52 THE SURGICAL ANATOMY OF THE HORSE 



close to the nutrient foramen is a roughened, slightly elevated area 

 to which the tendon of insertion of the pectineus muscle is attached. 

 On the innei- border, and about two inches above the nutrient foramen, 

 is the internal or small trochanter. This is elongated from above to 

 below and is roughened. It gives attachment to the iliacus and psoas 

 magnus muscles, and from it the inner edge extends upwardly in the 

 form of a sharp, well-defined ridge, to the articular head. 



Immediately below the nutrient foramen we find a broad, well- 

 defined depression. This is the femoral groove, in which the femoral 

 vessels lie in intimate relationship to the bone. The groove is con- 

 sequently smooth, and it crosses the back of the bone in an oblique 

 direction downwards and outwards. Since the groove accommodates 

 the femoral artery, and the nutrient artery of the femur is a branch 

 of this vessel, it will be seen that the nutrient artery is very short, 

 for it passes directly to the nutrient foramen. 



Below the femoral groove and towards the inner side of the back 

 of the bone we find the supracondyloid crest. This is a roughened 

 elongated elevation, and from it the inner head of the gastrocnemius 

 muscle arises. Opposite this and towards the outer side of the bone is 

 a deep depression. This is the supracondyloid fossa, and it is bounded 

 by two well-defined edges or lips. These are curved, and meet one 

 another above and below in acute angles. The outer lip is roughened, 

 and from it the outer head of the gastrocnemius muscle arises. The 

 floor of the fossa, which is also roughened, gives origin to the superficial 

 flexor of the digit. Above the fossa the outer edge gradually rises 

 from the surface of the bone and curves outwardly to form the inferior 

 border of the piece of bone which projects prominently outwards with 

 a slight forward inclination. This projection is the external or third 

 trochanter, to which we have already referred. Its extremity is 

 roughened and gives attachment to the superficial gluteus muscle. 

 From the third trochanter the stout trochanteric ridge extends upwardly 

 to the back of the great trochanter. The posterior border of the ridge 



