576 A MANUAL OF ANATOMY. 



the inner up of the linea aspera, from the internal intermus- 

 cular septum and the tendon of the adductor magnus (vas- 

 tus portion). 



Insertion. Into the upper border of the patella behind 

 the rectus femoris tendon (the crureus portion), into the 

 inner margin of the patella, and by an aponeurotic expan- 

 sion into the internal tuberosity of the tibia and the deep 

 fascia of the leg (vastus portion). 



Nerve Supply. The anterior crural. 



Action. To extend the leg ; the vastus internus through 

 its lower fibres resists the outward pull of the vastus ex- 

 tern us. 



The Ligamentum Patellae. 



This is the continuation of the tendons of the four 

 muscles described as attached to the patella, namely the 

 rectus femoris, the vastus externus, the vastus internus and 

 crureus, which having, in common, the action of extension 

 of the leg are known as the quadriceps extensor femoris. 

 The ligamentum patellae extends from the apex and lower 

 margins of the patella to the lower portion of the tibial 

 tubercle. It is about an inch wide above, and three-fourths 

 of an inch below, one-fourth of an inch thick, and from two 

 to three inches in length. 



The patella should be regarded as a sesamoid bone 

 developed within the tendon of the quadriceps extensor ; its 

 presence renders the action of those muscles much more 

 effective than they would be without it. 



Adductor Brevis. Figs. 1 1 9, 1 20. 



Origin. From the front of the body and descending 

 ramus of the pubes below the adductor longus and between 

 the gracilis and the obturator externus. 



