260 



MUSCLES OF THE SOLE OF THE FOOT. 



the great and little toes. This incision should divide the integument and 

 superficial fascia, and both together should be dissected from the deep 

 fascia, as far forward as the base of the phalanges, where they may be re- 

 moved from the foot altogether. The deep fascia should then be removed, 

 and the first layer of muscles will be brought into view. 



The ABDUCTOR POLLICIS lies along the inner border of the foot ; it arises 

 by two heads, between which the tendons of the long flexors, arteries, 

 veins, and nerves enter the sole of the foot. One head arises from the 

 inner tuberosity of the os calcis, the other from the internal annular liga- 

 ment and plantar fascia. Insertion, into the base of the first phalanx of 

 the great toe, and into the internal sesamoid bone. 



Relations. By its superficial surface with the internal portion of the 

 plantar fascia. By its deep surface with the flexor brevis pollicis, musculus 

 accessorius, tendons of the flexor longus digitorum and flexor longus pol- 

 licis, tendons of the tibialis anticus and posticus, the plantar vessels and 

 nerves, and the tarsal bones. On its outer border with the flexor brevis 

 digitorum, from which it is separated by a vertical septum of the plantar 

 fascia. 



Fig. 137.* Th e ABDUCTOR MINIMI DIGITI lies along the outei 



border of the sole, of the foot. It arises from the outer 

 tuberosity of the os calcis, and from the plantar fascia, 

 as far forward as the base of the fifth metatarsal bone, 

 and is inserted into the base of the first phalanx of the 

 little toe. 



Relations. By its superficial surface with the ex- 

 ternal portion of the plantar fascia. By its deep sur- 

 face with the musculus accessorius, flexor brevis 

 minimi digiti, with the tarsal bones, and with the 

 metatarsal bone of the little toe. By its inner side 

 with the flexor brevis digitorum, from which it is se- 

 parated by the vertical septum of the plantar fascia. 



The FLEXOR BREVIS DIGITORUM (perforatus) is 

 placed between the two preceding muscles. It arises 

 from the under surface of the os calcis, from the 

 plantar fascia and intermuscular septa, and is inserted 

 by four tendons into the base of the second phalanx 

 of the four lesser toes. Each tendon divides, pre- 

 viously to its insertion, to give passage to the tendon 

 of the long flexor ; hence its cognomen perforatus. 

 Relations. By its superficial surface with the plantar fascia. By its 

 deep surface with a thin layer of fascia which separates it from the muscu- 

 lus accessorius, tendons of the flexor longus digitorum and flexor longus 

 pollicis, and plantar vessels and nerves. By its borders with the vertical 

 septa of the plantar fascia, which separate the muscle, on the one side 

 from the abductor pollicis, and on the other from the abductor minimi 

 digiti. 



* The third and a part o^ the second layer of muscles of the sole of the foot. 1. The 

 divided edge of the plantar fascia. 2. The musculus accessorius. 3. The tendon of the 

 flexor longus digitorurr 4. The tendon of the flexor longus pollicis. 5. The flexor 

 brevis pollicis. f . The adductor pollicis. Jl. The flexor brevis minimi digiti. 8. The 

 transversus pedis. 9. Interossei muscles, plantar and dorsal. 10. Convex ridge formed 

 by the tendon of the peroneus longus muscle in its oblique course across the foot. 



