SOLE OF THE FOOT 303 



phalangeal ligaments of the third, fourth, and fifth toes, and 

 proceeds transversely medially, under cover of the flexor 

 tendons, to find insertion into the lateral side of the base of 

 the proximal phalanx of the great toe, in common with the 

 oblique head. Its nerve of supply comes from the deep 

 division of the lateral plantar nerve. 



Flexor Brevis Digit! Quinti (O.T. Flexor Brevis Minimi 

 Digiti). The flexor brevis digiti quinti is a single fleshy slip, 

 which springs from the base of the fifth metatarsal bone and 

 the sheath of the peronaeus longus tendon. It is inserted into 

 the lateral side of the base of the proximal phalanx of the 

 little toe. Its nerve of supply comes from the superficial 

 division of the lateral plantar nerve. 



Dissection. The oblique head of the adductor hallucis and the flexor 

 hallucis brevis must now be detached from their origins and thrown 

 forwards, in order that the entire length of the plantar arterial arch, and 

 the deep division of the lateral plantar nerve, may be displayed. In 

 raising the oblique head of the adductor hallucis the branch which is given 

 to it by the deep division of the lateral plantar nerve must be secured and 

 retained. 



Arcus Plantaris (Plantar Arch). The plantar arterial 

 arch is the continuation of the lateral plantar artery across 

 the sole of the foot. It runs from the base of the fifth 

 metatarsal bone to the base of the first interosseous space, 

 where it is joined by the terminal plantar portion of the 

 dorsalis pedis artery. The arch is deeply placed ; it rests 

 against the interosseous muscles close to the proximal ends 

 of the metatarsal bones, and it is concealed by the flexor 

 tendons, the lumbrical muscles, and the oblique head of 

 the adductor hallucis. It is accompanied by the deep 

 division of the lateral plantar nerve and by two venae comites. 



The branches which proceed from the arch are : 



1. Articular. 



2. Posterior perforating. 



3. Second, third, and fourth plantar metatarsal arteries. 



4. Plantar digital artery to the lateral side of the little toe. 



The articular branches rise from the concavity of the arch, 

 and run posteriorly to supply the tarsal joints. 



The posterior perforating branches are three in number. 

 They pass dorsally through the posterior ends of the three 

 lateral intermetatarsal spaces and between the heads of the 

 corresponding dorsal interosseous muscles. Each ends on the 



