MUSCLES OF THE POSTEBIOB LIMBS. 295 



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



The semimembranosus is divided, inferiorly, into two branches : one, very thick, 

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

 sinuiited beneath the internal lateral ligament of the femoro-tibial articulation, to gain 

 the superior extremity of the tibia. 



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

 the hug vastus from each other. The anterior only proceeds from the ischium. Infe- 

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

 tbe (xtcrnal patellar ligament. 



The semitendiiiosus and semimembranosus comport themselves as in the smaller 

 Kumiuants. 



C. Internal Crural Begion. 



EuMiNANTS. — The long adductor of the leg in the Ox and Slieep is traversed, near its 

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

 divided into two branches at its inferior extremity. One of these brunches, tl;in and 

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

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



The small adductor ofihe 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 nf that bone. 



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

 passing through the oval foi amen. 



Pig. — In this animal, the internal crural muscles offer somewhat the same disposition 

 as in the Ox. 



Caenivoka. — In the Dog and Cat, the long adductor of the leg arises from the 

 exteiUiil an>;le of the ilium, and by its muscular portion is prolonged to the inner face of 

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

 The smaM adductor of the thigh is a little, disfnctly -isolated, muscle, which begins on the 

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

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

 attached lo nearly the whole extent of the linea aspeia of the femur. 



There is nothing particular to note with reg.ird 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. 



COMPAEISON OF THE MUSCLES OF MAn's THIGH WITH THOSE OP THE THIGH OF ANIMALS. 



A. Anterior Muscles. 



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

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

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



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

 It is attached above, not to the lumbo-iliae aponeurosis, but to the anteritir and superior 

 iliac spine : it is afterwards directed downwanls and inwards, to pa^s round the internal 

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



The tnsor of the fascia lata (tensor vagina; femoris) shows the same general dis- 

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

 rectus arises hy 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 Begion. 

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



eemimembranosus. „,.,-,,, ^ ■ ,.. c it, , 



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

 vastus It is an elongated muscle arising by two heads : the long heail comrs from the 

 ischiatio tuberosity ; the shorttst from the middle of the liuea 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 tibiul aponeurosis. ,,,„,. -^ . -■ • 



The semitendinosus arises in common with the long head ot the biceps ; its interior 

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



