THE ANKLE 1459 



is not well defined, the fascia must be freely slit up in the line of the artery, and the sulcus felt 

 for. A small muscular artery maj' lead down to the trunk. The foot is now dorsiflexed and the 

 artery sought for deep on the interosseous membrane. The nerve should be drawn to the 

 outer side. The vense comitantes may be included in the ligature. 



In senile gangrene the liability of the tibial arteries to disease and consequent thrombosis 

 and interference with the collateral circulation accounts both for the extension of the disease 

 and the difficulty in detecting pulsation. 



The peroneal artery, given off from the posterior tibial about an inch below 

 the popliteus, or two inches below the head of the fibula, runs deeply along the 

 medial border of this bone, covered by the flexor hallucis longus, the nerve to 

 which accompanies the vessel. 



It gives off the anterior peroneal, through the interosseous membrane, to the front of the 

 lateral malleolus about an inch above the level of the ankle-joint. Its continuation, as the pos- 

 terior peroneal, runs behind the malleolus, to join the anastomosis about the ankle-joint. 



The nutrient artery of the tibia arises from the posterior tibial near its commencement. It 

 is the largest of all the nutrient arteries to the shafts of long bones; that for the fibula comes from 

 the peroneal. 



As a general rule, in amputation 2.5 cm. (1 in.) below the head of the fibula, only one main 

 artery — the popliteal — is divided. In amputations 5 cm. (2 in.) below the head of the fibula, 

 two main arteries — the anterior and posterior tibials — are divided. In amputations 7.5 cm. 

 (3 in.) below the head, three main arteries — the two tibials and the peroneal — are divided. 

 (Holden.) 



In an amputation through the middle of the leg, the anterior tibial artery would be found 

 cut on the interosseous membrane between the tibialis anterior and the extensor hallucis longus, 

 the deep peroneal nerve here lying in front of the vessel. The posterior tibial would be between 

 the superficial and deep muscles at the back of the leg lying on the tibialis posterior, its nerve 

 being to the lateral side. The peroneal would be close to the fibula in the flexor haUucis longus. 



The superficial peroneal (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 septum 

 between the peronei and extensors. Directly after, it divides into its two terminal 

 branches. 



Amputation of the leg. — ^To give one instance only, amputation 'at the seat of election, 

 or a hand's-breadth below the knee-joint, will be alluded to. Lateral skin-flaps and circular 

 division of the muscles give an excellent result in hospita' practice where the various conditions 

 which call for such a step are usually met with. The above name was given because the pressure 

 of the body is well carried on the prominences about the knee-joint, especially the tuberosity 

 of the tibia, when the patient walks with the knee flexed on a 'bucket' artificial limb. Thus the 

 scar, being central, is here not of importance. Two broadly oval lateral flaps of skin and fasciae 

 are raised, and the remaining soft parts severed down to the bones with circular sweeps of the 

 knife. In sawing the bone, the smaller size of the fibula and its position behind the tibia must 

 be remembered. It is well, in order to ensure complete division of the fibula first, to roll the 

 limb well over on its medial side, and place the saw well down on the lateral side. The parts 

 cut through are shown in fig. 1174. 



THE ANIvLE 



Bony landmarks. — The following are the differences between the two malleoli : 

 The medial is the more prominent, shorter, and is placed more anteriorly than the 

 lateral, being a little in front of the centre of the joint. The lateral descends 

 lower by about 1.2 cm. (| in.), and thus securely locks in the joint on this side; 

 it is opposite to the centre of the ankle-joint, being placed about 1.2 cm. (| in.) 

 behind its fellow. 



Owing to the lateral malleolus descending lower than the medial, in Syme's and Pirogoff's 

 amputations the plantar incision should run between the tip of the lateral malleolus and a point 

 1.2 cm. (i in.) below that of the medial one. When a fracture is set, or a dislocation adjusted, 

 the medial edge of the patella, the medial malleolus, and the medial 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. (Holden.) 



On the posterior aspect of the medial malleolus is a groove for the tibialis pos- 

 terior and flexor digitorum longus, the first named being next the bone. The tip 

 and borders of the process give attachment to the deltoid ligament. The anterior 

 border and tip of the lateral malleolus give attachment to the anterior talo-fibular 

 and calcaneo-fibular ligaments respectively, the posterior talo-fibular arising from 

 a pit behind and below the articular facet. The posterior border is grooved for 

 the two peronei. The line of the ankle-joint corresponds to one about 1.2 cm. 

 (I in.) below the tip of the medial malleolus drawn across the anterior aspect. 



