158 ANATOMY IN A NUTSHELL. 



[nsertion. — (Plato LIU.) — Innermost tendon into dorsal surface of base 

 of first phalanx of great toe; the other three into outer sides of long extensor 

 tendons of second, third and fourth toes. 



Action. Extends phalanges of four inner toes acting only on first phalanx 

 of ilif great toe. 



N i kve Supply.— Anterior tibial. 



Blood Supply. — Dorsalis pedis. 



Abductor hallucis.— Description. — (Plate LV.) — This muscle is the inner 

 one "t' the three muscles of the first layer of the plantar surface of the foot. It 

 is protected by the plantar fascia. This fascia is beneath the muscle when one's 

 fool is on the floor. 



Origin.- (Plate LI 11.) — (1) Inner tubercle of under surface of os calcis;(2) 

 internal annular ligament; (3) plantar fascia; (4) intermuscular septum. 



Insertion. — (Plate LIII.) — Inner side of base of first phalanx of greattoe. 



Actiox. — Abducts great toe; flexes proximal phalanx. 



Nerve Supply. — Internal plantar. 



Blood Supply. — Internal plantar. 



Abductor minimi digiti. — Description. — (Plate LV.) — This muscle is 

 separated from the Flexor brevis digitorum by a vertical septum of fascia, and 

 has along its inner border the plantar vessels and nerve. All the muscles of the 

 first Layer of the foot bear the same relation to the plantar fascia. 



Origin. — (Plate LIII.) — (1) Outer tubercle of os calcis; (2) under surface 

 of os calcic in front of both tubercles; (3) fore part of inner tubercle; (4) plantar 

 fascia: (5) intermsucular septum. 



Insertion. — (Plate LIII.) — Its tendon, after gliding over a smooth facet 

 on the under surface of the base of the fifth metatarsal bone, is inserted, together 

 with the short Plexor of the little toe, into the outer side of base of first phalanx 

 of little toe. 



Action. — Abducts little toe; flexes proximal phalanx. 



Nerve Supply. — External plantar. 



Blood Supply. — External plantar. 



Flexor brevis digitorum. — (Perforatus.) — Description. — (Plate LV.) — This 

 muscle is called Perforatus because its tendons are perforated by those of the 

 Flexor longus digitorum (Perforans.) After the muscle divides into four 

 tendons, one for cadi of the four outer toes, these tendons themselves divide 

 opposite bases of the first phalanges for the passage of the tendons of the Flexor 

 longus digitorum. They divide a second time to be inserted into the sides of 

 the second phalanx of the four outer toes. This muscle is separated from the 

 externa] plantar vessels and nerve by a thin layer of fascia. 



ORIGIN. (Plate bill.)— (1) Inner tubercle of os calcis; (2) central part 

 of plant a i- fascia; (3) intermuscular septa. 



Insertion.- (Plate LIII.) Sides of second phalanges of four lesser toes. 



\ii [on. Flexes toes. 



\i:i;\ i: Supply. Internal plantar. 



P>!.(»oi> SUPPLY.- Plantar arteries. 



Adductor obliquus hallucis.- Description. — (Plate LX.) — This muscle 



