The utero-extemal border

The Utero-extemal

The utero-extemal border commences above in front of the head, runs verti- cally downward to a little below the middle of the bone, and then, curving some­what outward, bifurcates so as to embrace the triangular subcutaneous surface immediately above the outer surface of the external malleolus. This border gives attachment to an intermuscular septum, which separates the extensor muscles on the anterior surface of the leg from the Peroneus longus and brevis muscles on the outer surface. The antero-internal border, or interoBBeous ridge, is situated close to the inner side of the preceding, and runs nearly parallel with it in the upper third of its extent, but diverges from it so as to include a broader space in the lower two-thirds. It commences above, just beneath the head of the bone (sometimes it is quite indistinct for about an inch below the head), and terminates below at the apex of a rough triangular surface immediately above the articular facet of the external malleolus. It serves for the attachment of the interosseous membrane, which sepa­rates the extensor muscles in front from the flexor muscles behind. The postero-extemal border is prominent; it commences above at the base of the styloid process, and terminates below in the posterior border of the outer malleolus. It is directed outward above, backward in the middle of its course, backward and a little inward below, and gives attachment to an aponeurosis which separates the Peronei muscles on the outer surface of the shaft from the flexor muscles on its posterior surface.