THE LOWER EXTREMITY, POSTERIOR. 637 



Insertion. By four tendons into the bases of the second 

 phalanges of the four smaller toes. The tendons of the 

 brevis divide for the passage of the tendons of the flexor 

 longus digitorum, then reunite, forming a buttonhole for 

 the passage of the tendons of the flexor longus digitorum, 

 they then again divide and pass to their insertion into the 

 bases of the second phalanges. 



Nerve Supply. The internal plantar. 



Action. To flex the four outer toes, beginning at the 

 second phalanges, to flex the bones of the foot and pre- 

 serve the arch. 



Abductor Hallucis (Pollicis). Fig. 133. 



Origin. From the inner margin of the greater tubercle 

 of the os calcis, the deep part of the internal annular liga- 

 ment, the side of the intermuscular septum, and from the 

 deep surface of the plantar fascia covering it. 



Insertion. Into the inner margin of the base of the first 

 phalanx of the great toe. 



The tendon of this muscle is joined before its insertion 

 by the inner half of the tendon of the flexor brevis hallucis. 



Beneath the origin of the muscle is a fibrous arch which 

 reaches from the internal intermuscular septum to the deep 

 ligamentous structures at the inner border of the foot, and 

 through which pass the plantar vessels and nerves. 



Nerve Supply. The internal plantar. 



Action. To abduct the great toe from the middle line 

 of the foot (passes through the middle of the second toe), 

 to flex the first phalanx of the great toe, to preserve the 

 arch of the foot. 



Abductor Minimi Dig-iti. Fig. 133. 

 Origin. From the under surface of the os calcis in front 

 of both tuberosities, from the side of the external intermus- 



