150 REGION OF THE ANKLE. 



a deep groove, in which two important tendons from their liability to injury and disease, become 

 are contained, those, namely, of the peroneus of great interest. Upon the instep the course 

 longus and brevis. They are lodged in a canal and relations of the anterior tibiuL artery de- 

 which we have already described as formed by mand particular attention ; the vessel here 

 the bone and the external annular ligament, does not run exactly in the median line of the 

 and this canal is lined by a distinct synovia! foot, but is somewhat nearer to the inner than 

 membrane reflected upon it from the tendons, to the outer malleolus : we may always reach 

 Having passed over the ligaments of the outer it with perfect certainty, by cutting between the 

 ankle, the peronei tendons are next applied tendon of the extensor digitorum longus, and 

 upon the surface of the os calcis; and here, that of the extensor pollicis ; these overlap it 

 though previously in close apposition, and in- upon either side, and afford considerable protec- 

 deed contained within the same synovial sheath, tion against wounds or other injuries. Not- 

 they become separated by a ridge projecting withstanding the facility of reaching the vessel 

 from the bone. The peroneus longus tendon plays in this situation, it is by no means advisable to 

 behind it as upon a pulley, and instances have do so when it is at all possible to avoid it, inas- 

 occurred, where, owing to the fracture of this much as to expose the artery here it is necessary 

 little osseous septum, the peroneus longus has to wound the synovial sheaths, and inflammation 

 been dislocated forwards upon that of the and adhesionwould be the probable consequence 

 brevis. It has also happened that both peronei of such an injury. The branches of the in- 

 tendons have been dislocated forwards from ternal malleolar artery are found upon the 

 their groove behind the malleolus, and thrown inn^r part of the region, running upon and in 

 in front of that eminence. Were such an acci- front of the inner ankle, and anastomosing with 

 dent left without surgical interference, it is inte- others passing forwards from the posterior 

 resting to reflect how completely altered would tibial, thus insuring a sufficient supply ofblood 

 be the action of these two muscles, if that action to the joint, even when the trunk of the anterior 

 were not completely suspended by the inflam- tibial itself has been tied. But these vessels 

 mation and obliteration of the synovial sheath are of much inferior importance compared with 

 consequent on the accident ; instead of extend- the posterior tibial, whose main trunk lies in 

 ing the foot and pointing the toe, as they do in the fossa between the heel and the malleolus 

 their natural state, they would become con- internus. It is here occasionally the subject of 

 verted into flexors and abductors of the foot, operation, and hence its course and relations 

 At the posterior part of the region, the tendo should be very carefully noted. We have al- 

 Achillis forms a remarkable projection. In our ready enumerated the tendons passing beneath 

 account of the fascia, we have described the the annular ligament in this situation ; the most 

 sheath within which this tendon is contained, anterior is that of the tibialis posticus, imme- 

 We may further observe that this tendon is diately behind it lies that of the flexor digi- 

 separated from the joint, and also from the torum, and still more posteriorly, at the interval 

 deep vessels and nerves of the leg, by a consi- of about an inch, is found the tendon of the 

 derable interval, so that it has frequently befen flexor pollicis ; in this interval between the two 

 cut across without injury to the articulation\>r latter tendons runs the posterior tibial artery, 

 wound of any other important part. Its mode not however equidistant from both, but nearer 

 of insertion into the os calcis is also worthy to that of the flexor digitorum ; it rests upon 

 attention ; instead of being fixed into the whole the tibia and internal tibio-tarsal ligament, and 

 posterior surface of that bone, it occupies by is covered by the integuments and annular 

 its insertion merely the lower half of it ; supe- ligament; its venae comites run one upon 

 riorly the bone and tendon are not even in con- either side ; and the posterior tibial nerve lies 

 tact, for here a distinct synovial bursa is inter- close behind it, but as the vessel descends get- 

 posed between them. The liability of this ting gradually to its inner side. Notwith- 

 large bursa to inflammation and effusion should standing the few coverings of the artery in this 

 be carefully borne in mind by the surgeon : and situation, yet owing to the heel, the ankle, and 

 he who is aware of its office, placed as a friction the tendo Achillis projecting around, and bearing 

 roller between the tendon and bone, will duly off as it were those coverings from it, the vessel 

 estimate how much disease of this bursa will is here at a considerable depth from the surface ; 

 impede the motions of progression. Owing to and any one who supposes it can be easily found 

 the interposition of the bursa, rupture of the in the living subject, will form a very erroneous 

 tendo Achillis has occurred even below the idea of its true position: hence it is that all 

 upper edge of the os calcis ; and if, having cut good writers on surgical anatomy recommend 

 across the tendon, we forcibly extend the foot us to take up the artery in the lower third of 

 so as to elevate the heel, we shall at once com- the leg, rather than in the calceo-malleolar 

 prehend how indispensably necessary it is to groove. Several small vessels ramify about 

 maintain the extended position in our treatment the outer ankle, the external malleolar coming 

 of this important accident. from before meets here with the terminating 



b. Muscles. There are bu t few muscular fibres branches of the peroneal artery from behind, but 

 met with in the region of the ankle: the flexor these small vessels are interesting to the sur- 

 digitorum brevis arises upon the instep; and gical pathologist ralher than to the regional 

 posteriorly we find some of the fibres of the anatomist or operative surgeon. 



flexor pollicis longus, which are here continued d. Veins. Two veins, the "venae comites," 



down a considerable way upon the tendon. accompany each of the larger arteries : in all 



c. Arteries. The arteries about the ankle, operations upon the artery, the close apposition 



