POSTERIOR FEMORAL REGION. 



233 



91.* 



The Biceps Jlexor cruris (bis, double, xstpaXvi, head) arises by two 

 heads, one by a common tendon with the semi-tendinosus ; the other 

 muscular, and much shorter, from the lower two-thirds of the 

 external border of the linea aspera. This muscle forms the outer 

 hamstring, and is inserted by a strong tendon into the head of the 

 fibula. 



Relations. By its superficial or posterior surface with the gluteus 

 maximus and fascia lata. By its deep or an- 

 terior surface with the semi-membranosus, ad- 

 ductor magnus, vastus externus, the great 

 sciatic nerve, popliteal artery and vein, and 

 near its insertion with the external head of the 

 gastrocnemius, and plantaris. By its inner 

 border with the semi-tendinosus, and in the 

 popliteal space with the popliteal artery and 

 vein. 



The Semi-tendinosus, remarkable for its 

 long tendon, arises in common with the long 

 head of the biceps, from the tuberosity of the 

 ischium. It is inserted into the inner tubero- 

 sity of the tibia. 



Relations. By its superficial surface with 

 the gluteus maximus, fascia lata, and at its 

 insertion with the synovial bursa which sepa- 

 rates its tendon from the expansion of the 

 sartorius. By its deep surface with the semi r 

 membranosus, adductor magnus, internal head 

 of the gastrocnemius, and internal lateral liga- 

 ment of the knee-joint, the synovial bursa com- 

 mon to it, and the tendon of the gracilis being 

 interposed. By its inner border with the gra- 

 cilis ; and by its outer border with the biceps. 



These two muscles must be dissected from 

 the tuberosity of the ischium, to bring into 

 view the origin of the next. 



The Semi-membranosus, remarkable for the 

 tendinous expansion upon its anterior and 

 posterior surface, arises from the tuberosity of the ischium, in 

 front of the common origin of the two preceding muscles. It is 

 inserted into the posterior part of the inner tuberosity of the tibia ; 

 at its insertion the tendon splits into three portions, one of which 

 is inserted in a groove on the inner side of the head of the tibia, 



* The muscles of the posterior femoral and gluteal region. 1. The gluteus medius. 

 2. The gluteus maximus. 3. The vastus externus covered in by fascia lata. 4. The 

 head of the biceps. 5. Its short head. 6. The scmi-tendinosus. 7. The semi-mem- 

 branosus. 8. The gracilis. 9. A part of the inner border of the adductor magnus. 

 10. The edge of ths sartorius. 11. The popliteal space. 12. The gastrocnemius mus- 

 cle ; its two heads. The tendon of the biceps forms the outer hamstring ; and the sar- 

 torius with the tendons of the gracilis, scmi-tendinosus, and semi-membranosus, the 

 inner hamstring. 



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