POSTERIOR FEMORAL REGION. 233 



from the margin of the bone which surrounds the obturator 

 foramen, and from the membrane which stretches across it; 

 it passes over the lesser sacro-ischiatic notch, which acts as 

 a pulley on which its tendon plays in the change of direction 

 which it assumes to reach its insertion. The belly of the 

 muscle is broad and flat, and, tapering to a rounded tendon, 

 embraced by the gemelli muscles, is inserted into the digital 

 >ssa of the great trochanter. On dividing this muscle, it 

 ll be seen that the ischiatic notch is covered with cartilage 

 id provided with a synovial bursa. 



The GEMELLUS SUPERIOR arises from the spine of the 

 3hium ; the GEMELLUS INFERIOR from the upper and pos- 

 irior part of the tuberosity of the ischium. The superior is 

 isually the smaller of the two, and they embrace, and either 

 'holly or partially conceal, the tendon of the obturator 

 luscle, into which some of their fibres are inserted, while 

 rest are inserted with that tendon into the digital fossa 

 the greater trochanter. These two muscles thus con- 

 fute appendages of the obturator interims, and form, as 

 were, a "marsupium," or pouch, to that muscle, which, 

 >m having connected with it a well-marked bursa, was 

 )metimes called, by the old anatomists, the "bursalis," or 

 marsupialis" muscle. The gemellus superior is sometimes 

 >sent. 



The QUADRATUS FEMORIS MUSCLE lies next below the 

 gemellus inferior; it is a flat and quadrangular muscle, 

 arising from the external border of the tuberosity of the 

 ischium, and inserted into the linea quadrati at the pos- 

 terior and lower part of the greater trochanter. This 

 muscle is tendinous at its insertion, and its lower border 

 is in relation with the adductor magnus ; it is crossed by 

 the great sciatic nerve, and the internal circumflex artery 

 emerges at its upper border. Just above this muscle will 

 be seen the tendon and part of the belly of the obturator 

 externus muscle, going to be inserted into the digital fossa. 



DISSECTION X. 



POSTERIOR FEMORAL REGION. 



An incision is to be carried down the back of tbe tbigb, a short 

 distance below the fold of the knee-joint, and the integument reflected. 



20* 



