572 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 
inserted on the outer side of the proximal end of the distal phalanx of the second or 
inner digit. The second or outermost slip of the extensor brevis of the foot (£.0.d’) has 
a double head of origin; the longer one arises from the outer surface of the astragalus, 
and afterwards joins the second head of origin, which comes from the cuboid. The two 
heads form one belly, which gives off a single tendon, ultimately inserted into the 
outer side of the third digit. 
The peroneus longus (P.l, fig. 15) is of good size. It arises by a short, broad tendon 
from the external condyle of the femur, and then forms a considerable belly, which 
reaches downwards for about two thirds of the length of the limb. Its inferior long 
and strong tendon passes behind the outer malleolus in a separate groove, and beneath 
the posterior and outer border of the biceps, and, as it goes behind the outer prominence 
of the cuboid, proceeds to the plantar surface, to the head of the metatarsal of the 
hallux, but joins by fascia to that of the fourth. 
The peroneus brevis (P.b) and the peroneal muscle next to be described arise together, 
the whole length of the fibula, upon the outer and posterior surface; the tendon of the 
former is inserted into the proximal end of the fifth metacarpal bone. 
Peroneus quinti digiti—As already mentioned, this muscle arises in very close union 
with the peronzus brevis; but it lies above and higher than it, having an origin from the 
upper third of the fibula. The tendon of the peronzus quinti digiti lies the more super- 
ficial of the two, and on the outer side of the dorsum of the foot. It continues strong 
to its insertion (P.5.d), which is on the outer side of the proximal end of the proximal 
phalanx of the outer or fifth digit, where it finally becomes very wide. 
Both the peroneus tertii and the peroneus quarti digiti ave absent. 
Pectineus.—A short, moderate-sized muscle, nearly transverse to the long axis of the 
body (Pe, figs. 33, 36), and cutting the angle formed by the femur and lower leg. It 
arises by a broad, short, strong tendon from the brim of the pelvis, immediately behind 
the prominence where the psoas is inserted, and, passing outwards and forwards, is fixed 
into the upper part of the tuberosity of the internal condyle of the femur. 
Use. This muscle, with others, restrains the movements of the leg by its remarkably 
low attachment to the femur. It acts also as an inward flexor—for instance, when the 
knees approach. 
The rectus femoris (Rf) is shorter and only a little thicker than the combined tensor 
vaginee femoris and sartorius; it is in great part covered by the latter muscle. It 
possesses only one head of origin; this is fleshy, and arises from the lower half of the 
hollow between the acetabulum and the spinous process of the ilium. The muscular 
belly broadens considerably, and is inserted into the upper part of the patella. It isa 
flexor of the thigh. 
The vastus internus (V.i)is small. It arises the whole length of the inner side of the 
shaft of the short femur, and is inserted into the inner side of the patella and partly 
into the capsule of the knee-joint. 
