ANATOMY OF THE ANTHROPOID APES. 195 



(31) Flexor loncjus digitorum pedis. — This muscle arises from the anterior two-thirds 

 of the shaft of the tibia and from the septa between itself and adjacent muscles. Its 

 tendon commences a little way in front of the ankle-joint, but it is covered on the 

 palmar surface with muscle continuously ; the fibres belonging to itself do not end 

 until the commencement of the lumbricales. It divides into three tendons, which 

 supply digits ii., iv., v. 



(32) Flexor Irevis arises from the calcaneum below the aiductor hnllucis; at about 

 the middle of the sole of the foot it gives oiF a delicate muscular slip which ends in a 

 very fine tendon joining i\ie flexor perf or af us of the fourth digit; beyond this it divides 

 into two tendons, of which the outer is the stronger of the two ; this becomes the 

 perforatiis tendon of digit in. At the point where the muscle passes into tendon it is 

 reinforced by a muscular slip from the flexor longus digitorum; it is difficult, therefore, 

 to say whether the tendon belongs to one muscle or the other. The inner tendon of 

 the muscle becomes the perforatus tendon of the index, the perforatus tendon being- 

 furnished, not by the flexor yrofundus, as in the other digits, but by ihe flexor longus 

 digitorum pedis. 



(33) Flexor prof imdus digitorum. — The muscle arises from the upper two- thirds of 

 the shaft of the fibula and from the septa between itself and adjacent muscles ; the 

 tendon becomes quite free from muscular fibres at the ankle. It gives off a strong 

 branch to the thumb, which runs to the distal phalanx of the same ; half an inch 

 beyond this it is joined to the tendon of the flexor longus digitoruin pedis, just in front 

 of the origin of the branch of the latter going to the last digit ; beyond this it divides 

 into two tendons, approximately equal in thickness, which are the perforating tendons 

 of digits III. and iv. 



(34) Lumbricales. — There are three lumbricales. The innermost of these arises 

 from the branch of the tendon of the flexor longus digitorum belonging to th^; index, 

 and from the inner of the two tendons of the deep flexor ; the outermost of the three 

 arises partly from the outer surface of the outer of the two tendons of the deep flexor 

 and partly from the tendon of the flexor longus digitorum supplying the fifth digit. 



(35) Tibialis posticus. — This muscle is the deepest of the three flexor muscles ; it 

 arises from the tibia, from the fibula, from the interosseous membrane, and from the 

 septa between itself and the two remaining flexors ; its tendon of insertion is as large 

 as those of either of the two other flexors ; it is inserted partly on to the ligaments of 

 the sole of the foot lying deep of the long flexor tendon and partly on to the tibia. 



(36) Abductor liallucis arises from the calcaneum and ligaments of the sole of the 

 foot, and is inserted on to the base of the first phalanx of the hallux by a fleshy 

 insertion. 



(37) Abductor minimi digiti arises principally from the calcaneum, but also from the 

 plantar fascia of the foot ; it is inserted by a short tendon on to the base of the first 

 phalanx. 



2f2 



