VASTUS INTERNUS MUSCLES. 239 



to the base of the great trochanter in front, and to a ridge on its outer 

 side ; to the line extending from the great trochanter to the hnea 

 aspera and to the outer border of the linea aspera itself in its upper half ; 

 the aponeurosis being prolonged on the outer surface of the muscle, also 

 gives origin to numerous muscular fibres. The muscle forms a somewhat 

 rhomboidal mass of considerable thickness, and descends obliquely in- 

 wards and forwards on the outer surface of the vastus internus to be 

 inserted by a broad flat tendon into the tendon of the rectus muscle 

 and the patella. 



lielatiom. — This muscle forms the large mass on the outer and upper part of 

 the thigh. Its deep surface rests on the vastus internus : its outer surface is 

 covered by the fascia lata and by the aponeurotic insertions of the gluteus 

 maximus and tensor vagina3 femoris. Anteriorly it is in contact with the rectus 

 femoris and external circumflex arteries, 



c and d. The muscles usually described as vastus internus and 

 crureus are inseparably united and form the inner or deep head of the 

 common extensor. The fibres of this head may, however, be easily 

 separated into a superficial and a deep set. The superficial fibres form 

 a continuous lamina or mantle (Henle) arching over the front and both 

 sides of the shaft of the femur, and completely enclosing the deeper 

 fibres which are only seen on cutting through the mantle. These 

 fibres of the mantle descend in ditterent directions, the middle or 

 anterior fibres, while arching forwards being nearly parallel to the 

 femur, and the lateral fibres being more oblique ; this obliquity increases 

 towards the lower part of the muscle, -where the fibres are nearly 

 horizontal. The anterior fibres arise from the middle of the 

 anterior intertrochanteric line ; the inner lateral fibres arise from 

 the line running from the anterior intertrochanteric line in front 

 of the small trochanter to join the inner line leading to the linea 

 aspera, from the lower half of that inner line, from the inner lip 

 of the linea aspera, and from the internal intermuscular septum. 

 The line of origin of the outer lateral fibres runs from the ante- 

 rior intertrochanteric line obliquely across the front of, and down 

 the outer surface of the shaft of the femur, immediately in front 

 of, and closely connected with the origin of the vastus externus. 

 The lower lateral fibres on the outside of the limb reach consider- 

 ably beyond the lower border of the vastus externus, taking origin ft-om 

 the outer lip of the linea aspera and from the external Intermuscular 

 septum. From this extensive origin the .fibres converge to the under 

 surface and margins of a flat tendon which runs upwards for the most 

 part on the; surface of the anterior fibres. This tendon becomes in- 

 corporated inferiorly with the tendons of the rectus femoris and vastus 

 externus, and so becomes attached to the upper and lateral margins of 

 the patella. Many of the lowest lateral fibres on both sides are also 

 attached directly to the sides of the patella and to the fascia lata at the 

 sides of the knee-joint. 



The deep set of fibres, for which the name of crureus may be still 

 retained, arises from the anterior aspect only of the shaft of the femur 

 for about its middle two-thirds, the upper part of the origin being 

 separated by a slight interval from the origin of the superficial fibres, 

 and the lower part reaching to within three inches of the patellar 

 surface. These fibres pass obliquely downwards and forwards to be 



