THE HORSE IN MOTION. 39 



The ten nor vagimc femoris (Plate III., a, a) has its fibres spread 

 out beneath the skin and the broad fascia of the thigh. It has its fixed 

 insertion in the crest of the ilium, or hip; its fibres arc about eight 

 inches in length, and its weight not less than two pounds; its action, 

 direct and indirect, is upon the thigh to flex that bone upon the 

 pelvis ; from the shortness of its fibres its action as a flexor cannot 

 extend beyond three inches, but, being exerted at the commencement 

 of the flexion, when its aid is most required, it is very useful. It 

 is intimately associated locally and functionally with the superficial 

 glutens, which lias one of its attachments at the hip bone, and an- 

 other at the thigh bone, or femur, about one third of the distance 

 from its head. This portion, therefore, acts with the last mentioned 

 in flexing the thigh; the other branch extends alongside of the long 

 vastus, filling the angular space made by that muscle where it crosses 

 the great glutens. (This is made clear by Plate IV., where the muscle 

 under consideration is dissected away, along with the tensor vaginae 

 femoris.) It will be seen that it arises from the spine, in front of the 

 origin of the long vastus, v, v, v, and its tendinous insertion is at 6, 

 or third trochanter of the femur (see skeleton, Plate II., 6); the action 

 of this division is therefore that of an extensor, and directly over the 

 head of the femur at e, as we shall see when we come to consider the action 

 of the posterior extremity as a unit in locomotion. The action of this 

 muscle has been a controverted question. Blain teaches that it is a 

 flexor of the thigh, Bourgelot classes it with the extensors, and Chauveau 

 is of the opinion that it is an adductor. This confusion has evidently 

 arisen from confounding the action of its two branches. From these 

 two fixed insertions, so remote from each other, the fibres converge to 

 the movable insertion at the ridge on the femur, as already stated, 

 about one third down the length of the shaft, and between them the 

 fibres of the muscle are lost in the fibres of the underlying muscle and 

 barely distinguishable in the plate. The form of this muscle has never 

 indicated its use in locomotion, but when removed, as in Plate IV., its 

 value as an element of beauty is made apparent. 



The sartorius (Plate VI., i>) of the old authors, so called from its 

 analogue in man, and so called in man because it is the muscle which 



