BRANCHES OF THE POPLITEAL ARTERY. 639 



femur or by antero-posterior dislocation of the knee-joint. It has been torn in breaking down 

 adhesions in cases of fibrous ankylosis of the knee, and is in danger of being wounded, and in 

 fact has been wounded, in performing Macewen's operation of osteotomy of the lower end of the 

 femur for genu valgum. In addition. Spencer records a case in which the popliteal artery was 

 wounded from in front by a stab just below the knee, the knife passing through the interosseous 

 space. The popliteal artery is more frequently the seat of aneurism than is any other artery 

 in the body, with the exception of the thoracic aorta. This is due no doubt, in a great 

 measure to the amount of movement to which it is subjected, and to the fact that it is supported 

 by loose and lax tissue only, and not by muscles, as is the case with most arteries. 



Ligature of the popliteal artery is required in cases of wound of that vessel, but for aneurism 

 of the posterior tibial it is preferable to tie the superficial femoral. The popliteal may be tied 

 in the upper or lower part of its course : but in the middle of the ham the operation is attended 

 with considerable difficult}', from the great depth of the artery and from the extreme degree of 

 tension of the lateral boundaries of the space. 



In order to expose the vessel in the upper part of its course the patient should be placed in 

 the prone position, with the limb extended. An incision about three inches in length should 

 then be made through the integument, along the posterior margin of the Semimembranosus, 

 and. the fascia lata having been divided, this muscle must be drawn inward. The internal pop- 

 liteal nerve will be first exposed, lying very superficial and external to the artery ; beneath this 

 will be seen the popliteal vein, and, still deeper and to its inner side, the artery. The vein and 

 nerve must be cautiously separated from the artery, and the aneurism needle passed around the 

 vessel from without inward. 



To expose the vessel in the lower part of its course, where the artery lies between the two 

 heads of the Gastrocnemius. the patient should be placed in the same position as in the preceding 

 operation. An incision should then be made through the integument in the middle line, com- 

 mencing opposite the bend of the knee-joint, care being taken to avoid the external saphenous 

 vein and nerve. After dividing the deep fascia and separating some dense cellular membrane, 

 the artery, vein, and nerve will be exposed, descending between the two heads of the Gastrocne- 

 mius. Some muscular branches of the popliteal should be avoided if possible, or, if divided, tied 

 immediately. The leg being now flexed, in order the more effectually to separate the two heads 

 of the Gastrocnemius the nerve should be drawn inward and the vein outward, and the 

 aneurism needle passed between the artery and vein from without inward. 



In cases where the artery has been wounded during an osteotomy of the lower end of the 

 femur it would be most conveniently secured from the front at the inner side of the thigh. The 

 knee is flexed and the limb placed on its outer side. An incision, three inches long, is made 

 parallel to and immediately behind the tendon of the Adductor magnus from the junction of the 

 middle and lower third of the thigh. Skin, superficial and deep fascia are to be divided, care 

 being taken of the internal saphenous vein ; the Adductor magnus is to be drawn forward and 

 the inner hamstring tendons backward, and the artery will be found surrounded by fat. The 

 nerve and vein are usually not seen, as they lie to the outer side of the artery. 



The branches of the popliteal artery are the 



tr i . f Superior. Superior Internal Articular. 



^Muscular 's T / 01 A * ^ - i 



( Interior or bural. Azygos Articular. 



Cutaneous. Inferior External Articular. 



Superior External Articular. Inferior Internal Articular. 



The superior muscular branches, two or three in number, arise from the upper 

 part of the popliteal artery, and are distributed to the Vastus externus and flexor 

 muscles of the thigh, anastomosing with the inferior perforating and terminal 

 branches of the profunda. 



The inferior muscular (sural) are two large branches which are distributed to 

 the two heads of the Gastrocnemius and to the Plantaris muscle. They arise from 

 the popliteal artery opposite the knee-joint. 



Cutaneous branches descend on each side and in the middle of the limb, between 

 the Gastrocnemius and integument ; they arise separately from the popliteal artery 

 or from some of its branches, and supply the integument of the calf. 



The superior articular arteries, two in number, arise one on each side of the 

 popliteal, and wind round the femur immediately above its condyles to the front 

 of the knee-joint. The internal branch passes beneath the tendon of the Adductor 

 magnus, and divides into two, one of which supplies the Yastus internus, inoscu- 

 lating with the anastomotica magna and inferior internal articular ; the other 

 ramifies close to the surface of the femur, supplying it and the knee-joint, and 

 anastomosing with the superior external articular artery. The external branch 

 passes above the outer condyle. beneath the tendon of the Biceps, and divides into 



