SOLIPEDA. 



729 



f, glutaeus internus ; b, iliacus interims ; 10, vastus 

 interims ; 33, sciatic nerve ; 23, poplitseus ; 25, 26, 

 tibialis posticus ; 28, 29, 30, 31, flexor longus digit! 

 pedis ; 24, poplitaeal nerve ; 38, posterior tibial nerve ; 

 40, articular ligaments of the knee ankle and pastern 

 joints ; 26, insertion of the tendon of the tibialis 

 posticus into 29, that of the flexor longus digiti 

 pedis; 11, flexor brevis digiti pedis; 31, insertion 

 of the tendon of the flexor longus into the coffin 

 bone ; 41, internal cartilage of the hoof. 



The extensor proprius minimi digiti. In 

 the horse this muscle is represented by two 

 muscles. One of these, called by Bourgelat 

 the lateral extensor of the foot, and by Lafosse 

 the extensor of the pastern, is inserted by the 

 intervention of a strong tendon into the side 

 of the first phalanx of the solitary toe that 

 forms the foot. The second muscle, placed 

 between the above and the preceding* muscle, 

 furnishes a similar tendon, which, after passing 

 in front of the carpus, becomes united at an 

 acute angle with that of the former, the two 

 co-operating with each other in extending the 

 foot. 



In the Ruminantia likewise this muscle is 

 disposed after two different manners. In the 

 Cervitlae or deer tribe, in which the rudimen- 

 tary toes are capable of distinct movements, 

 it furnishes two tendons to the two outer 

 toes ; whilst in oxen, goats, sheep, and an- 

 telopes its tendon presents a double inser- 

 tion one into the posterior aspect of the 

 outer finger, the other into the tendon of the 

 extensor communis. 



The extensor proprius indicis and the two 

 long extensors of the thumb are, in all the 

 ungulate quadrupeds, entirely wanting. 



The abductor longus pollicis is present in all 

 the mammalia, even in the Ruminantia and 

 the Solipeds. In the horse its tendon is 

 implanted into the internal surface of the base 

 of the cannon bone, so that it thus becomes an 

 extensor of the foot (I'extenseur oblique du 

 canon of Bourgelat). 



The flexor digitorum sublimis perforatus and 

 \heflexor profundus perforans. In the horse 

 these muscles arise in common from the in- 

 ternal protuberance of the os humeri. and the 

 two are confounded together for a consider- 

 able distance, when the two muscles separate 

 to form two distinct tendons ; of these, that 

 belonging to the flexor sublimis runs beneath 

 the annular ligaments of the carpus, to be in- 

 serted into the base of the great pastern bone 

 previously dividing to give passage to the 

 tendon of the profundus on its way to be im- 

 planted into the last phalanx or coffin bone of 

 the foot. 



In the ungulata the small muscles of the 

 hand would evidently be useless, and accord- 

 ingly in the horse all traces of them are lost, 

 their place being supplied by the peculiar 

 structure of the foot, to be described further 

 on. 



Posterior Extremity Muscles of the Pelvis. 

 The muscles specially belonging to the pel- 

 vis are the quadratus lumborum and the psoas 

 parvus, which in quadrupeds offer precisely 

 the same arrangement as in man. 



Muscles inserted into the os femoris These 



are similarly disposed in all the Mammifera 

 possessed of a pelvic extremity, the only differ- 

 ences observable being in their proportionate 

 sizes. In the Solipeda the analogue of the 

 glutaeus mctximus is so small, in comparison of 

 the two other glutcei, that it is named by 

 Bourgelat " le petit fessier" and by Stubbs 

 the glutaeus externus. In the human subject 

 the comparative large size of this muscle is 

 rendered necessary in consequence of the 

 erect attitude of the body, which it princi- 

 pally assists in maintaining; whilst in quadru- 

 peds, from the horizontal position of their 

 bodies, it becomes of very secondary import- 

 ance. In the horse it is a comparatively 

 slender muscle, deriving its principal origin 

 from the sacral fascia, but also reinforced 

 by a long slender fasciculus, which descends 

 immediately from the upper portion of the 

 ileum. Its insertion is into the third tro- 

 chanter and external rough surface at the upper 

 part of the thigh bone, and also by strong 

 tendinous aponeuroses into the fascia lata. 



The Glutceus medius is the principal muscle 

 in this region ; it arises extensively from 

 the sacro-iliac aponeurosis, and from the ex- 

 ternal surface of the ileum, from which origin 

 it runs downwards and forwards to be im- 

 planted into the outer surface of the great 

 trochanter, and is, moreover, prolonged, by 

 means of a strong posterior fasciculus, to- 

 wards the lower extremity of the femur. From 

 this latter circumstance, as well as from its 

 preponderating strength, the glutaeus medius 

 may be regarded as being, par exceVence, the 

 kicking muscle in these quadrupeds which in- 

 stinctively have recourse to this mode of de- 

 fence as best suited to their organization. 



The other muscles inserted into the great 

 trochanter namely, the glutceus minimus, the 

 quadratus femoris, the obturator externus, the 

 obturator internus, the gemelli, and the pyra- 

 midalis present in all quadrupeds a disposi- 

 tion similar to that which they have in the 

 human body. 



The muscles passing between the pelvis and 

 the lesser trochanter, and also those that arise 

 from the pubis to be implanted into the in- 

 ternal surface of the thigh, in the generality of 

 quadrupeds, correspond very accurately with 

 those of man. In the horse these are the 

 psoas magnus, the iliacus, the pcctinceus, and 

 the triple adductor, none of which offer any 

 peculiarity worthy of remark. 



The flexor muscles of the leg are the biceps 

 flexor cruris, the semimembranosus, the aemi- 

 tendinosus, the sarlorius, the gracilis, and the 

 poplitceus, all of which are enclosed by the 

 dense fascia of the thigh, or fascia lata, which 

 is kept tense by the action of a special muscle 

 named the tensor vagintE femoris. 



The last-named muscle, called also the 

 nrusculus fasciae lata: (ileo-fascien) arises in the 

 horse from the anterior portion of the crest 

 of the ileum, whence it descends obliquely 

 downwards, enclosed between two layers of 

 the fascia, covering the thigh, into wh.ch it is 

 strongly inserted. 



The extensor muscles of the thigh v'z. the 



