422 THE MUSCLES AND FASCIAE. 



terior surface, and, gradually becoming narrowed into a flattened tendon, is 

 inserted into the patella in common with the Vasti arid Crureus. 



Relations. By its superficial surface, with the anterior fibres of the Gluteus 

 minimus, the Tensor fasciae femoris, the Sartorius, and the Iliacus ; by its lower 

 three-fourths, with the fascia lata. By its posterior surface, with the hip-joint, 

 the external circumflex vessels, branches of the anterior crural nerve, and the 

 Crureus and Vasti muscles. 



The Vastus externus is the largest part of the Quadriceps extensor. It arises 

 by a broad aponeurosis, which is attached to the upper half of the anterior iriter- 

 trochanteric line, to the anterior and inferior borders of the root of the great 

 trochanter, to the outer lip of the gluteal ridge, and to the upper half of the outer 

 lip of the linea aspera : this aponeurosis covers the upper three-fourths of the 

 muscle, and from its inner surface many fibres take origin. A few additional 

 fibres arise from the tendon of the Gluteus maximus, and from the external inter- 

 muscular septum between the Vastus externus and short head of the Biceps. The 

 fibres form a large fleshy mass, which is attached to a strong aponeurosis, placed 

 on the under surface of the muscle at its lower part : this becomes contracted and 

 thickened into a flat tendon, which is inserted into the outer border of the patella, 

 blending with the great Extensor tendon, and giving an expansion to the capsule 

 of the knee-joint. 



Relations. By its superficial surface, with the Rectus, the Tensor fasciae 

 femoris, the fascia lata, and the tendon of the Gluteus maximus, from which it is 

 separated by a synovial bursa. By its deep surface, with the Crureus, some large 

 branches of the external circumflex artery and anterior crural nerve being inter- 

 posed. 



The Vastus internus and Crureus appear to be inseparably united, but when 

 the Rectus femoris has been reflected, a narrow interval Avill be observed extending 

 upward from the inner border of the patella between the two muscles. Here they 

 can be separated, and the separation should be continued upward as far as the 

 lower part of the anterior intertrochanteric line, where, however, the two muscles 

 are frequently continuous. 



The Vastus internus arises from the lower half of the anterior intertrochanteric 

 line, the spiral line, the inner lip of the linea aspera, the upper part of the internal 

 supra-condylar line, and the tendon of the Adductor magnus and internal inter- 

 muscular septum. Its fibres are directed downward and forward, and are chiefly 

 attached to an aponeurosis which lies on the deep surface of the muscle and is 

 inserted into the inner border of the patella and the Quadriceps extensor tendon, 

 an expansion being sent to the capsule of the knee-joint. 



The Crureus arises from the front and outer aspect of the shaft of the femur in 

 its upper two-thirds and from the lower part of the external intermuscular septum. 

 Its fibres end in a superficial aponeurosis, which forms the deep part of the Quad- 

 riceps extensor tendon. 



Relations. The inner edge of the Crureus is in contact with the anterior edge 

 of the Vastus internus, but when separated from each other, as directed above, the 

 latter muscle is seen merely to overlap the inner aspect of the femoral shaft without 

 taking any fibres of origin from it. The Vastus internus is partly covered by the 

 Rectus and Sartorius, but where these separate near the knee it becomes superficial, 

 and produces a well-marked prominence above the inner aspect of the knee. In 

 the middle third of the thigh it forms the outer wall of Hunter's canal, which 

 contains the femoral vessels and the long saphenous nerve the roof of the canal 

 being formed by a strong fascia which extends from the Vastus internus to the Ad- 

 ductores longus and magnus. The Crureus is almost completely hidden by the 

 Rectus femoris and Vastus externus. The deep surface of the two muscles is in 

 relation to the femur and Subcrureus muscle. A synovial bursa is situated between 

 the femur and the portion of the Quadriceps extensor tendon above the patella ; in 

 the adult it communicates Avith the synovial cavity of the knee-joint. 



The tendons of the different portions of the Quadriceps extensor unite at the 



