ACTION OF MUSCLES OF THE FOOT. 245 



Relations. By its superficial surface with the tendons of the flexor 

 longus and flexor brevis digitorum, and the lumbricales. By its 

 deep surface with the interossei, and heads of the metatarsal bones. 



Fourth Layer. 

 Interossei plantares. 



The Plantar interossei muscles are three in number, and are 

 placed upon rather than between the metatarsal bones. They arise 

 from the base of the metatarsal bones of the three outer toes, and 

 are inserted into the inner side of the extensor tendon and base of 

 the first phalanx of the same toes. In their action they are all 

 adductors. 



Relations. By their superficial surface with the dorsal interossei 

 and the metatarsal bones. By their deep surface with the external 

 plantar artery and veins with their branches, the adductor pollicis, 

 transversus pedis, and flexor minimi digiti. 



Actions. All the preceding muscles act upon the toes ; and the 

 movements which they are capable of executing may be referred to 

 four heads, viz. flexion, extension, adduction, and abduction. In 

 these actions they are grouped in the following manner : 



Flexion. Extension. 



Flexor longus digitorum, Extensor longus digitorum, 



Flexor brevis digitorum, Extensor brevis digitorum. 



Flexor accessorius, 

 Flexor minimi digiti. 



Adduction. Abduction. 



j . . ( one dorsal, Interossei, three dorsal, 



lj j three plantar. Abductor minimi digiti. 



The great toe, like the thumb in the hand, enjoys an independent 

 action, and is provided with distinct muscles to perform its move- 

 ments. These movements are precisely the same as those of the 

 other toes, viz. : 



Flexion. Extension. 



Flexor longus pollicis, Extensor proprius pollicis, 



Flexor brevis pollicis, Extensor brevis digitorum. 



Adduction. Abduction. 



Adductor pollicis. Abductor pollicis. 



The only muscles excluded from this table are the lumbricales, 

 four small muscles, which from their attachments to the tendons of 

 the long flexor, appear to be assistants to their action ; and the 

 transversus pedis, a small muscle placed transversely in the foot 

 across the hads of the metatarsal bones, which has for its office 

 the drawing together of the toes. 



