248 ANATOMY OF THE LOWER EXTREMITY. 



of the third and fourth metatarsal bones, and from the 

 sheath of the tendon of the peroneus longus muscle ; it 

 forms a short belly, and is inserted, with the inner head of 

 the flexor brevis pollicis, into the base of the first phalanx 

 of the great toe. A sesamoid bone is usually found in the 

 insertion of its tendon. 



The FLEXOR BREVIS MINIMI DIGITI PEDIS arises from 

 the base of the metatarsal bone of the fifth toe and the 

 sheath of the tendon of the peroneus longus, and is inserted 

 into the base of the first phalanx of the little toe. 



The TRANSVERSALIS PEDIS is a thin layer of muscular 

 slips, lying transversely across the anterior portions of the 

 metatarsal bones ; it arises from the heads of the metatar- 

 sal bones of the four lesser toes, and is inserted into the 

 tendon of the adductor pollicis ; sometimes there is but 

 one slip ; there are rarely so many as four. 



The adductor pollicis and flexor brevis minimi digiti are to be di- 

 vided near their origins, and turned forward on to the toes ; this will 

 expose the plantar arch. 



The plantar arch is the continuation of the external 

 plantar artery from the base of the fifth metatarsal bone 

 to its anastomosis with the communicating branch of the 

 dorsalis pedis ; it lies upon the interosseous muscles, and 

 gives off four digital branches to the toes; the first goes to 

 the outer side of the little toe ; the others, dividing at the 

 commissures, supply the contiguous sides of the outer 

 three toes and the outer side of the second. At each end 

 of the interosseous spaces, the digital arteries send small 

 branches called posterior and anterior perforating, to the 

 interosseous branches of the dorsalis pedis artery. The 

 communicating branch of the dorsalis pedis enters the sole 

 of the foot, and, uniting with the internal plantar artery 

 and the termination of the plantar arch, gives off the branch 

 which supplies both sides of the great toe. 



The PLANTAR INTEROSSEOUS MUSCLES are three in num- 

 ber; they arise from the under sides of the metatarsal 

 bones, and are inserted into the inner sides of the bases of 

 the first 'phalanges of the outer three toes, and into the 

 expansions of the extensor tendons. 



The tendon of the tibialis posticus (p^244) may now be 

 traced to its termination ; it passes forward over the articu- 

 lation of the astragalus and scaphoid bones to be inserted 

 into the latter, into the base of the first metatarsal bone, 



