638 A MANUAL OF ANATOMY. 



cular septum, and from the deep surface of the band reach- 

 ing from the outer side of the os calcis (the lesser tuberos- 

 ity) to the base of the fifth metatarsal bone. 



Insertion. The outer side of the base of the first phalanx 

 of the little toe, the outer side of the base of the fifth meta- 

 tarsal bone. 



Nerve Supply. The external plantar. 



Action. To abduct the little toe from the middle line of 

 the foot, to flex the first phalanx of the little toe. (Abduc- 

 tion of the first phalanx carries with it the rest of the pha- 

 langes, but flexion is only of the first phalanx). 



The Internal Plantar Nerve. Figs. 132, 133. 



This is larger than the external plantar. It is accom- 

 panied by the corresponding artery for a part of its course. 



It runs forward between the abductor hallucis and the 

 flexor brevis digitorum muscles and ends at the middle of 

 the foot by dividing into three (or four) digital branches. 

 These are named from within outward. 



(i) The first digital branch supplies a muscular branch to 

 the flexor brevis hallucis and cutaneous branches to the 

 inner side of the great toe. (2) The second sends a mus- 

 cular branch to the first lumbricalis, then bifurcates to sup- 

 ply the adjacent sides of the first and second toes. (3) The 

 third supplies the second lumbricalis, and the contiguous 

 sides of the second and third toes. (4) The fourth ; this 

 communicates with the superficial division of the external 

 plantar nerve, and supplies the opposite sides of the third 

 and fourth toes. The digital nerves supply the joints of 

 the toes which they pass over. Their branches to the toes 

 after their bifurcation are called collateral digital nerves. 

 There are six digital and ten collateral digital nerves, the 

 internal plantar furnishing four of the digital and seven 



