BRANCHES OF THE POPLITEAL ARTERY. 583 



with considerable difficulty, 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 supine position, with the knee flexed and the thigh rotated outward, so that it rests on 

 its outer surface ; an incision three inches in length, beginning at the junction of the middle 

 and lower third of the thigh, is to be made parallel to and immediately behind the tendon of 

 the Adductor magnus, and the skin, superficial and deep fasciae divided. The tendon of the 

 muscle is thus exposed, and is to be drawn forward and the hamstring tendons backward. A 

 quantity of fatty tissue will now be opened up, in which the artery will be felt pulsating. This 

 is to be separated with the point of a director until the artery is exposed. The vein and nerve 

 will not be seen, as they lie to the outer side of the artery. The sheath is to be opened and 

 the aneurism needle passed from before backward, keeping its point close to the artery for fear 

 of injuring the vein. The only structure to avoid is the long saphenous vein in the superficial 

 incision. The upper part of the popliteal artery may also be tied by an incision on the back of 

 the limb, along the outer margin of the Semimembranosus, but the operation is a more difficult 

 one, as the internal popliteal nerve and the popliteal vein are first exposed, and great care has 

 to be exercised in separating them from the arterj". 



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 prone position with the limb 

 extended. 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. 



Branches. The branches of the popliteal artery are the 



lyr I f Superior. Superior External Articular. 



\ Inferior or Sural. Azygos Articular. 



Cutaneous. Inferior Internal Articular. 



Superior Internal Articular. Inferior External Articular. 



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

 part of the popliteal artery, and are distributed to the lower part of the Adductor 

 magnus and flexor muscles of the thigh, anastomosing with the fourth perforating 

 branch 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. 



The cutaneous branches arise separately from the popliteal artery or from 

 some of its branches; they descend between the two heads of the Gastrocnemius 

 muscle, and, piercing the deep fascia, are distributed to the integument of the 

 calf. One branch usually accompanies the short, or external, saphenous vein. 



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 winds inward beneath the hamstring 

 muscles, to which it supplies branches, above the inner head of the Gastrocnemius, 

 and, passing beneath the tendon of the Adductor magnus, divides into two 

 branches, one of which supplies the Vastus internus, inosculating with the anasto- 

 motica 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. This branch is frequently of small size, a 

 condition which is associated with an increase in the size of the anastomotica 

 magna. The external branch passes above the outer condyle, beneath the tendon 

 of the Biceps, and divides into a superficial and deep branch : the superficial 

 branch supplies the Vastus externus, and anastomoses with the descending branch 

 of the external circumflex and the inferior external articular arteries ; the deep 

 branch supplies the lower part of the femur and knee-joint, and forms an anasto- 

 motic arch across the bone with the anastomotica magna and the inferior internal 

 articular arteries. 



