376 THE MUSCLES. 



The first comprises the crural triceps and tlie plantaris. The triceps itself is eoiuposed ot 

 the gastrocnemius, of whicli we will say nothing, and the soleus. The latter is flattened fmm 

 before to behind, attached to the upper third of the fibula, the oblique line of the tibia, and 

 the middle tiiird of the inner border of this bone, and terminated by an aponeurotic lamina 

 which is blemled with the tendo-Achilles. The plantaris is formed by a su.all fusiform 

 muscular body, situattd beneath the external gemellus, then by a long slender tendon, which 

 is confounded with the inner border of the tendo-Achilles, or is inserted into the os calcis. 



The deep layer is comimsed of four muscles : 



1. The poplitens, whii-h in its attachments and position resembles that of animals. 



2. The common long flexor of the toes, corresponding to the oblique flexor of animals. It is 

 an elongated penniform muscle, fixed ab(jve to the oblique line and middle tliird of the 

 posterior face of the tibia. Its tendon is inflected beneath the external malleolus, passes in 

 front below the astragalus, receives the accessory of the long flexor, and then divides into four 

 branches for the four lesser toes. 



3. The posterior tibial, represented by a portion of the peiforans of animals ; its t< ndon is 

 reflected heieath the internal malleolus of the tibia, and is attached to thu scaphoid process. 



4. Tlie proper long flexor of the great toe, also represented by a portion of the perforans. 

 This muscle is voluminous and prismatic, and is attached above to the lower two-thirds of the 

 posterior face of the fibula. Its tendon is reflected inwards on the astragalus and the groove 

 in the os calcis, crosses the tendon of the common long flexor, iiud terminates on the posterior 

 extremity of the third phalanx of the great toe. 



Muscles of the Posterior Foot. 



In Solipeds are found : 1. Tivo lumhrici and tivo interosseous muscles, 

 corresponding to those of the anterior limb. 2. K pedal muscle. 



Pedal Muscle (Extensor Pedis Brevis, Extensor Brevis Digitorum). 



Synonym. — The tarso-prephalangeus of Girard. 



This is a small riband-shaped fasciculus, situated in front of the principal meta- 

 tarsal bone, beneath the extensors of the plialanges. It is attached, by its inferior 

 extremity, to the internal surface of the tendon common to these two muscles, and 

 by its upper extremity to the lower end of the os calcis (and astragalus). It aids 

 in extending the digit (flexing the hock, and probably keeping the teudous tense.) 



Differential Characters in the Muscles op the Posterior Foot in the other Animals. 



A Ruminants. — This is the only muscle in the reirion of the foot met with in Rumi- 

 nants. It is attached, interiorly, to the tendon of the common extensor and that of the proper 

 extensor of the internal digit. 



B. Pig. — This animal possesses : 1. A pedal muscle attached, below, to the two branches of 

 the ciimniou extensor of the large digits. 2. Four interosseous metatarsal muscles, whicli do not 

 appear to diff"er in their general arrangement from tlie metacar})al interosseous muscles. 



C. Carnivora. -In the Dog and Cat there exist in the region of the posterior foot : 



1. A pedal muscle, composed of three fasciculi which have their origin either from the 

 inferior extremity of tlie os caicis, or from the tendinous sheaths in the bend of the hock ; they 

 terminate on the second, third, and fourth digits, by small tendons joined to the branches of 

 the common extensor. 



2 The muscular digitations annexed to the tendon of the perforatus, traces of the fleshy 

 portion of i\w flexor brevis diyitorum of Man. 



3. A flexor pedis accessoriris, or perforans, a small undeveloped muscle commencing outside 

 the tarsus, and terminating by a very delicate aponeurosis on the posterior face of the perforans 

 tendon. 



4. Two or tiiree pale and rudimentary bands, situated inside the tarsus and near the 

 internal digit. Tliese are the vestiges of the muscles proper to the great toe in Man. 



5. An adductor of the litth- toe (abductor minimi digit) is a thin, elongated muscle, carried 

 obliquely from the posterior tarso-metatarsal ligament to the internal side of the first phalanx 

 of that djcrit. 



6. Four interosseous metatarsal muscles, resembling the analogous muscles of the metacarpal 

 region 



7. Lumbrici similar to those of the anterior limb. 



