MUSCLES OF THE POSTERIOR LIMBS. 295 



The semitendinosus has no sacral prolongation ; it arises only from the ischium. 



The semimembranosiis is divided, inferiorly, into two brandies : one, very thick, 

 passes to the femur ; the other, much smaller, terminates by a tendon which is in- 

 sinuated beneath the internal lateral ligament of the ftmoro-tibial articulation, to gain 

 the superior extremity of the tibia. 



CAKNIVORA. In these animals it is somewhat difficult to isolate the two portions of 

 the long vastus from each other. The anterior only proceeds from the isrhium. Infe- 

 riorly, they terminate in common by an aponeurosis which passes to the tibial crest and 

 tiie external patellar ligament. 



The semitendinosus and semimembranosus comport themselves as in the smaller 

 Kumiuants. 



C. Internal Crural Region. 



RUMINANTS. The long adductor of the leg in the Ox and Sheep is traversed, near its 

 origin, by the femoral artery. The pectineus of the Ox, single at its upper extremity, is 

 divided into two branches at its inferior extremity. One of these brunches, thin and 

 pale, is prolonged to near the internal condyle of the femur, while the principal stops, as 

 in the Horse, on the posterior face of the bone. 



The small adductor of the thigh is scarcely distinct from the great adductor. The 

 latter is undivided at its inferior extremity, which stops at the posterior face of the 

 femur without going to the inner condyle of that bone. 



The internal obturator has no upper portion ; it is united to the external obturator in 

 passing through the oval foramen. 



PIG. In this animal, the internal crural muscles ofter somewhat the same disposition 

 as in the Ox. 



CARNIVORA. In the Dog and Cu, the long adductor of the leg arises from the 

 external angle of the ilium, and by its muscular portion is prolonged to the inner face of 

 the tibia. The short adductor is much thinner and narrower than in the other animals. 

 The small adductor of the thigh is a little, dist nctly-isolated, muscle, which begins on the 

 inferior face of the pubis, and terminates ai the posterior face of the femur, below the 

 square crural. The great adductor is, on the contrary, a wide, thick, undivided muscle, 

 attached to nearly the whole extent of the linea aspera of the femur. 



There is nothing particular to note with regard to the square crural and the 

 obturators ; the gemelli of the pelvis are always composed of two small, distinctly-isolated, 

 fasciculi, which comport themselves as in Man. 



COMPARISON OF THE MUSCLES OP MAN*S THIGH WITH THOSE OF THE THIGH OF ANIMALS. 



A. Anterior Muscles. 



The anterior gradlis is not found in Man ; nevertheless, there are reckoned three 

 anterior muscles of the thigh, as the sartoi ius, which corresponds to the long adductor 

 of the leg of animals, is included in this region. 



The srtorius is a very long muscle, whose width at most is about two fingers* breadth. 

 It is attached above, not to the lumbo-iliac aponeurosis, but to the anterior and superior 

 iliac spine : it is afterwards directed downwards and inwards, to pass round the internal 

 condyle of the femur, and terminate by an expanding tendon at the crest of the tibia. 



The tnisor of the fascia latn. (tensor xaginse femoris] shows the same general dis- 

 position observed in animals. It is the same with the femoral triceps. The anterior 

 rectus arises l>y two tendinous branches : one is detached from the anterior and inferior 

 iliac spine ; the other from the brim of the cotyloid cavity. 



B. Muscles of the Posterior Region. 



Those are three in number: the femoral or crural biceps, semitendinosus, and 

 Bemimembranosus. 



The femoral biceps is represented in Solipeds by the posterior portion of the long 

 vastns. It is an elongated muscle arising by two heads: the long head comes from the 

 ischiatic tuberosity ; the shortest from the middle of the linea aspera. After their 

 union, these two heads give rise to a tendon which is fixed into the head of the fibula, 

 and sends an expansion over the tibinl aponeurosis. 



The semHendinosus arises in common with the long head of the biceps ; its inferior 

 tendon is reflected beneath the internal tuberosity of the tibia, to be fixed into the crest 



