444 MUSCLES. 



The CrurcBus, 



Is almost completely overlapped and concealed by the two 

 vasti, and is immediately behind the rectus femoris. The edge 

 of the vastus externus, above, is very distinguishable from it, as 

 it overlaps it, and is rounded off, besides being somewhat sepa- 

 rated by vessels. But the origin of the vastus internus is not 

 so distinguishable, as the fibres of the two muscles run into each 

 other; it is, therefore, necessary, most frequently, to cut through 

 some of their fibres on the internal face of the os femoris, on a 

 level with the trochanter minor. The cruraeus will be seen to 

 arise, fleshy, from all the fore part of the bone, and from all its 

 outside as far as the linea aspera. Between the internal edge 

 of this muscle and the linea aspera, the interior face of the os 

 femoris is free or unoccupied, the breadth of an inch along the 

 whole shaft of the bone, which is very readily seen by turning 

 off the vastus internus. 



The crurseus is inserted into the posterior face of the tendon 

 of the rectus below, and into the upper surface of the patella. 



It also extends the leg. 



The Ligamentum Patellae is the common chord by which the 

 action of the last four named muscles is communicated to the 

 tibia. It is a flattened thick tendon, an inch and a half wide, 

 arising from the inferior edge of the patella, and inserted into 

 the tubercle of the tibia. Between its insertion and the head 

 of the tibia, is a bursa. Besides this, a fascia or tendinous ex- 

 pansion, (Involucrum,) an appurtenance of the fascia femoris, as 

 mentioned before, comes from the inferior ends of these mus- 

 cles, extends itself over the whole of the anterior and lateral 

 parts of the knee joint, and is inserted into the head of the tibia 

 and of the fibula. Through this it happens that, even when 

 the patella or its tendon is fractured, some motion or extension 

 may be communicated to the leg from the thigh. 



In consequence of the common insertion of these four mus- 

 cles, some anatomists describe them as but one, under the name 

 of Quadriceps Femoris.* 



* Scemmering de Corp. Hum. Fab. 



