336 THE MUSCLES. 



extensor, or with the fibrous bands furnishecJ to tliese tendons by the interosseous metacarpal 

 muscles. 



The external flexor of the metacarpus comports itself as in the Pig. But tlie oblique flexor 

 is covered by the perfoiatus, and its olecranian portion, thicker than in tlie other animals, is 

 only united to the principal fleshy body altogether inferiorily. The internal flexor is slender 

 and conoid ; its tendon, thin and long, reaches the metacarpus of the index. 



The 'perforatum of the Dog und Cat has a long, wide, and superficial body, separated from 

 the perforans by the oblique flexor of the metacarpus. Its tendon passes outside the carpal 

 sheath, and is divided into four branches, attached by their inferior extremity to the second 

 phalanx of the four principal digits. 



For the perforans, it is noted : 



1. That the radial portion of the muscle (the long flexor of the thumb in Man) commences 

 towards the superior extremity of the radius (Fig. 188, c, 4). 



'2. That the ulnar division is a semi-penniform muscle, attached by the superior extremities 

 of its fibres to nearly the whole extent of the posterior face of the ulnar (Fig. 188, c, 3). 



3. That the epitrochlean portion sends off, above tlie knee, a small particular fasciculus 

 terminating in a very thin tendon, which becomes lost in the fibrous arch of the carpal sheath 

 (Fig. 188, c, 6). This small muscle represents the palmaris brevis of Man. 



The terminal tendon divides into five branches, one for each digit (Fig. 188, d, 4, etc.). 



There have been already described in these animals : 



1. Two external radial muscles, only distinct at their terminal extremity, and confounded 

 for the remainder of their extent. This is the anterior extensor of the metacarpus in Solipeds 

 (Fig. 188, A, 5, 6, 7). 



2. A long abductor of the thumb, which appears to be the representative of the analogous 

 muscle, and the short extensor of the same digit in Man. It is the oblique extensor of the 

 metacarpus in the Horse (Fig. 188, a, 8). 



3. A common extensor of the digits ; the anterior extensor of the phalanges in the Horse 

 (Fig. 188, A, 11). 



4. A proper extensor of the three external digits, the proper extensor of the little finger in 

 Man, or lateral extensor of the phalanges in the Horse (Fig. 188, a, 10). 



5. A posterior ulnar, or external flexor of the metacarpus in the Horse (Fig. 188, a, 13). 



6. An anterior ulnar, or oblique flexor of the metacarpus in the Horse (Fig. 188, D, 6). 



7. A great palmar, corresponding to the internal flexor of the metacarpus in the Horse 

 (Fig. 188, B, 8). 



8. A small palmar, a dependency of the deep flexor of the phalanges (Fig. 188, c, 6). 



9. A flexor suhlimis of the phalanges (Fig. 188, D, 1). 



10. A deep flexor of the phalanges (Fig. 188, c. .5 ; D, 3). 



11. A long flexor of the thumb, united to the preceding muscle (the radial portion of the 

 perforans (Fig. 18S, c, 4). 



But in Carnivora there are five additional museles, which are not generally found in the 

 other animals. These are : the proper extensor of the thumb and index, long supinator, short 

 supinator, round pronator, and the square pronator. A special description will be given of these. 



Muscles proper to the Forearm of Carnivora. 



1. Proper Extensor of the Thumb and Index (Fig. 188, a, 11; b, 3). 



Synonyms. — The extensor secundi internodii pnUicis and extensor indicts of Man. 



This is a very small muscle, composed of a fleshy body and a tendon. The first is thin and 



fusiform, and is situated under the lateral extensor; it has its origin with the oblique extensor 



of the metacarpus at the external side of the radius. The tendon crosses the anterior aspect of 



the knee, enveloped by the synovial sheath of the common extensor of the digits, under which 



it passes. It divides into two branches, one of which goes to the thumb, the other to the index.' 



2. Long Supinator (Fig. 188, a, 12; c, 8). 



This muscle only exists in the rudimentaiy state in Carnivora. Its existence in the Dog 

 has even been denied, but this is an error; our researches have demonstrated that it is present, 

 in a more or less evident manner, in all breeds. 



It is a very delicate baud, situated in front, and on the inner side of the anterior extensor 



' In very powerful Horses, and more frequently in the Ox, we have met with traces of this 

 muscle in the form of a deep fasciculus situated in front of the lateral extensor. 



