364 MR. J. BESWICK PERRIN ON THE 
inserted by a slender tendon, which passes beneath the anterior annular ligament into 
the fibular side of the base of the innermost metatarsal bone. 
The extensor longus hallucis (Pl. LXV. fig. 2) is closely associated with the pre- 
ceding muscle. It arises by a pointed tendinous process from the outer aspect of the 
head of the tibia. It is fusiform in shape, and terminates in a slender tendon which 
passes underneath the annular ligament with the tendon of the preceding muscle, and is 
inserted by its side into the base of the inner metatarsal bone and shaft. 
The extensor longus digitorum (Pl. LXV. fig. 1, 2) is situated behind and on a deeper 
plane than the tibialis anticus. It springs from the upper and anterior half of the tibia, 
also from its head and median tubercle. An inch above the ankle-joint it terminates in 
a slender tendon which passes underneath the anterior annular ligament, traverses the 
metatarsus as a single tendon as far as the phalangeal bases, where it undergoes an 
increase in size, and then divides into three tendons, which are distributed to the three 
outer digits. The middle one is the longest and strongest tendon. All pass to the 
bases of the distal phalanges. Opposite the ankle-joint the tendon passes through the 
tibial intertrochlear groove, and then crosses behind the tendons of the tibialis anticus 
and extensor proprius hallucis. 
The extensor brevis digitorum (Pl. LXV. fig. 2,11, 12) is a powerful muscle consisting 
of an outer and an inner portion. The outer arises from the whole length of the dorsal 
aspect of the outer metatarsal bone, and from the proximal third of the external surface 
of the inner metatarsal. Opposite the distal extremities of the metatarsals it divides 
into two short tendons, which pass to be inserted into the dorsal aspect of the bases of 
the first phalanges of the 2nd and Srd digits. The imner portion arises by a pointed 
process from the inner metatarsal bone. It terminates in a single tendon, which 
is inserted into the base of the first phalanx of the 2nd digit, more internal than the 
preceding. 
This muscle partakes more of the character of an interosseous than a legitimate 
extensor brevis digitorum. 
On the tibial side of the extensor brevis are two other muscles—a long, and a short 
one. The long one arises from the base of the inner metatarsal bone by fleshy fibres. 
It terminates opposite the lower third of the metatarsus in a moderately strong tendon, 
which passes obliquely forwards to the extensor aspect, as far as the base of the distal 
phalanx. It is the only long extensor tendon to this digit. The short muscle arises 
from the lower half of the tibial side of the inner metatarsal bone, and is inserted into 
the base of its first phalanx on its extensor aspect. The position of this digit is exactly 
the reverse of that of the 2nd, 3rd, and 4th digits. 
The rudimentary aponeurotic plantar expansion, analogous to the plantar fascie, sends 
a slip to the tibial side of the base of the first phalanx superficial to the preceding 
muscle. 
On the outer side of the Ist digit is a small opponens muscle (interosseus). It arises 
