1194 SURGICAL AXD TOPOGRAPHICAL AXATOMY 



the tibialis posticus, its nerve being to the outer side. The peroneal would be close 

 to the fibula in the flexor longus hallucis. 



The musculo-cutaneous nerve, having, passed through the peroneus longus, 

 and then between the peroneus longus and peroneus brevis, perforates the deep 

 fascia in the lower third of the leg in the line of the se])tum between the peronei 

 and extensors. Directly after, it divides into its two terminal branches. 



THE ANKLE 



Bony landmarks. — Malleoli. — The following are the differences between 

 them: The internal is the more prominent, shorter, and is placed more anteriorly 

 than the outer, being a little in front of the centre of the joint. The external 

 descends lower by a half to three-quarters of an inch, and thus securely locks in 

 the joint on this side; it is opposite to the centre of the ankle-joint, being placed 

 abovit half an inch behind its fellow. Owing, however, to the greater width of the 

 internal malleolus, its posterior border is on a level with that of its fellow. The 

 anterior margin of the lower end of the tiljia can be traced above the ankle-joint, 

 crossed l^y the tendons given Ijelow. Owing to the external malleolus descending 

 lower than the inner, in Syme's and Pirogoff's amputations the incision should run 

 between the tip of the external malleolus and a point half an inch below that of 

 the internal one. When a fracture is set, or a dislocation adjusted, the inner edge 

 of the patella, the internal malleolus, and the inner side of the great toe are useful 

 landmarks and should be in the same vertical plane, regard being paid at the same 

 time to the corresponding points in the opposite limb (Hold en). 



Tendons. — (A) In front of ankle. — From Avithout inwards are — (1) The 

 tibialis anticus, the largest and most internal. This tendon appears in the lower 

 third of the leg, lying just under the deep fascia, close to the tibia; then, crossing 

 over the lower end of this and the ankle-joint, it passes over the inner side of the 

 tarsus, to be attached to the inner and lower part of the internal cuneiform and the 

 adjacent part of the first metatarsal. (2) The extensor proprius hallucis. This 

 tendon, concealed above, appears low down in a line just external to the last, and 

 then, crossing over the termination of the anterior tibial vessels and nerves (to 

 which its muscular part lies external), it descends along the inner part of the 

 dorsum to l)e attached to the base of the last phalanx of the great toe. (3) and 

 (4) The extensor longus digitorum and peroneus tertius enter a common sheath in 

 the anterior annular ligament. The former then divides into four tendons, which, 

 joined on the first phalanx by slips, three from the extensor brevis, and, a little 

 later, by slips from the lumbricales and interossei, are inserted into the second and 

 last phalanges, as in the fingers. The peroneus tertius is inserted into the up^jer 

 surface of the base of the fifth metatarsal bone. 



(B) Behind. — The tendo Achillis, the thickest of all tendons, begins near the 

 middle of the leg, in the junction of the tendons of the gastrocnemii and soleus. 

 Very broad at its commencement, it gradually narrows and becomes very thick. 

 About an inch and a half from the heel, or about the level of the internal 

 malleolus, is its narrowest point. After this it again expands slightly, to be 

 attached to the middle of the back part of the calcaneum. The long tendon of the 

 plantaris runs along its inner side, to l)lcnd with it or to be attached to the calca- 

 neum. On either side of the tendo Achillis are well-marked furrows beloAv. Along 

 the inner, the tendon of the tibialis posticus and the posterior tibial vessels and 

 nerve come nearer the surface. Along the outer, the external saphenous vein 

 (more superficially) ascends from behind the external malleolus. 



(C) On the inner side. — The tendon of the tibialis posticus, which has 

 previously crossed from the interspace between the bones of the leg to the inner 

 side, lies behind the inner edge of the tibia above the internal malleolus, being 

 under the flexor longus digitorum, the two tendons here becoming su])erlicial on 

 the inner side of the tendo Achillis. It then passes forwards close below the sus- 

 tentaculum tali and the head of the astragalus, and then very close to the inferior 

 calcaneo-scaphoid ligament (vide infra), and so to its insertion, by numerous slips, 

 into the tarsus and metatarsus, especially the tubercle of the scaphoid. The tendon 



