386 Anatomy Applied to Medicine and Sutgeiy. 



nerve which lies in the superficial tissues. In tying the 

 artery, the needle should be passed from the outer side of 

 the vessel to avoid the nerve. 



Plantar Surface. In the sole of the foot the ner- 

 vous supply of the superficial structures consists in the 

 internal and the external plantar nerves with the plantar 

 cutaneous branches from the posterior tibial. Beneath 

 the superficial fascia is the plantar fascia, which is com- 

 posed of three parts a central and two lateral. The cen- 

 tral portion of this fascia is attached, behind, to the inner 

 tubercle of the os calcis, while, in front, it divides, near the 

 heads of the metatarsal bones, into a process for each toe. 

 This process sends superficial fibres, as in the palmar fas- 

 cia, to the overlying integument, while the main part of 

 each process blends with the fibrous sheath for the toe, 

 and forms, therefore, a channel for the passage of the 

 flexor tendon to the last phalanx. The outer portion of the 

 fascia is attached to the os calcis behind, and spreads for- 

 wards, covering the abductor minimi digiti, to be attached 

 to the base of the fifth metatarsal bone ; while the inner 

 portion of the fascia, attached behind to the internal an- 

 nular ligament, covers the abductor hallucis muscle. Be- 

 neath this plantar fascia, the muscles of the sole are ar- 

 ranged in four layers and have actions as follows : First 

 layer. The abductor hallucis flexes and abducts the first 

 phalanx of the great toe ; the flexor brevis digit orum flexes 

 the second phalanges and, in combination with the long 

 flexor, assists in walking, by pressing the toes against the 

 ground ; the abductor minimi digiti abducts and flexes the 

 little toe. Second layer. The flexor accessorius assists 

 in flexing the last phalanges of the four outer toes, at the 

 same time drawing them outwards, thus neutralizing the 

 inward traction exercised by the long flexor. The lum- 

 bricales, four in number, flex the first phalanges and ex- 



