THE FEMORAL ARTERY. 491 



muscular septum and supply the integument on the outer and posterior aspects of 

 the thigh. All these offsets anastomose with one another, the upper ones also with 

 the sciatic and internal circumflex arteries, and the lower ones with branches of the 

 popliteal artery. Much diminished in size, the perforating arteries are continued 

 outwards, winding round the back of the femur, the first passing through the inser- 

 tion of the gluteus maximus and the others through the short head of the biceps 

 and the external intermuscular septum, to terminate in the vastus externus and 

 crureus muscles, where they anastomose with branches of the external circumflex 

 artery. 



(a) The fir si perforating artery passes backwards at the lower border of the pec- 

 tineus muscle, through the fibres of the adductor brevis and adductor magnus, to 

 both of which it furnishes branches, and is distributed mainly to the hamstring 

 muscles and the lower end of the gluteus maximus. One branch ascends beneath 

 the latter muscle on the back of the femur, and joins in the anastomosis in the 

 hollow internal to the great trochanter with the gluteal, sciatic and internal cir- 

 cumflex arteries. Only a very small vessel is continued through the gluteus maxi- 

 mus into the vastus externus muscle. 



(Z>) The second perforating artery is frequently united at its origin with the first, 

 a little below which it pierces the adductor brevis and magnus muscles. 



(c) The third perforating artery pierces the adductor magnus muscle below the 

 insertion of the adductor brevis. The principal medullary artery of the femur is 

 derived from either the second or third perforating artery. 



(d) The fourth perforating artery supplies chiefly the short head of the biceps 

 muscle. It frequently gives a second artery to the femur. 



6. Muscular branches. In Scarpa's triangle the femoral artery gives some 

 small branches to the surrounding muscles. In Hunter's canal a variable number 

 of larger branches is given off 7 to the sartorius, vastus internus, and adductor 

 muscles. A constant branch, of considerable size, arises from the femoral artery 

 near its termination (sometimes from the beginning of the popliteal) and passes 

 outwards close to the back of the femur, perforating the short head of the biceps 

 and the external intermuscular septum, to end in the outer part of the crureus 

 muscle. 



7. The anastomotic artery (iv) arises from the femoral close to the opening 

 in the adductor magnus muscle, and immediately divides into two branches, super- 

 ficial and deep, which are, however, not unfrequently given off separately from the 

 femoral trunk. 



(a) The superficial branch accompanies the internal saphenous nerve to the inner 

 side of the knee, giving offsets to the lower parts of the sartorius and gracilis 

 muscles, and ends by supplying the skin of the upper and inner part of the leg. 

 Small twigs anastomose over the inner tuberosity of the tibia with the lower internal 

 articular artery of the popliteal. 



() The deep branch descends, embedded in the fibres of the vastus internus 

 muscle, along the front of the adductor magnus tendon to the inner condyle of the 

 femur, where it anastomoses with the internal articular arteries. It supplies the 

 vastus internus and crureus muscles, and sends small offsets outwards across the 

 front of the femur, as well as one of larger size at the upper border of the patella, to 

 join the superior external articular artery from the popliteal. 



Varieties of the femoral artery and its branches. In some rare cases the main artery 

 of the lower limb has been found springing from the internal iliac trunk, being continued 

 from a greatly enlarged sciatic artery, and descending with the great sciatic nerve along the 

 back of the thigh to the popliteal space, where its connections and ending are similar to those 

 of the vessel having the normal arrangement. The external iliac artery is then small, and 



