56o A MANUAL OF ANATOMY 



with the median nerve in the hand. There is this difference, however, between 

 these two nerves : the internal plantar has one single digital nerve and three 

 compound digital nerves, whereas the median has three single digital nerves 

 and two which are compound. 



External Plantar Nerve. — This nerve has a more hmited cutaneous, 

 but a wider muscular, distribution than the internal plantar. From 

 its origin it is directed forwards and outwards to the base of the 

 fifth metatarsal bone, where it breaks up into two divisions, super- 

 ficial and deep. In this course it lies at first between the flexor 

 brevis digitorum and flexor or musculus accessorius, and subse- 

 quently in the groove between the former muscle and the abductor 

 minimi digiti. It is close to the inner side of the external plantar 

 artery, and occupies the concavity of the curve described by that 

 vessel. This part of the nerve is spoken of as the trunk. 



Branches of the Trunk. — The branches are as follows : muscular 

 to the flexor or musculus accessorius and abductor minimi digiti ; 

 articular to the calcaneo-cuboid articulation ; cutaneous to the 

 integument of the outer half of the sole ; and terminal. 



The terminal branches are two in number, superficial and deep, 

 and they spring from the trunk at the base of the fifth metatarsal 

 bone. 



The superficial division furnishes two digital nerves, outer and 

 inner. The outer digital nerve is single, and is distributed to the 

 outer side of the little toe, supplying branches to the flexor brevis 

 minimi digiti and, as a general rule, to the interosseous muscles 

 of the fourth interosseous space, namely, the fourth dorsal and 

 the third plantar. It may, however, fail to supply these two 

 interosseous muscles, in which case they derive their nerve-supply 

 from the deep division of the external plantar nerve. The inner 

 digital nerve is compound. In its forward course it communicates 

 by a twig with the most extegrnal digital branch of the internal 

 plantar nerve which supplies the contiguous sides of the third and 

 fourth toes, and near the cleft between the fourth and fifth toes it 

 divides into two collateral plantar digital nerves, which supply the 

 contiguous sides of these two toes. The digital branches of the 

 superficial division of the external plantar nerve resemble in all 

 respects those of the internal plantar. 



The deep division is muscular and articular in its distribution. 

 It sinks deeply into the sole with the external plantar artery as 

 that vessel forms the plantar arch. Its direction is inwards and 

 forwards on the deep or superior surface of the musculus acces- 

 sorius, long flexor tendons and lumbricales, and adductor obliquus 

 hallucis, and lying upon the bases of the second, third, and fourth 

 metatarsal bones. 



Branches. — The branches of the deep division are muscular, 

 articular, and perforating. 



The muscular branches supj)ly (i) the interosseous muscles, 

 plantar and dorsal, with the exception, as a general rule, of the 

 two which occupy the fourth interosseous space, namely, the 



