626 ARTERIES. 



operation is attended 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 prono 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 inwards, when the pulsation 

 of the vessel will be detected with the finger ; the nerve lies on the outer or fibular side of the 

 artery, the vein, superficial, and also to its outer side ; the vein having been cautiously separated 

 from the artery, the aneurism needle should be passed around the latter vessel from without 

 inwards. 



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 preced- 

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

 commencing opposite the bend of the knee-joint, care being taken to avoid the exteinal saphe- 

 nous vein and nerve. After dividing the deep fascia, and separating some dense cellular mem- 

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

 Gastrocnemius. 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 inwards and the vein outwards, 

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



The branches of the popliteal artery are, the 



Muscular j ^rior'or Sural. 



Cutaneous. 



Superior external articular. 



Superior internal articular. 



Azygos articular. 



Inferior 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 either 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 Vastus 

 Internus, inosculating with the anastomotica magna and inferior internal arti- 

 cular; 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 a superficial and deep branch : the superficial branch supplies 

 the Vastus Externus, and anastomoses with the descending branch of the exter- 

 nal circumflex artery; the deep branch supplies the lower part of the femur 

 and knee-joint, and forms an anastomotic arch across the bone with the anas- 

 tomotica magna artery. 



The azygos articular is a small branch, arising from the popliteal artery oppo- 

 site the bend of the knee-joint. It pierces the posterior ligament, and supplies 

 the ligaments and synovial membrane in the interior of the articulation. 



The inferior articular arteries, two in number, arise from the popliteal, be- 

 neath the Gastrocnemius, and wind round the head of the tibia, below the 

 joint. The internal one passes below the inner tuberosity, beneath the internal 

 lateral ligament, at the anterior border of which it ascends to the front and 



