226 MYOLOGY, OR ANATOMY OF MUSCULAR SYSTEM 



M. subcrureus (articularis genu, p. n.} is the name of a few 

 fibers which may be regarded as the deepest layer of the crureus. 

 Origin, anterior surface of the femur in the lower fourth; 

 insertion, separated by a fat layer from the vasti into the 

 synovial membrane of the knee-joint. 



These muscles may be bilaminar. 



Hunter's canal is a three-cornered passage in the middle 

 two-fourths of the thigh, in the angle between the adductors 

 magnus and longus and vastus internus. It is made a canal 

 by a bridge of fascia, and contains the femoral artery, vein, 

 and internal saphenous nerve. 



Nerves. Anterior crural for the quadriceps and sartorius; 

 superior gluteal for the tensor vaginae femoris. 



Actions. Sartorius flexes the hip and knee with Aversion 

 of the thigh; rotates the leg inward. 



Quadriceps femoris extends the leg; not necessary for the 

 maintenance of the erect attitude. 



Rcctus femoris also flexes the hip; its posterior head is tense 

 when the thigh is bent. Lower fibers of the vastus internus 

 draw the patella in. 



Tensor vagina femoris rotates in and abducts, assisted by 

 the gluteus maximus; counteracts the gluteus maximus, which 

 tends to draw the iliotibial band backward. 



The Posterior Femoral Region (Hamstrings) 



1. M. Biceps Femoris. Origin, long head by a tendon 

 common to it and semitendinosus from inner impression on 

 the lower part of the ischial tuberosity, and from the sacro- 

 sciatic ligament; short head from the middle third of the outer 

 lip of the linea aspera and external intermuscular septum; 

 fibers from both heads end in a tendon inserted into the upper 

 and outer part of the head of the fibula by two portions em- 

 bracing the external lateral ligament; some fibers pass forward 

 and inward to the external tuberosity of the tibia and to the 

 fascia of the leg. 



2. M. Semitendinosus. Rises from the tuberosity of the 

 ischium and tendon common to it and biceps for 3 inches. 

 Terminates in the lower third of the thigh in a long, slender 

 tendon, and curves forward in an expanded form to insert 

 on the upper part of the inner surface of the tibia or anterior 



