GLUT^EAL REGION 231 



raised from the bed in which it lies. Its deep surface will 

 be seen to consist of four or five rounded slips separated by 

 deep grooves or furrows. The surface of the small sciatic 

 notch on which this tendon glides is coated with smooth 

 cartilage, which is raised into ridges corresponding to the 

 grooves on the surface of the tendon. A large bursa mucosa 

 is interposed, which still further facilitates the play of the 

 tendon round the notch. 



The ;;/. quadratus femoris lies between the gemellus inferior 

 and the adductor magnus. It is a flat oblong muscle which 

 arises from the lateral border of the tuber ischiadicum, and 

 proceeds horizontally to gain insertion into the quadrate 

 tubercle, and into a line which extends distally from it, on 

 the back of the femur, for two inches (Fig. 78, p. 209). 



Dissection. The nerve to the quadratus femoris should now be traced 

 to its termination. This can be done by reflecting the two gemelli muscles 

 anterior to which it runs. When followed as far as the inferior gemellus, care 

 should be taken to secure the little twig it gives to that muscle. Lastly, 

 reflect the quadratus femoris by detaching it from the femur and throwing 

 it towards the ischial tuberosity. By this dissection not only is the whole 

 length of the nerve to the quadratus femoris exposed, but also a consider- 

 able portion of the posterior aspect of the capsule of the hip-joint is laid 

 bare ; further, the obturator externus muscle, the termination of the medial 

 circumflex artery, and the insertion of the ilio-psoas are brought into 

 view. The posterior part of the capsule of the hip-joint which is exposed 

 consists largely of circularly arranged fibres. 



Nerve to the Quadratus Femoris. This small nerve 

 runs distally on the hip bone and passes successively 

 anterior to the following structures : the sciatic nerve, the 

 gemellus superior, the tendon of the obturator internus, the 

 gemellus inferior. It gives the nerve of supply to the gemellus 

 inferior and a twig to the hip-joint, and ends by sinking into 

 the deep surface of the quadratus femoris. 



M. Obturator Externus. This muscle can now be seen 

 winding round the neck of the femur and finally ending in a 

 rounded tendon which is implanted into the fossa trochan- 

 terica of the femur (Fig. 78, p. 209). Its origin has already 

 been examined. 



Arteria Circumflexa Femoris Medialis (O.T. Internal Cir- 

 cumflex Artery). This vessel comes to an end at the proximal 

 border of the adductor magnus by dividing into its ascending 

 and transverse terminal branches. The ascending branch runs 

 obliquely proximally and laterally, anterior to the quadratus 

 femoris and upon the posterior surface of the obturator ex- 



