60 ANATOMY OF VERTEBRATES. 



fihular flexor now becomes the ' flexor longus hallucis,' and con- 

 centrates its force exclusively on the tendon, 2, 2c, which goes 

 to the last phalanx of the hallux, z; this tendon is twice the size 

 of any of the divisions of that of the long flexor on the tibial side. 

 This is limited to the function implied by the name 'flexor longus 

 digitorum pedis,' its tendon, fig. 27, i, sending off successively the 

 perforating tendons to the second, third, fourth, and fifth toes. In 

 fig. 27, are shown the insertion of the 'tibialis posticus,' 15; the 

 'flexor brevis minimi digiti,' 7 ; the ( flexor brevis pollicis,' inserted 

 into the outer, 9, and inner, 10, sesamoids, the adductor pollicis, 8, 

 and the peculiar ( transversalis pcdis,' 10, arising from the under 

 surface of the distal and of the fifth metatarsal, crossing three of 

 the other metatarsals, to be inserted into the outer side of the 

 proximal phalanx of the hallux, blending there with that of the 

 e adductor pollicis.' 



The heel being the lever-power by which the whole superincum- 

 bent weight of the body is raised in the peculiar ' walk,' or bipedal 

 gait, of Man, muscles that are distinct in quadrupeds are here, 

 contrary to ordinary rule, blended, or have a common insertion. 

 Not only the outer and inner gastrocnemius, but the soleus, and 

 even the plantaris, might be regarded as so many origins of the 

 same muscle, which combine and concentrate their forces upon 

 the calcaneum. 



The f panniculus carnosus' of quadrupeds is reduced in Bimana 

 to the f platysma myoides,' fig. 28, p, p, p, which extends from 

 the upper and fore part of the chest upward over the front and 

 side of the neck to the mandible and lower part of the face, where 

 the two muscles meet below the symphysis. The middle fibres 

 are attached to the base of the jaw, and posteriorly ascend to the 

 fascia of the masseter ; the anterior ones ascend with the depressor 

 anguli oris and quadratus mexiti to the lower lip and angle of the 

 mouth. In many instances there is a strip from the parotid fascia 

 which converges to this angle, and constitutes the ( risorius san- 

 torini.' The platysma draws down the lower part of the face, or, 

 by a slighter action, the lower lip : the ' risorial ' slip tends to 

 raise the angle of the mouth. Most of the muscles of the face 

 are attached at one part to bone, at another to skin or to some other 

 muscle. The skin of the human face is remarkable for its tenuity, 

 flexibility, and abundant supply of vessels and nerves; its vascu- 

 larity tinting the cheeks and lips : it is more adherent and the 

 subjacent cellular tissue is denser along the median line than at 

 other parts. 



The ' orbicularis oris,' fig. 29, o o, has no attachment to bone. 



