730 



SOLIPEDA. 



biceps (ileo-rotulien}, the vctstus interims, the 

 vastus externus, and the cruralis offer in all 

 quadrupeds the same general disposition as in 

 man, the three last forming one great common 

 muscle (trifemoro-rotulien). The anterior mar- 

 gin of the thigh in the horse and in other 

 quadrupeds is formed by the sartorius (ileo- 

 pretibien}, which here, from its position and 

 office, has been named by hippotomists the 

 " long adductor of the thigh" 



Fig. 503. 



Deep muscles of the thigh and ligaments of the pos- 

 terior extremity of the Horse. 



a, b, c. A muscle named by Stubbs " musculus 

 pirvus in articulatione femoris situs : it arises by a 

 flat tendon (6), from above the tendon of the rectus 

 cruris (d), and is inserted tendinous into the os fe- 

 nioris (c) ; i, k, I, iliacus internus. The small numerals 

 indicate the principal ligaments of the limb. 



The biceps (iscMo-peronien) in the horse and 

 the greater number of quadrupeds, not even 

 excepting the quadrumana, arises by a single 

 origin, which is derived from the ischium, and 

 the neighbouring ligaments and fascial expan- 

 sions. This muscle covers a large proportion 



of the outer surface of the thi^h : its principal 

 insertion is into the head of the fibula, but it 

 likewise throughout its whole length contracts 

 extensive and important attachments with the 

 fascia lata, so that it also becomes a powerful 

 extensor of the thigh. There is moreover, in 

 the horse and in the Ruminantia, a distinct 

 portion of the biceps derived from the sacro- 

 sciatic aponeurosis, the fibres of which are 

 directed obliquely from before backwards, 

 which, meeting the ischiatic portion at an 

 angle, form with it a kind of raphe, which is 

 prolonged for some distance. This muscle is 

 called by Bourgelat the " vastus longus " of 

 the thigh. 



The gracilis {pubio-pretibien) is in all quad- 

 rupeds a very considerable muscle, more especi- 

 ally in such as have the thigh much shortened, 

 as is the case in the horse, and the ungulata 

 generally. It is called by Bourgelat the " short 

 adductor of the thigh" whilst he gives the name 

 " gracilis" to the semitendinosus. 



The semimembranosus (ischio-sous-tibien) and 

 the semitendinosus (ischio-pretibien) have in all 

 quadrupeds the same origin and general ar- 

 rangement as in man ; but both of them are 

 in the lower animals inserted into the tibia by 

 a broad aponeurosis. It must also be remarked 

 that their insertion extends much lower down 

 than in the human subject, a circumstance 

 which causes the leg to be permanently kept 

 in a semiflexed condition ; and is one of the 

 great obstacles to their walking in an upright 

 position. Even in the Quadrumana these 

 muscles have their insertions very low down 

 in the leg. 



The poplitcEus has nothing remarkable in its 

 disposition. 



Muscles implanted into the fo"t. The gas- 

 trocnemii (bi-femoro-calcanien) and the solceus 

 (tibio-calcanien) are less considerable muscles, 

 as regards their comparative size in quadru- 

 peds, than in the human race : nevertheless 

 their general disposition is invariably the same 

 as in man. In the Solipeda, the solans is 

 remarkably slender and feeble. 



The plantaris (femori-calcanien*). In the 

 Solipeds this muscle is remarkably developed, 

 so much so indeed as apparently to repre- 

 sent the flexor sublimis. In the horse this 

 muscle arises under the external head of 

 the gemellus from a large fossa in the os fe- 

 moris above the external condyle : its tendon 

 is continued downwards, and runs over the 

 extremity of the os calcis, where it is en- 

 closed in a sheath formed by strong liga- 

 ments, which prevent it from slipping out of 

 its place; passing on from this point, it di- 

 vides, to be inserted upon each side of the 

 posterior surface of the great pastern bone 

 towards its inferior extremity, here giving 

 passage between its two insertions to the ten- 

 don of the long flexor of the toe, which it 

 serves to bend down closely to the pastern 

 when the fetlock joint is bent, thus seeming 

 to perform the functions both of the p/antatis 

 and of the short flexor of the toes. 



The tibialis anticus. In the Ruminantia 

 and in the Solipeds, the tibialis anticus is im- 



