1. =Sartorius= (Figs. 180, 202, 203).—This long and rather narrow muscle
is the most anterior one of the first layer. It extends from the
sublumbar region to the lower and inner part of the stifle.
_Origin._—The iliac fascia and the tendon of the psoas minor.
_Insertion._—The internal straight ligament of the patella and the
adjacent part of the tuberosity of the tibia.
_Action._—To flex the hip joint and adduct the limb.
_Structure._—The muscle is very thin at its origin, but becomes thicker
and narrower as it passes downward and a little backward. It terminates
near the stifle joint on an aponeurosis which blends with that of the
gracilis and with the fascia of the leg.
_Relations._—Superficially, the inguinal (Poupart’s) ligament, the
abdominal muscles, the skin and fascia, and the saphenous vessels and
nerve; deeply, the ilio-psoas, quadriceps femoris, and adductor. It
forms the anterior boundary of the femoral canal, in which the femoral
artery and vein and the deep inguinal lymph glands are situated (Fig.
451).
_Blood-supply._—Femoral artery.
_Nerve-supply._—Femoral and saphenous nerves.
2. =Gracilis= (Figs. 186, 199, 202, 203).—This is a wide, flat,
quadrilateral muscle, situated behind the sartorius, which it exceeds
greatly in extent.
_Origin._—The middle third of the pelvic symphysis, the prepubic tendon
and pubo-femoral ligament, and the ventral surface of the pubis behind
the prepubic tendon.
_Insertion._—The internal straight ligament of the patella, the internal
surface of the tibia in front of the lateral ligament of the stifle
joint, and the fascia of the leg.
_Action._—To adduct the limb. It may also rotate it inward.
_Structure._—The muscle arises by a strong tendon, chiefly in common
with the opposite muscle. Its direct attachment to the ventral surface
of the pelvis is not so extensive as a superficial inspection would
suggest. The origin of the muscle presents anteriorly a round
perforation for the passage of the external pudic vein. The belly is
composed of parallel bundles, and is marked by a superficial furrow
which, however, does not indicate a muscular division. It terminates on
the inner surface of the stifle on a thin wide tendon which blends in
front with that of the sartorius, below with the crural fascia.
_Relations._—Superficially, the skin and fascia, the penis or mammary
gland, and the saphenous vessels and nerve; deeply, the pectineus,
adductor, semimembranosus and semitendinosus, and, at the middle of the
femur, the femoral vessels; anteriorly, the sartorius. In the upper
third of the thigh the sartorius and gracilis are separated by a
triangular interval (femoral triangle), in which lie the deep inguinal
lymph glands and the femoral vessels.
_Blood-supply._—Femoral and deep femoral arteries.
_Nerve-supply._—Obturator and saphenous nerves.