262 OUTLINES OF EQUINE ANATOMY. 



serted as above mentioned into tlie inner small trochanter. 

 Externally it is ir^ contact with the origin of 



Hectus femoris. This muscle combines mth the two 

 vasti to form that large fleshy mass which clothes the front 

 of the femur, by some anatomists described as a single 

 muscle under the term triceps extensor cruralis, since, 

 being inserted l>elow mto the upper surface of the patella, 

 they serve through the medium of its three straight liga- 

 ments to extend the tibia on the femur. Rectus femoris 

 arises by two fiat tendinous bands from the external and 

 internal surfaces of the neck of the ilium ; between these is 

 a bursa with a mass of fat. It passes over ilio-femoralis 

 at its attachment to the capsular ligament of the hip-joint, 

 and opposite, about the centre of the femur, blends with 

 the vasti. 



Vastus externiis arises from the antero-extemal part of 

 the femur, extending as high up as trochanter major, oppo- 

 site the middle third of the femur it blends with 



Vastus interims, which is attached to theantero-intemal 

 part of the superior two thirds of the femur. Between it 

 and vastus externus superiorly is the inferior attachment of 



Ilio-femoralis, a small muscular band attached supe- 

 riorly to the front of the neck of the ilium, below the heads 

 of rectus femoris-, passing over and becoming attached to 

 the capsular ligament of the hip- joint, which it prevents 

 from injury during movements, and becoming inserted 

 for aboat two inches and a half along the upper part of the 

 central line of the front of the femur. It thus corresponds 

 exactly to scapulo-humeralis posticus of the foi^ limb. 



In the attachments of the " triceps cruralis" to the patella 

 are distinguishable several synovial bursse, and between 

 rectus femoris and vastus internus run the main branch 

 of the crural nerve, and the inguinal artery and vein. 

 These parts just described are supplied with blood by the 

 external iliac artery, which arises from the posterior 

 aorta, where it passes on to the underneath surface of the 

 sacrum, about two inches before it breaks up to form the 

 internal iliac arteries. Just at its origin it gives off the 

 circumflex artery of the ilium, which runs forwards and 

 downwards to the antero-inferior spinous process of the 

 ilium, supi^lying in its course iliacus and proceeding on 

 inio the flank, where its terminal ramifications anastomose 

 with those of the lumbar, intercostal, internal thoracis-. 



