\ 



1464 CLINICAL AND TOPOGRAPHICAL ANATOMY 



(C) Anterior annular ligament. — This is a double structure. (1) Upper 

 (transverse crural ligament), above the level of the ankle-joint, and tying the 

 tendons down to the lower third of the leg, passes transversely between the ante- 

 rior crest of the tibia and fibula. Here is one sheath only, with a synovial mem- 

 brane for the tibialis anterior. (2) Lower, over the ankle-joint. This band, the 

 cruciate ligament, is arranged like the letter -<, placed thus. It is attached by its 

 root to the calcaneus, and by its bifurcations to the medial malleolus and plantar 

 fascia. 



This arrangement of the branches of this ligament is not constant. In this, the lower 

 annular ligament, there are usually three sheaths with separate synovial membranes — the 

 most medial (the strongest in each) for the tibialis anterior, the next for the extensor hallucis 

 longus, and the third common to the extensor communis and peroneus tertius. The extensor 

 digitorum brevis has a partial origin from this ligament. 



Points in tenotomy and guides to the tendons. — The tendo Achillis should be divided 

 about 3.7 cm. (1| in.) above its insertion, its narrowest point, which is about on a level with the 

 medial malleolus. The knife should be introduced on the medial side and close to the tendon, 

 so as to avoid the posterior tibial artery (fig. 1178). 



The tibialis anterior may be divided about 25 mm. (1 in.) above its insertion into the first 

 cuneiform, a point which is below the level of its synovial sheath. The tendon has here the 

 dorsalis pedis on its lateral side, but separated by the tendon of the extensor haUucis longus. 

 The knife is introduced on this side. 



The tibialis posterior. — The usual rule for dividing this tendon is to take a spot 5 cm. 

 (2 in.) above the medial malleolus, and as accurately as possible midway between the anterior 

 and medial borders of the leg. This point will give the medial margin of the tibia, in close ap- 

 position to which the tendon is lying, and is a point at which the tendon is rather farther from 

 the artery than it is below, and is also above the commencement of its synovial sheath. A 

 sharp-pointed knife is used first to open the sheath freely, and then a blunt-pointed one to 

 divide the tendon. The flexor digitorum longus is usually cut at the same time. 



Owing to the risk of injury to the posterior tibial vessels, the difficulty of ensuring division 

 of the tendons, the following open method is, nowadays, superior, being more certain, and ad- 

 mitting of division of ligaments, e. g., talo-navicular and anterior part of deltoid (syndesmotomy 

 of Parker), which are always contracted in advanced talipes equino-varus. A V-shaped flap 

 with its apex over the first metatarsal bone and its two limbs starting, the lower below the 

 margin of the plantar fascia on a Une with the medial malleolus, the upper from a point over 

 the head of the talus, is turned backward. The plantar fascia is divided, the tibialis anterior is 

 found, near its insertion, under the upper lip of the wound, the tibialis posterior and the flexor 

 digitorum longus in the lower, the former close to the navicular. If necessary, the calcaneo- 

 and talo-navicular and anterior part of the deltoid ligaments can be divided also. 



Peronei. — The peronei longus and brevis may be divided 5 cm. (2 in.) above the lateral 

 malleolus, so as to be above the level of their synovial sheath. The knife should be inserted 

 very close to the bone, so as to pass between the fibula and the tendons. Division below the 

 ateral malleolus by a small flap is easier. 



THE FOOT 



Bony landmarks. — The following are of the greatest practical importance 

 owing to the operations which are performed upon the foot. 



(A) Along the medial aspect of the foot are the following : — 



(1) Medial tuberosity of the calcaneus; (2) medial malleolus; (3) 2.5 cm. 

 (1 in.) below the malleolus, the sustentaculum tali; (4) about 2.5 cm. (1 in.) in 

 front of the medial malleolus, and a little lower, is the tuberosity of the navicular, 

 the medial guide in Chopart's amputation, the gap between it and the susten- 

 taculum being filled })y the calcaneo-navicular ligament and the tendon of the 

 til)ialis posterior, in which there is often a sesamoid bone; (5) the first cuneiform; 

 (6) the base of the first metatarsal; and (7) the head of the same bone, with its 

 sesamoid l)ones h)elow. (Holden). 



(B) Along the lateral aspect are :■ — (1) The lateral tuberosity of the calcaneus; 

 (2) the lateral malleolus; (3) the peroneal tubercle of the calcaneus (when pres- 

 ent), 2.5 cm. (1 in.) below the malleolus, with the long peroneal tendon below it, 

 and the short one al)ove; (4) the projection of the anterior end of the calcaneus, 

 and the caleaneo-cuboid joint, midway between the tip of the lateral malleolus and 

 the base of the fifth metatarsal bone; (5) the base of the fifth metatarsal bone; (6) 

 the head of this bone. The greater process of the calcaneus and the muscular 

 origin of the short extensor lie between the peroneus brevis and tertius. • 



Levels of joints and lines of operations. -'I'ho line of the ankle-joint has been given at 

 p. 14.')f>. That of fh(! talo-calfuncal joint —the limited lateral movements of the foot take 

 place here and at the medio-tarsal joint — corresponds, on the lateral side, to a point a little in 

 front of the lateral malleolus and midway between it and the peroneal tubercle; on the medial 



