38 
through which the tendon of the biceps glides; a strong ligament 
from the outer ridge of the fibula passes backwards to be attached 
to the confluence of the two tendons. The carneous fibres of the 
external gastrocnemius come off from the outer side of the inferior of 
these tendons, and from the fascia covering the outer surface of the 
muscles of the leg: they are continued in a somewhat penniform 
arrangement two-thirds down the leg, upon the inner surface of the 
muscle, where they end inastrong subcompressed tendon. ‘This joins 
its fellow tendon, from the internal gastrocnemius, behind the ankle- 
joint, and both expand into a thick, strong, ligamentous aponeurosis, 
which extends over three-fourths of the posterior part of the tarso- 
metatarsal joint. The lateral margins of this fascia are bent down 
under the flexor tendons behind the joint, and become continuous 
with a strong ligamentous layer gliding upon the posterior surface 
of the distal condyles of the tibia, and attached to the tendons of the 
peroneus and tibialis anticus; the conjunction of the thickened ten- 
dons of the gastrocnemii with this deeper-seated layer of ligamento- 
tendinous substance constitutes a trochlear sheath lined by synovial 
membrane, through which the flexor tendons of the toes glide. The 
synovial membrane of the ankle-joint is continued upwards half 
an inch above the articular surface of the bone, between it and the 
cartilaginous pulley. Below the joint the margins are inserted into 
the lateral ridges of the tarso-metatarsal bone, becoming gradually 
thinner as they descend, and ending below in a thin semilunar edge 
directed downwards. 
The gastrocnemius internus has two powerful heads, one from the 
femur, the other from the tibia; the first arises fleshy from the in- 
ternal condyle of the femur, expands as it descends, and receives 
additional fibres from the lower edge of the accessorius semitendi- 
nosi. About one-fifth down the tibia, this muscular origin, in the 
right leg, terminated in a short flattened tendon, which became at- 
tached to the imner side of the tibial portion of the gastrocnemius 
internus. In the left leg the tendon soon divided; one portion 
passed to the soleus, the other went to join the tibial portion of the 
gastrocnemius internus. The second head, which is separated from the 
preceding by the insertion of the semitendinosus, arises partly from 
the internal and anterior part of the strong fascia of the knee-joint by 
short tendinous fibres, which almost immediately become fleshy, and 
partly from a well-defined triangular surface on the inner and ante- 
rior aspect of the head of the tibia: the fleshy fibres converge, 
receive the tendinous slip from the femoral portion, and end on the 
inner side of the muscle in a strong flattened tendon, about two- 
thirds down the leg: this joins the tendon of the gastrocnemius ex- 
ternus, and is inserted as described above. 
Soleus.—A slender flattened muscle arising from the inner and 
posterior side of the tibia, the tendon of which joins that of the gas- 
trocnemius internus, behind the tarsal joint. 
The flexor perforatus of the inner toe lies immediately anterior 
to the external gastrocnemius ; it arises fleshy from the outer condyle 
of the femur, below the tendinous origin of that muscle, and terminates 
