294 INFERIOR EXTREMITY 



in slender tendons for the four lateral toes. These enter the 

 fibrous flexor sheaths of the toes, and will be afterwards 

 studied. The flexor digitorum brevis is supplied by the 

 medial plantar nerve. 



M. Abductor Hallucis. The abductor hallucis takes origin 

 from the medial aspect of the medial tubercle of the calcaneus, 

 from the medial intermuscular septum, from the distal border 

 of the ligamentum laciniatum, and from the medial part of the 

 plantar aponeurosis which covers it. A strong tendon issues 

 from the fleshy belly. This is joined, on its lateral and deep 

 surface, by fibres of the medial head of the flexor hallucis 

 brevis, and it is inserted into the medial aspect of the base of 

 the proximal phalanx of the great toe. The abductor hallucis 

 is supplied by the medial plantar nerve. 



M. Abductor Digit! Quinti (O.T. Abductor Minimi Digiti). 

 The origin of this muscle extends medially under cover of 

 the flexor digitorum brevis. The latter muscle must there- 

 fore be detached from the calcaneus and turned forwards. 

 The abductor digiti quinti is then seen to have a broad 

 origin from both the medial and lateral tubercles of the 

 calcaneus, from the lateral intermuscular septum, and the lateral 

 part of the plantar aponeurosis which covers it. Its tendon 

 is inserted into the lateral aspect of the base of the proximal 

 phalanx of the little toe. The abductor digiti quinti is 

 supplied by the lateral plantar nerve. 



Dissection. The origin of the abductor hallucis from the calcaneus and 

 from the ligamentum laciniatum should be divided and the muscle turned 

 medially. With a little dissection the mode and place of origin of the 

 plantar arteries and nerves will be made manifest. They are the terminal 

 branches of the posterior tibial artery and tibial nerve, and they arise in the 

 hollow of the calcaneus under cover of the origin of the abductor hallucis. 

 But further, the lateral plantar artery and nerve may now be traced as 

 they pass laterally upon the quadratus plants to the point where they 

 were first seen viz. in the interval between the abductor digiti quinti 

 and the flexor digitorum brevis. In following the lateral plantar nerve, 

 the branches which it gives to the quadrate plantar muscle and the abductor 

 digiti quinti must be secured. The latter nerve lies close to the tubercle 

 of the calcaneus. 



Art. Plantaris Medialis (O.T. Internal Plantar Artery). 

 This is the smaller of the two terminal branches of the 

 posterior .tibial artery. It arises in the hollow between the 

 medial malleolus and the prominence of the calcaneus, at 

 or proximal to the distal border of the ligamentum laciniatum. 

 At first it is placed under cover of the abductor hallucis, but 



