Anatomy of Skeleton 



term is applied to the whole mass of bone that stands up at the base of the neck, and 

 does not quite correspond with the epiphysis. The epiphysial line is as shown in Fig. 118, 

 and the epiphysis includes the femoral tubercle at the top of the anterior intertrochan- 

 teric line and a part of what is descriptively the upper aspect of the neck. 



The front surface has (Fig. 118) a smooth area for a bursa under the tendon of 

 Gluteus minimus, which is inserted into the strong ridge along its outer border. The. 

 Ilio-trochanteric aponeurosis (p. 124) reaches the ridge below and internal to the 

 bursa. Pyriformis is inserted along the whole length of the upper crest of the tro- 

 chanter. The strong, direct tendon of the muscle runs mainly into the back half of the 



crest, where there is usually a facetted appearance 

 made by it and extending back to the unciform 

 end that overhangs the digital fossa. 



But this is not the whole attachment of the muscle. 

 If the structures are looked at in an ordinary dissection 

 the tendon of Pyriformis is seen (Fig. 117) to lie in plane 

 superficial to that of the Obturator internus and Gemelli, 

 but if the structures are divided and turned up the 

 Obturator tendon is still seen to be covered by the Pyri- 

 formis ; in other words, the Pyriformis partly surrounds 

 the Obturator insertion by means of an expansion passing 

 in front of it, and from this expansion, as shown in the 

 drawing, another aponeurotic sheet is continued to the top 

 of the Gluteus minimus tendon. The complete area of 

 Pyriformis attachment to the bone therefore is as seen in 

 the figure, and the sheet that passes in front of the 

 Obturator tendon is also continued into the fibres of the 

 upper retinaculum. 



Obturator internus and Gemelli are inserted 

 internal to and in front of the main tendon of 

 Pyriformis, on the inner side of the trochanter : 

 Gemellus inferior takes the lower and back part of 

 this insertion, and Gemellus superior is largely 

 attached to Pyriformis. The outer surface has a 

 well-marked oblique ridge for the tendon of 

 Gluteus medius, which takes the whole breadth of 

 the ridge. Above and behind this marking may 

 run into that for Pyriformis, when the muscles 

 are partly fused, and in front it is continuous with 

 the lower end of the minimus insertion : these two 

 Glutei are usually fused along their front borders, 

 and it is evident that the fused parts, lying in 

 front of the level of the joint, have similar action as internal rotators. 



Above the oblique ridge the trochanter is covered by medius with an intervening 

 bursa, and is thus moulded to a direction differing from that of the bone below the 

 ridge, which is covered only by maximus : this lower surface may have a bursa lying 

 on it, but as a rule the bursa only reaches its most prominent part. The posterior 

 surface is also directly covered by maximus, so that it forms a continuous curve with 

 the area below the oblique ridge. 



Obturator externus is not concerned in forming the overhanging trochanter, so 

 that the epiphysial line, which goes to the bottom of the digital fossa (Fig. 118), is 



FIG. 117. Upper aspect of head, neck 

 and great trochanter of right 

 femur. 0. Obturator internus 

 insertion ; P. Pyriformis inser- 

 tion. The area of insertion of the 

 fibres of the superior retinaculum 

 is marked at x, and it is seen to be 

 continuous with that of Pyri- 

 formis round the front of O. and 

 to extend on the neck further than 

 the epiphysial line. Compare with 

 Fig. 118. 



