The Muscles — 127 
The caput femorale (externum) originates by a 
strong, short tendon from the lateral and posterior 
surface of the external condyle of the femur. This 
head has a double insertion: (1) from the outer, 
fibular border of the muscle separates off a tendon 
that spreads out in the first layer of the plantar 
tendon-muscle; (2) the chief part of caput I. 
becomes a broad, flat, subcutaneous tendon which 
is covered by the tendon Achilles and serves as the 
origin of the short flexors of the toes. 
II. The caput tibiale (internum) springs with- 
out a tendon from the posterior surface of the 
head and the proximal third of the tibia. The 
broad and somewhat flat muscle has two insertions: 
(1) on the plantar and medial border of the first 
basis metatarsi; (2) the chief insertion on the outer 
border of the rudimentary fifth toe, after forming, 
with the tendon of the flexor tibialis externus, the 
tendon Achilles. 
Flexor Longus Digitorum (Plate IV., Fig. 4) 
(Langer durchbohrender gemeinschaftlicher Zehen- 
beuger). A many-headed muscle visible on the 
posterior side of the lower leg after removal of the 
preceding muscle. (a) Caput externum:a flat, fairly 
broad muscle which springs from the outer and 
posterior surface of the fibula. Arriving at the 
astragalo-scaphoid bone, it forms a very strong ten- 
don which unites with the still stronger tendon of the 
other head and both together form the broad initial 
tendon of the flexor digitorum communis brevis 
