MUSCLES OF THE POSTERIOR /,/.!//;>. 309 



II. 1'osterior Tibial Region. 



MINANTS.- In tin- Of, Sheep, and Goat, the mu.-eular ]>ortion of the perforatus ia 

 thicker ti an in Soliped.s. The [nation of tlie perforuns is better defined than in Solipeds, 

 and is lodged in a depression mi the principal portion; it can easily be traved from the 

 tsiijH -M-exti -rnal surface of tlie tibia, where it originates. The tendon does not ditl'er from 

 tliat in the fon-limit ; but the bunds whieli descend from the metatarsus to t'ie heels, to 

 In unit. .1 \\ itli the two terminal branches of this tendon, are much smaller tha-i those in 

 the metacarpal region. 



I'AKMVOHA. The soleus is absent in the Dog and Cut. The muscular body of the 

 perforatus is prismatic, voluminous, and entirely blended, in its upper two-thinU at least, 

 with thi' external u;a>trocneniius; these two muscles have therefore common origin. The 

 tendon is quadrifurcatcd, as in the anterior limb: it otters on its surface, shortly before 

 its division, several thin muscular bands, traces of the fleshy portion of tile common short 

 musi-le of Man. Several of these bands come from the perfumm tendon, and all pass to 

 tin four ii rininal branches of tlie muacle. The terminal tendon of the perforans is divided 

 into four or five branches, one for each digit. 



The potterior tibial is not united inferiorly to this tendon, but constitutes a perfectly 

 distinct muscle situated between the deep and oblique flexors of the phalanges. Formed 

 by a very small fleshy body and a long thin tendon, this mus.dc originates above the 

 peroneus, from the posterior surface of the tibin. Its tendon lies betide that of the 

 oblique flexor, and with it enters the groove behind and within the inferior extremity of 

 tin- tibia. Enveloped by a synovial membrane proper to its passage through this groove, 

 this tendon soon leaves it lo pass to the free surface of the posterior turso-metatarsal 

 ligament, with which it is blended towards the middle of the tarsus. 



COMPARISON OF THE MUSCLES OP THE LEG OF MAN WITH THOSE OF ANIMALS. 



In Man, the muscles of the leg are divided into three regions: an anterior, external, 

 and jxjsterior. 



A. Anterior Region. 



This includes three muscles : 



1. The anterior tibial, which corresponds to the fleshy portion of the flexor of the 

 metatarsus, and whose im[>erforate tendon is fixed into the first cuneiform. 



J. The common long extensor of the toes, which represents the anterior extensor o the 



phalanx of the Horse. This muscle is attached, above, to tlie external tnU'rosity of the 



tibia and tlie upper three-fourths of the inner lace of the fibula; its tendon divides into 



lli tlie internal of which furnishes a branch to the second, third, and fourth 



toes, and the external goes to the tilth. 



The froptr extensor of the large toe, represented in the Dog by a small fasciculus 

 lileiidid with the anterior tibial, is an elongated semi-pi-nniform muscle which 

 limn the inner face of the fibula and the intcrosseous ligament, and terminates on the 

 1 phalanx of the great toe, after receiving the pedal tendon 'extensor brevis 

 digitvrum). 



B. External Region. 



This region is only composed of two muscles : the long and nhort peroneus. 



r.tt, whieh does not exist in Solipeds, is a p uniform muscle attached to tlie 

 upl- r third of the fibula, the external tul n-iiy of the tibia, and tne internal f:uv of the 

 tii'ial aponeurosis, by the su|N-ri<>r extremities of its muscular fibres. Tlie il;,t tendon 

 which terminates it is fixed to the outer portion of the base of the tii>t imtatarsal. 



The second corresponds to the laU-rul exten.-<>r of the phalan-es of the llors.-, and ia 

 found in iill animals. It is penniform, and is uttaclud above, by its fleshy fibres, to the 

 lower two-thiid.- ..f the external face of the fibula; below, by its tendon, to the upper 

 ity of tl.e fifth mctatarsal. 



Theoe two muscles determine very complicated movements in the region of tlie foot 



C. Posterior Region. 



Interior tibial nni.-rles form two layers: a superficial and a deep. 

 Tlie tir^t e,.mpii-e- tin <-nirnl triccp and the i>lnntari*. The triceps r 



