i THE MUSCLES ON THE BACK OF THE LEG. 309 
the popliteal vessels and tibial nerve between the tibia and fibula; and (3) from 
the oblique line and middle third of the inner border of the tibia. From this 
origin the upper muscular fibres are directed downwards to- join a tendon placed 
on the superficial aspect of the muscle, which is inserted into the tendo Achillis; 
the lower fibres are inserted directly into the tendo Achillis to within one or two 
inches of the os ealcis. 
The muscle is concealed by the gastrocnemius, plantaris, and tendo Achillis in 
nearly its whole extent. It is partially 
superficial on each side of the gastro- 
cnemius and tendo Achillis. The muscle 
covers. the tibialis posticus and the 
flexor muscles of the toes as well as the 
posterior tibial vessels and nerve. 
SEMIMEMBRANOSUS 
TENDON (cut) 
The deep muscles of the back of the 
leg comprise the popliteus, the long 
flexors of the toes, and the tibialis 
W Popliteus fascia 
| 
t) 
/ HHI; (cut) 
Wd 
~ POPLITEUS MUSCLE 
posticus. bial —O 
The popliteus is deeply placed be- = atery 
hind the knee. It arises by a stout 
tendon from a rough impression in front 
of a groove on the outer aspect of the 
external condyle of the femur. This 
tendon passes between the external 
semilunar cartilage and the capsule of * ONS 
the knee-joint, and pierces the posterior 
ligament, from which it takes an ad- 
ditional origin. A bursa is placed be- 
neath the tendon which communicates 
usually with the synovial cavity of the 
knee-joint. The muscle is inserted (1) 
into a triangular surface on the back of prronevs __\ 
the tibia above the oblique line, and (2) —- BREWS 
into the fascia over it (the popliteus 
fascia, derived from the tendon of the 
semimembranosus muscle). The pop- 
liteus is covered at its origin by the 
capsule of the knee-joint. Posteriorly 
it is concealed by the gastrocnemius and 
plantaris muscles, and by the popliteal 
vessels and tibial nerve. Its lower border 
corresponds to the point of bifurcation of 
the popliteal artery and the origin of the 
soleus muscle. 
—= ORIGINS OF SOLEUS 
FLEXOR LONGUS 
DIGITORUM 
TIBIALIS POSTICUS 
FLEXOR LONGUS 
HALLUCIS 
Posterior tibial 
artery and nerve 
The popliteus minor is a small muscle 
attached to the popliteal space of the femur 
and the posterior hgament of the knee-joint. 
Theviexor longus digitorutmwoceds ui sees Bae Gee ee Oe 
pies both the back of the leg and the sole 
of the foot. Its origin is from the posterior surface of the tibia in its middle two- 
fourths, from the fascia over it, and from an intermuscular septa on each side. Its 
tendon, after passing beneath the internal annular ligament, enters the sole of the 
foot, and divides into four subordinate tendons, which are inserted into the four 
outer toes in precisely the same manner as the flexor profundus digitorum in the 
hand. ach tendon enters the digital sheath of the toe, perforates the tendon of 
the flexor brevis digitorum, and is inserted into the base of the terminal phalanx. 
Ligamenta accessoria (longa and brevia) are present as in the hand. Associated 
with this muscle in the sole of the foot are the lumbricales and accessorius. 
= 
