270 



TEE MUSCLES. 



Fig. 123. 



DIFFEKENTIAL CHARACTERS OP THE MPSCLES OP THE FORE- 

 AKM IN OTHER THAN SOLIPED ANIMALS. 



Ei'MiNANTS. — In the Ox and Sheep, the anterior ex- 

 tensor of the metacarpus comports itself as in Solipeds. 



The oblique extensor of the metacarpus of the same 

 region terminates inside the upper extremity of the prin- 

 cipal metacarpus. 



The anterior extensor of the phalanges offers a remark- 

 able disposition. This muscle is divided throughout its 

 length into two parallel portions : an external, ^Yhich forms 

 the common extensor of the digits ; and an internal, the 

 proper extensor of the internal digit. 



a. The fleshy body of the common extensor (fig. 123, 3) 

 is a little more voluminous than that of the second muscle. 

 Its tendon (3') commences near the inferior third of the 

 radius, passes over the knee, the metacarpal bone, and the 

 metacarpo-phalangeal articulation. On arriving at the 

 origin of the digits it bifurcates, and each of its branches 

 goes to be inserted into the pyramidal eminence of the 

 third phalanx (3"). This muscle, in extending the digits, 

 brings them togefiier, as M. Lecoq has judiciously re- 

 marked. 



6. The proper extensor of the internal digit ( fig. 123, 4) 

 much resembles the common extensor in volume, form, 

 and direction. Its tendon (4') passes, with tliat termi- 

 nating the latter muscle, into one of the inferior grooves 

 of the radius and over the capsular ligament of the carpus, 

 where the two cords are enveloped by a common synovial 

 sheath. Arrived at the metacarpo-phalangeal articulation, 

 tills tendon is placed at the excentric side of the internal 

 digit, and descends, gradually expanding, until it reaches 

 the inferior extremity of this bone ; towards the middle of 

 the first phalanx, it receives from the suspensory ligament 

 of the fetlock two constraining bands similar to those 

 which, in Solipeds, bind the anterior extensor of the pha- 

 langes on the same bone. This tendon bifurcates infe- 

 riorly ; one of its branches is attached to the anterior face 

 of the second phalanx ; the other, much wider than the 

 MUSCLES OF THE FORE-ARM first, covcrs the conimon external lateral ligament of the 

 OP THE ox ; EXTERNAL FACE, two inter-phalangeal articulations, and terminates on the 

 1, Anterior extensor of the whole external side of the third phalanx. In the Sheep, 

 metacarpus; 1', Insertion of this second branch is feeble, and is directed towards the 

 its tendon ; 2, Oblique ex- lieel, which it envelopes by uniting its fibres with the per- 

 forans tendon and the plantar cushion. 



The lateral extensor of the phalanges of Emninants is 

 thicker than in the Horse, and constitutes the proper ex- 

 tensor of the external digit (fig. 123, .')). Its terminal 

 tensor of ihe internal digit ; tendon (4', 6, 7) comports itself exactly the same as that 

 4', Its tendon ; 5, Proper of the proper extensor of the internal digit, and conse- 

 extensor of the external quently does not merit a special description. We may 

 digit ; 5', Its tendon ; 6, Its remark, with M. Lecoq, that these two muscles separate 

 branch of insertion into the the digits from each other in extending them ; they are, 

 second phalanx ; 7, Branch therefore, to a certain point, antagonists of the common 

 to the third phalanx ; 8, extensor. 



External flexor of the meta- The perforatus of the Ox and Sheep is composed of 



carpus ; 9, Olecranian por- two portions, whose tendons unite towards the middle of 

 the metacarpal region. The single tendon (fig. 124, 1, 2, 3) 

 which results from this union afterwards divides into two 

 branches, each of which comports itself, in regard to the 



tensor ; 3, Common extensor 

 of the digits; 3', Its tendon; 

 3", Terminal bifurcation of 

 that tendon ; 4, Proper ex- 



tion of the perforans ; 10, 

 Tendon of the perforans ; 

 11, Tendon of the perfo- 

 ratus ; 12, Suspensory liga- 

 ment of the fetlock; 13, 



The band it furnishes to the perforatus to form the ring through which the perforans 

 passes ; 14, The external band it gives off to the proper extensor of the external digit; 

 15, Coraco-i-adialis ; 16, Anterior brachial; 17, Anconeus. 



