340 THE MUSCULAR SYSTEM. 
named the crural canal. The wall of this is known as the crural sheath. This 
canal is the passage through which a femoral hernia enters the thigh. Its upper 
limit is the crural ring, placed behind Poupart’s hgament in front. of the origin of 
the pectineus muscle from the pubis; external to Gimbernat’s ligament, and 
internal to the femoral vein. In front of it the fascia transversalis forming the 
sheath is thickened to form the deep crural arch. The part of Poupart’s ligament 
in front of the ring is called the superficial crural arch. The deep epigastric artery 
separates the crural ring from the internal abdominal ring. The crural canal 
ordinarily contains fat which is continuous above with the extra-peritoneal tissue. 
The crural ring is filled by a plug of fat or a lymphatic gland, constituting the 
crural septum. 
The crural canal ends behind the saphenous opening, covered by the cribriform 
fascia; the falciform ligament crosses over it and conceals its upper portion. The 
course of a femoral hernia is determined by this band of fascia lata. The hernia 
descends through the crural ring, pushing the crural septum before it; it traverses 
the crural canal, and is directed forwards through the saphenous’ opening. The 
anterior part of the hernia, being pressed upon and retarded by the crural arches 
and by the falciform ligament, the posterior part pushes onwards, hooks round the 
falciform ligament, and is directed upwards over Poupart’s ligament. The cover- 
ings of a femoral hernia, in addition to peritoneum and extra-peritoneal tissue 
(crural septum), are crural sheath, cribriform fascia, superficial fascia, and skin. 
THE MUSCLES ON THE FRONT OF THE THIGH. 
The muscles on the front of the thigh include the sartorius, quadriceps extensor, 
ilio-psoas, and pectineus muscles. 
The sartorius, a long strap-like muscle stretching obliquely across the thigh, 
arises from the anterior superior spine of the ilium and half of the notch 
below it. It passes down the thigh to the inner side of the knee, where it is 
inserted by aponeurotic fibres into the inner surface of the shaft of the tibia just 
below the inner tuberosity, and by its borders into fascial expansions which join 
the capsule of the knee-joint and the fascia lata of the leg. 
The sartorius is superficial in its whole extent. It is so twisted on itself that 
in the upper third of its length its superficial surface looks forwards, in the lower 
third inwards at the side of the knee. It passes diagonally down the thigh, separ- 
ating the quadriceps extensor externally from the adductor muscles internally. Its 
upper third forms the outer boundary of Scarpa’s triangle; its middle third forms 
the roof of Hunter’s canal; and its lower third, in contact with the inner side of the 
knee, is separated from the tendon of the gracilis muscle by the long saphenous 
nerve and a branch of the anastomotic artery. A bursa lies beneath the tendon at 
its insertion. The sartorius conceals in its upper third the external circumflex 
artery and branches of the anterior canal nerve, and it covers the femoral vessels 
in Hunter’s canal. 
The quadriceps extensor (im. quadriceps femoris) lies between the sartorius 
on the one hand and the tensor fasciz femoris and ilio-tibial band on the other; 
it is composed of four muscles—the rectus femoris, vastus externus, crureus, and 
vastus internus. 
The rectus femoris has a double tendinous origin. (1) The straight head 
arises from the anterior inferior spine of the ilium; (2) the reflected head springs 
from a rough groove on the dorsum ilii just above the highest part of the 
acetabulum. A bursa lies beneath this head of origin. The two heads, bound 
together and connected to the capsule of the hip-joint by a band of fascia derived — 
from the under surface of the tensor fascie femoris (ilio-tibial band), give rise to a 
single tendon which extends for some distance on the front of the muscle, and from 
which the muscular fibres arise. The muscular fibres springing from this tendon, — 
and also from a median septal tendon, present a bipennate arrangement, and end — 
below in a broad tendon which passes upwards for some distance along the posterior 
surface of the muscle. This tendon gradually narrows towards the knee, and — 
spreading out again, is inserted into the upper border of the patella. It receives — 
