DISSECTION OF THE POSTERIOR LIMB. 65 



ind the third into the fascia of the leg. Besides these, the 

 has an insertion into the circular mark behind the third 

 iter of the femur, by means of a fibrous band detached from the 

 irface of the muscle. 



m. — The anterior half of the muscle, in virtue of its attachment 

 patella, is an extensor of the stifle, and an abductor at the hip. 

 )8terior half of the muscle, with its insertions into the tibia and 

 of the leg, is a flexor and an outward-rotator at the stifle. When 

 Be-joint is kept extended, the lower end of the muscle becomes its 

 loint, and it then extends the pelvis on the femur, and aids in 



r 

 :>' 



Semitbndinosus (Plate 15). This muscle is placed at the 

 or border of the hip and thigh, where it occupies a position 

 jn the last-described muscle and the semimembranosus. The 

 ) is bifid superiorly, where it arises by one division from the 



spines and sacro-sciatic ligament, and by another and shorter 

 1 from the tuber ischii. Inferiorly it has a flat tendon, which is 

 d into the tibial crest, and whose posterior border blends with 

 3cia of the leg. 



lofi, — To flex the stifle and rotate the leg inwards. When the 

 s fixed, it can aid in rearing. 



! biceps femoris and semitendinosus muscles represent, apparently, 

 Luscles of the same name in man, plus portions of the gluteus 

 aus. Percivall describes the semitendinosus as representing also 

 imimembranosus of man. 



■ections. — The biceps must be carefully severed at its origin, and 

 I downwards. This will expose the aponeurotic layer that passes 

 th it from the superficial gluteus. A branch from the posterior 

 il nerves should be found entering the last-named muscle by turn- 

 arwards round the middle gluteus. Both branches of the super- 



gluteus should then be thrown downwards in order to fully 

 e the next mtiscle. 



e Middle Gluteus {Gluteus maximus of Percivall) (Plate 15) is a 

 le of great size and strength. It was partly exposed before the 

 sral of the superficial muscle. The fibres of the muscle arise from 

 .poneurosis of the common mass of the loins (longissimus dorsi), 

 the gluteal surface of the ilium, from the two ilio-saoral and the 

 -sciatic hgaments, and from the gluteal fascia. It has three distinct 

 constant insertions : 1. By a tendon, into the summit of the great 

 anter. 2. By another tendon, which plays over the convexity of the 



trochanter by means of a synovial bursa, and becomes inserted into 

 rest. 3. By a triangular fleshy slip, into the back of the trochan- 



ridge. 



,^^o^._To extend and abduct the hip. In the former of these 



