454 THE ANATOMY OF THE HORSE 



THE DEEP MUSCLES OF THE ILIO-FEMORAt 

 REGION 



Four small muscles attach the fossa of the trochanter major to the 

 pelvis, and rotate the femur outwards. 



Pyriformis. — Origin — from the transverse processes of the sacrum, and 

 the internal face of the ilium by fleshy fibres, which are inserted into the 

 trochanteric fossa. Action — to rotate the femur outwards. 



Obturator externus and internus are attached, one to the outside and 

 the other to the inside of the margins of the obturator foramen, and to 

 the two faces of the fascia which fills it up. Insertion — by separate 

 tendons into the trochanteric fossa. 



Gemini a7-ise by two bundles of fibres from the supero-posterior part 

 of the ischium. Insertion — to the trochanteric fossa. Action — the same as 

 the three last-named muscles. 



ANTERIOR FEMORO-CRURAL REGION 



Extensor pedis lies superficially on the anterior part of the leg. 

 Origin — from a depression on the antero-inferior and external part of the 

 external condyle of the femur. Insertion — to the coronal process of the os 

 pedis. Action — to flex the hock and extend the foot. 



Peroneus lies on the antero-external side of the leg. Origin— ivom. 

 the head of the fibula and outer part of the tibia. Insertion — to the 

 supero-anterior part of the os suffraginis. Action — to assist the foregoing 

 muscle. 



Flexor metatarsi is situated on the antei'o-internal side of the leg. 

 Origin — in common with the extensor pedis, from the outer condyle of 

 the femur, and from the upper part of the anterior face of the tibia. 

 Insertion — to the os cuboides and to the large and small metatarsal bones. 

 Action — to flex the hock. 



POSTERIOR FEMORO-CRURAL REGION 



Gastrocnemius externus lies along the posterior part of the leg. 

 Origin — in two portions from the fossa just behind and above each condyle 

 of the femur. Insertion — to a depression on the centre of the point of the 

 OS calcis. Action — to elevate the point of the hock, and thus to extend 

 the leg. 



Gastrocnemius internus is situated on the postero-mesian part of tlie 

 leg. Origin — from the inner part of the ridge which surrounds the fossa 

 behind and between the two condyles of the femur. Insertio7i — above 

 the hock it becomes tendinous, and passes over the point (from which it is 

 separated by a large bursa mucosa, the scat of capped hock), and descends 

 along the back of the flexor tendons, where it corresponds with the flexor 



