aT 
beneath the internal annular ligament and abductor hallucis to the interval between 
that muscle and the flexor brevis digitorum, in company with the internal plantar 
artery. 
The collateral branches are muscular, cutaneous, and articular. The muscular 
branches supply the abductor hallucis and the flexor brevis digitorum. The plantar 
cutaneous branches are small twigs which pierce the plantar fascia in the interval 
between these muscles to supply the inner part of the sole of the foot. The arti- 
cular branches are minute twigs which supply the inner tarsal and tarso-metatarsal 
articulations. 
The terminal branches are four in number, and may be designated first, 
second, third, and fourth, from within outwards. 
The first (most internal) branch separates from the nerve before the others, 
and pierces the plantar fascia behind the ball of the great 
toe. It supplies a muscular branch to the flexor brevis 
hallucis, and cutaneous branches to the inner side of the 
foot and ball of the great toe. It terminates as the 
plantar digital nerve for the inner side of the great toe. 
The second branch arises along with the third and 
fourth ; after supplying a branch to the first lumbrical 
muscle, it becomes superficial in the interval between the 
first and second toes, and terminates by dividing into two 
plantar digital nerves for the supply of the adjacent sides 
of these toes. 
The third and fourth branches are entirely cutaneous in 
their distribution. They become superficial in the intervals 
between the second and third and the third and fourth 
toes respectively, and there divide into plantar digital 
branches for the supply of the adjacent sides of these toes. 
™} The plantar digital nerves supply the whole length of 
the toes on the plantar aspect, and, in relation to the 
terminal phalanges, furnish minute dorsal offsets for the 
supply of the nails and tips of the toes on their dorsal 
surface. The internal plantar nerve thus supplies the skin 
of the three and a half inner toes in the sole of the foot 
612 THE NERVOUS SYSTEM. 
Fic. 445.—ScHEME oF DIstRI- : : 
BUTION OF THE Prantar and four muscles: the abductor hallucis and flexor brevis 
NERVES. 
digitorum, the flexor brevis hallucis, and the first lumbrical 
I.Pl, Internal plantar nerve, and yuscele. 
its cutaneous and muscular 
branches ; F.B.D, Flexor 
brevis digitorum; Abd.H, 
Abductor hallucis ; F.B.H, The external plantar nerve (n. plantaris lateralis) 
Flexor brevis hallucis ; L.I, 
First lumbricalis: E.Pl, Ex. 18 homologous with the ulnar nerve in the hand. From 
its origin beneath the internal annular ligament it 
extends forwards and outwards in the sole, in company 
with the external plantar artery, between the flexor brevis 
EXTERNAL PLANTAR NERVE. 
ternal plantar nerve, and its 
cutaneous and muscular 
branches ; Ace, Accessorius ; 
Abd.m.d, Abductor minimi 
digiti; F.B.M.D, Flexor brevis 
minimi digiti; R.P, Ramus 
profundus, 
digitorum and accessorius muscles, towards the head of 
the fifth metatarsal bone. Here it terminates by dividing 
into superficial and deep branches. 
Collateral Branches.— Muscular branches are given off from the undivided nerve 
to the accessorius and abductor minimi digiti muscles. Cutaneous branches 
pierce the plantar fascia at intervals along the line of the intermuscular septum, 
between the flexor brevis digitorum and abductor minini digiti. 
Terminal Branches.—The superficial branch (r. superficialis) is mainly cutaneous. 
Passing forwards between the flexor brevis digitorum and abductor minimi digiti, 
it divides into external and internal parts. 
The external branch, after supplying the flexor brevis minimi digiti muscle, and 
sometimes one or both interossei of the fourth space, becomes superficial behind 
the ball of the little toe, and supplies cutaneous twigs to the sole of the foot and 
ball of the toe. It terminates as the plantar digital branch for the outer side of 
the little toe. 
