16 A Review of the Muscles used 
flexor perforatus digitorum, or, at least, with one of its 
divisions. 
The ambiens is overlaid by the sartorius muscle, and in 
the figure is brought into view only through the aid of 
a small dissecting-hook and chain, which pull it forwards 
in order that it may be better seen. / 
7. The femoro-caudal (Fig. 9) arises, tendinous, from the 
lower posterior border of the pygostyle. It soon becomes 
fleshy and as a narrow, muscular ribbon passes through 
the tissues overlying the lateral group of caudal muscles 
proper. Opposite the posterior border of the pelvis it 
expands to form a prettily shaped and compressed 
spindle, closely covering the obturator externus muscle and 
the side of that bone. As it nears the femur it again con- 
tracts, receives the fibres of its accessory head, and is fin- 
ally inserted upon the femoral shaft, at the posterior as- 
pect of its proximinal third. 
8. The accessory femoro-caudal arises beneath the over- 
arching part of the postacetabular portion of the ilium, just 
behind the acetabulum and beyond. Its fibres pass ob- 
liquely downwards and forwards to join with those of the 
femoro-caudal, and to become inserted with them into the 
upper part of the femur as already described. 
9. The semztendinosus (Figs. 8 and 9) is a marvelously 
well-developed muscle in this form, as is also its accessory 
head. Its origin fills about three-fourths of the nether cav- 
ity formed by the posterior over-arching portion of the ili- 
um, under which it arises. 
Posteriorly, the fibres forming its free margin are so ar- 
ranged as to create a rounded border ; the lower end of its 
arc terminating about opposite the post-pubis of the pelvis. 
From this origin’ the fibres of the semitendinosus pass 
downwards and forwards as a great, though somewhat 
compressed muscle. When within rather more than a 
centimetre’s length of the shaft of the femur, they termin- 
ate in an oblique tendinous raphe, which latter forms the 
bounding-line between this muscle and the next. 
10, The accessory semitendinosus (Figs. 8 and 9), is com- 
posed of coarser fibres than the muscle just described. It 
