396 
a strong tendon which passes over the dorsum of the foot, to be inserted into the 
internal cuneiform and the base of the first metatarsal bone. 
THE MUSCULAR SYSTEM. 
The muscle is superficially placed along the outer side and front of the tibia, 
internal to the long extensors of the toes and the anterior tibial vessels and nerve. 
Its tendon occupies special compartments beneath both upper and lower parts of 
PERONEUS 
LONGUS 
TIBIALIS 
ANTICUS 
PERONEUS BREVIS PROPRIUS 
HALLUCIS 
Upper 
portion of 
anterior 
annular 
ligament 
Lower portion of 
anterior annular 
ligament 
TENDON OF PERONEUS 
TERTIUS 
INNERMOST SLIP OF 
EXTENSOR BREVIS /¥, 
DIGITORUM | 
Fic. 261.—MuscLES OF THE FRONT OF THE 
RicHt Leg AND DoRSUM OF THE Foot. 
and for a corresponding extent from the interosseous membrane. 
the anterior annular ligament, enclosed in a 
separate synovial sac. 
The tibio-fascialis anticus is a separated portion 
of the muscle occasionally present, inserted into the 
fascia on the dorsum of the foot. 
The extensor longus digitorum arises 
from the outer side of the external tuberosity 
of the tibia, from the upper two-thirds or more 
of the anterior surface of the fibula, from the 
fascia over it, and from intermuscular septa on 
either side. It gives rise to a tendon which 
passes beneath the anterior annular lhgament, 
and in front of the ankle divides into four 
tendons, inserted into the four outer toes, 
exactly in the same way as the corresponding 
tendons in the hand (see p. 330). They form 
membranous expansions on the dorsum of the 
first phalanx, joined by the tendons of the 
extensor brevis digitorum, lumbricales, and 
interossei, which separate into one central and 
two lateral slips, attached respectively to the 
middle and terminal phalanges. 
The muscle is superficial, and is placed 
external to the tibialis anticus and extensor 
proprius hallucis, and internal to the peronei 
muscles. The musculo-cutaneous nerve is on 
its outer side. It conceals the anterior tibial 
vessels and nerve. The tendon occupies a 
separate compartment along with the peroneus 
tertius beneath the lower part of the anterior 
annular ligament, invested by a special synovial 
membrane. 
The peroneus tertius is a separated por- 
tion of the extensor longus digitorum. It is 
an essentially human muscle. It arises (in- 
separably from the extensor longus digitorum) 
from the anterior surface of the fibula, and 
from the intermuscular septum external to it. 
The tendon of the muscle is inserted into the 
dorsal aspect of the base of the fifth metatarsal 
bone. It accompanies the extensor longus 
digitorum beneath. the anterior annular liga- 
ment, and lies external to that muscle on the 
dorsum of the foot. 
The extensor proprius hallucis muscle 
(m. extensor hallucis longus) arises from the 
front of the fibula in its middle three-fifths, 
Its tendon 
passes over the dorsum of the foot, to be inserted into the base of the terminal 
phalanx of the great toe. 
In the leg the muscle is deeply placed between the 
tibialis anticus and extensor longus digitorum. 
It conceals the anterior tibial 
vessels and nerve, and crosses the termination of the anterior tibial artery in front 
of the ankle joint. 
It is invested by a special synovial sac as it lies beneath the 
