342 THE MUSCULAR SYSTEM. ~ 
the synovial membrane of the knee-joint, lies beneath its tendon in front of the 
lower end of the shaft of the femur. 
The vastus externus (m. vastus lateralis) has an origin, partly fleshy, partly 
membranous, (1) from the shaft of the femur, from the anterior tubercle, along 
the lower border of the great trochanter, the gluteal ridge, and the upper half 
of the linea aspera; and (2) from the fascia lata and external intermuscular 
septum. 
It forms a thick broad muscle directed downwards and forwards, and is 
inserted into (1) the outer border of the tendon of the rectus femoris, (2) the upper 
and outer border of the patella, and (3) the capsule of the knee-joint, and the 
VASTUS INTERNUS 
RECTUS FEMORIS 
Internal saphenous nerve. s fx Y 
as 1 7. : ; ¢ VASTUS EXTERNUS 
Femoral vessels & A 
Vie, — CRUREUS 
Femur 
ADDUCTOR aces i 
GRACILISm 
Biceps (short head) 
XS 
SEMIMEMBRANOSUS~ SS 
vA 
SEMITENDINOSUS/ / 
Great sciatic nerve 
Fic. 252.—TRANSVERSE SECTION OF THE THIGH (HUNTER’S CANAL). 
external lateral ligament of the patella. The vastus externus is covered super- 
ficially by the fascia lata and the ilio-tibial band. A bursa intervenes between 
it and the membranous insertion of the gluteus maximus: at its inner border is 
the rectus femoris; and along its outer border, but on a deeper level, is the 
crureus, which is also to a large extent concealed by the muscle. Between the 
vastus externus and crureus is the descending branch of the external circumflex 
artery. 
The vastus internus (im. vastus medialis) is larger than the vastus externus 
and has a more extensive origin, from (1) the shaft of the femur, from the anterior 
tubercle, spiral line, linea aspera, and the upper two-thirds of the line leading from 
the linea aspera to the internal condyle of the femur; (2) the membranous 
expansion of the fascia lata which lies beneath the sartorius and forms the roof 
of Hunter's canal; and (3) the internal intermuscular septum and tendon of the 
adductor magnus. 
From its origin the muscle is directed downwards and outwards towards the 
knee; it is inserted into (1) the inner border of the rectus tendon, (2) the upper 
and inner border of the patella, and (3) the capsule of the knee-joint and the 
internal lateral hgament of the patella. The vastus internus is superficial except 
at its origin, which is concealed by the sartorius and femoral vessels. Along its 
outer side are the rectus and crureus; the muscle conceals the inner side of the 
shaft of the femur and the crureus, with which it is closely incorporated in its 
lower two-thirds. 
The crureus muscle (m. vastus intermedius) arises (1) from the upper two-thirds 
of the shaft of the femur on the anterior and external surfaces, (2) from the lower 
