Zhang et at. • CHINESE GROUSE MYOLOGY 
333 
the femur. The caudal surface of the belly is 
strongly attached to the pars accessoria of M. 
lienor cruris lateralis. The belly is rounded 
proxiraally. and separated by the insertion tendon 
ofM. flexor cruris medialis from the belly of pars 
mediate: it becomes flat, finally ending on an 
aponeurosis. The aponeurosis extends distally 
between the bellies of pars lateralis and medialis, 
and fuses with them. 
Par^ medialis (Fig. 1: GAM) is the largest ol 
the three parts of M. gastrocnemius and arises by 
fleshy fibers from the patellar ligament, crista 
cnemialis cranialis, and the facies gastrocnemialis 
of the tibiotarsus. The large flat belly covers most 
of the medial surface of the lower leg and embeds 
a large sesamoid in its distal half. 
M. plantaris (Figs. 4, 5: PLA) arises fleshy 
from the proximal seventh of the caudomedial 
surface of the tibia. Its roughly triangular belly 
extends along the proximal third of the shank and 
gives rise to a slender ossified tendon, which 
inserts on the proximal end of the medial side of 
die tibial cartilage. 
M popliteus (Fig. 5: POP) is the deepest 
muscle on the caudal surface of the lower leg 
near the proximal end. It is small and roughly 
triangular in shape, arising directly from the 
caudomedial surface of the fibular head. The 
belly broadens mediodistally and inserts on 
tuberositas poplitea of the tibia. 
M. flexor perforans et perforatus digiti II 
'figs. I, 2: FPPD2) is composed of two parts. 
Hie dorsal head is large and originates fleshy 
from the patellar ligament and ansa m. iliotibu- 
Inns, The ventral head is partly fleshy from the M. 
ribulans longus and the crista cnemialis lateralis 
°f Ihe tibia. The belly of the dorsal head tapers 
J nd embeds a sesamoid at its distal third, before 
foxing with the belly of the ventral head about 
two-thirds of the way down (he shaft of the lower 
leg. The insertion tendon passes through the tibial 
cartilage and hypotarsus, and is ossified again for 
most of its length along the tarsometatarsus, and 
hnally attaches to the vcntroproximal surface ot 
foe second phalanx of digit II. 
M. flexor perforans et perforatus digiti 111 
(Figs. 1. 2: FPPD3) is a bipennate muscle that is 
visible superficially on the lateral surface of 
Proximal end of the lower leg. It arises by fleshy 
libers from the patellar ligament. The belly is 
strongly attached to M. flexor perforans et 
Perforatus digiti 11 and M. I'ibularis longus. ending 
near the middle of the tibiotarsus in a tendon 
which is ossified for most of the length before 
reaching the tibial cartilage. The tendon of M. 
flexor perforans el perforatus digiti III and M. 
flexor perforans digiti IV is enclosed in the 
sheath-like tendon of the M. flexor perforans 
digiti 111 when passing through the tihial cartilage 
and hypotarsus. The tendon is again ossified for a 
considerable distance along the caudal side of the 
tarsometatarsus before receiving a small branch 
from the tendon of M. flexor perforans digiti 111. 
Opposite phalanx I of digit III, it perforates the 
tendon of the M. flexor perforans digiti III. and is 
in turn perforated by M. flexor digitorum longus. 
The insertion is on the ventral surface near the 
middle part of the second phalanx. 
M. flexor perforans digiti IV (Figs. 2.4: FPD4) 
is visible in the caudolateral side of the lower leg 
after removing M. gastrocnemius, and has three 
heads of origin. The largo medial head originates 
by fleshy fibers from the intercondylar area of the 
femur. The intermediate middle head arises by 
aponeurosis from the lateral surface of the lateral 
condyle of the femur, and ansa m. iliofibularis. 
The smallest lateral head, in common with those 
of Mm. flexores perforate digitii II and HI, 
attaches to a heavy combined tendon, which 
arises from the fibular head and receives the 
tendon of insertion of M. ambient. The belly 
terminates about three-fourths the way down the 
lower leg. The tendon of insertion is ossified for a 
considerable distance from the distal part oi the 
belly to the distal end of the tibiotarsus. It is 
enclosed in the sheath-like tendon of the M. flexor 
perforans digiti Ill. in common w ith the tendon ol 
M. flexor perforans et perforatus digiti III when 
passing through the tibial cartilage and hypotar¬ 
sus, and is ossified again in the middle portion of 
the tarsometatarsus. 
M. flexor perforans digiti III (Fig. 4: FPD3) lies 
medially to M. flexor perforans digiti IV and 
arises by two heads. The larger medial head 
originates by aponeurosis from the intercondylar 
region of the femur, and the belly gives rise to a 
definite ossified tendon above the point ol union 
with the lateral head. The lateral head arises from 
the distal part of the combined tendon, deep to the 
lateral head of M. flexor perforans digiti IV. The 
slender, fusiform belly of the lateral head forms 
an unossified tendon before fusing with the 
ossified tendon of the medial head at the distal 
end of the tibiotarsus. The insertion tendon 
broadens at the caudal-most part or the tibial 
cartilage and encloses the tendon of M. flexor 
