G4 THE ANATOMY OF THE HORSE. 



Directions. — The dissector shoiild, in the next place, direct his atten- 

 tion to the strong fascia covering the muscles in this region, after which 

 the fascia must be removed, and the mnscles cleaned and separated. 



Gluteal Fascia and Fascia Lata. The gluteal fascia forms a bluish- 

 white covering over the muscles of the hip, and by its deep face affords 

 origin to many fibres of the supei*ficial and middle gluteal muscles. It 

 is fixed above to the summits of the sacral spines and to the external 

 angle of the ilium, and between these points it is continuous forwards 

 with the tendon of the latissimus dorsi. It is prolonged downwards over 

 the muscles of the thigh, where it takes the name of the fascia lata. 

 This fascia lata receives in front the insertion of the tensor vaginae 

 femoris muscle, and it should not be removed until that muscle has been 

 examined. It forms a sheath for the muscles of the thigh, and is pro- 

 longed downwards over the leg. From its inner face a septum is sent in 

 between the vastus intcrnus and the biceps, to join the tendon of the 

 superficial gluteal muscle, and be inserted into the femur. 



The Tensor Vaginj^ Femoris (Plate 15). This muscle is situated 

 at the forepart of the thigh, in front of the superficial gluteal muscle, 

 from which it is somewhat difficult to separate it. It arises from the 

 external angle of the ilium, and it is inserted into the fiiscia lata. 



Action.- — It flexes the hip-joint. It also keeps the fascia lata tense, 

 and mechanically aids in keeping the stifle-joint extended. 



Directions. — The gluteal fascia and the fascia lata are now to be 

 removed. It is a matter of some difficulty to remove the former, as its 

 deep face has the muscular fibres taking origin from it, and these are 

 therefore exposed with a rough surfjice when it is removed. 



The Superficial Gluteus (Glntetts extemus of Percivall, part of the glu- 

 teus maximus of human anatomy) (Plate 15). The outline of this muscle 

 is not distinctly recognisable until the gluteal fascia has been removed. 

 It is then seen to have some resemblance to the letter V, having in its 

 upper border an indentation that divides it into an anterior and a 

 posterior branch. The anterior branch arises from the external angle 

 of the iliiim ; the posterior from the gluteal fascia. Both converge 

 to a common tendon, which is inserted into the third trochanter of the 

 femur (trochanter minor extemus). From the posterior branch of the 

 miiscle an aponeurotic layer passes backwards beneath the biceps, to 

 be inserted into the sacro-sciatic ligament and the tuber ischii. 



Action. — It is an abductor at the hip-joint. 



The Biceps Femoris (Plate 15). This is one of the largest muscles 

 in the body. It arises from the sacral spines, the fascia enveloping the 

 muscles of the tail, the sacro-sciatic ligament, the tuber ischii, and the 

 gluteal fascia. Inferiorly it has three divisions, one of which is inserted 

 into the anterior surface of the patella, a small synovial bursa being 

 interposed between the tendon and the bone, another into the tibial 



