The Poot. 387 



tend the second and third phalanges, as seen in walking, 

 where the simultaneous flexion of the first with extension 

 of the second and third phalanges results in the application 

 of the whole length of the toes to the ground. Third 

 layer. The flexor brevis hallucis flexes and slightly ad- 

 ducts the first phalanx of the great toe ; the adductor hal- 

 lucis adducts and flexes the first phalanx of the same toe. 

 This muscle, i.e., the adductor, with the abductor 

 hallucis and the flexor brevis hallucis causes direct 

 flexion of the first phalanx of the great toe, so that, in 

 walking, while the second phalanx is pressed firmly against 

 the ground by the action of the long flexor, these smaller 

 muscles act similarly on the first phalanx. The transversus 

 pedis adducts the first phalanx of the great toe and draws 

 together the heads of the metatarsal bones after they have 

 been separated by the pressure of the weight of the body in 

 walking. The flexor brevis minimi digiti flexes and 

 slightly abducts the first phalanx of the little toe. Fourth 

 layer. The interossei flex the first and extend the ter- 

 minal phalanges, being assisted in these actions by the 

 lumbricales, and, lastly, the plantar interossei adduct 

 the three outer toes, while the dorsal ones abduct the 

 second, third and fourth toes. 



Bloodvessels. The external plantar artery passes 

 obliquely forwards and outwards across the sole of the foot 

 to the base of the fifth metatarsal bone, where it makes a 

 bend forwards and inwards, to sink deeply into the foot 

 and terminate at the proximal end of the first interosseous 

 space, by anastomosing with the communicating branch 

 from the dorsalis pedis. It has two venae comites. The 

 internal calcanean branches of the external plantar arise 

 close to the origin of the vessel (occasionally they are 

 derived from the posterior tibia!, close to its bifurcation), 

 and are of great importance in connection with the line of 



