234 A MANUAL OF ANATOMY 



third is therefore extracapsular, and at its outer part it presents a 

 horizontal groove which leads to the digital or trochanteric fossa, 

 and lodges the tendon of the obturator externus. The superior 

 aspect forms a short, almost horizontal border, which has a slight 

 inclination downwards to the great trochanter. The inferior 

 aspect forms a long, concave border, ending inferiorly at the small 

 trochanter. 



The neck is pierced by numerous nutrient foramina, which are 

 more abundant and of larger size above and behind than else- 

 where. 



The head and neck receive their blood-supply from the obturator, 

 sciatic, and external and internal circumflex, arteries. 



The great trochanter is a quadrilateral eminence continuous with 

 the outer surface of the shaft. It presents three surfaces and four 

 borders. The external surface is marked by an oblique impression 

 which extends from the postero-superior to the antero-inferior 

 angle, and gives insertion to the gluteus medius. The anterior 

 surface presents, towards its lower part, an impression for the 

 insertion of the gluteus minimus. The internal surface at its lower 

 part presents the digital or trochanteric fossa for the insertion of 

 the obturator externus, whilst above and in front of this it affords 

 insertion to the obturator internus and gemelli. The superior 

 border, which is almost horizontal, meets the posterior border at 

 a right angle, the pointed projection thus formed being called the 

 postero-superior angle. Near the centre of this border there is an 

 oval impression for the insertion of the pyriformis. The inferior 

 border gives origin to fibres of the vastus externus. The anterior 

 border skirts the front of the great trochanter, and ends above at 

 the superior cervical tubercle. It also gives origin to fibres of the 

 vastus externus. The posterior border is prominent and con- 

 tinuous with the posterior intertrochanteric line, the quadrate 

 tubercle being situated at the junction of the two. The great 

 trochanter is pierced by several nutrient foramina. 



The small trochanter is a conical projection which springs from 

 the posterior and inner aspects of the bone where the neck and 

 shaft join. It -gives insertion to the ilio-psoas, some of the fibres 

 of the iliacus being inserted below and in front of it, where there 

 is a depressed triangular surface lying between the prominence 

 and the spiral line. 



The trochanters receive their blood-supply from the circumflex 

 arteries. 



The shaft is longitudinally curved, the convexity being directed 

 forwards. Its girth is least at the centre, and it expands at 

 either end, more especially the lower. It is triangular in section 

 in the middle third, the lateral angles being rounded off, and the 

 posterior, formed by the linea aspera, prominent. Over its upper 

 and lower thirds it is somewhat subcylindrical. The posterior 

 aspect presents over its middle third a bold ridge, called the linea 



