupying the second and third side, while the second line is produced by the muscles which compress the third and first sides of the fibula. 46 But this second line separately puts forth a ligament [membrana interossea cruris] (a in the figure for ch. 1, Bk. 2) binding the fibula to the tibia along the entire area where these bones separate; it is inserted into the second line [margo interosseus] (d, d in figs. 1, 2) of the tibia.



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