100 OSTEOLOGY, OR ANATOMY OF OSSEOUS SYSTEM 



becomes rounded at its summit, and enlarged as it joins the 

 head. It is shorter above and in front than below and behind. 

 Posteriorly it usually shows a shallow groove for the obturator 

 externus tendon. Its junction with the shaft behind is marked 

 by the posterior intertrochanteric line. The capsule of the 

 hip-joint is attached to the neck about half an inch internal 

 to and above this line. 



The head is joined to the shaft by the neck. It forms more 

 than a half-sphere, and articulates with the acetabulum. A 

 little below and behind the centre of its surface is a depres- 

 sion (fossa capitis), the forepart of which gives attachment 

 to the interarticular ligament (ligamentum teres) of the joint. 

 In this hollow are one or two vascular foramina. 



The great trochanter (to turn) is a thick process prolonged 

 upward in a line with the external surface of the shaft to a 

 level about ^ or f inch below the head. In front it is marked 

 by a broad depression for the gluteus minimus. Externally 

 an oblique line runs downward and forward, indicating the 

 inferior border of the gluteus medius insertion. Lower down 

 is a horizontal line continued to the tubercle of the femur, which 

 is situated in front at the junction of the neck with the great 

 trochanter; the tubercle is the meeting-place of five muscles 

 vastus externus, gluteus minimus, obturator internus, and 

 two gemelli. Internally, at the base of the trochanter and 

 rather behind the neck, is the digital fossa, giving attachment 

 to the obturator externus tendon. Above and in front of 

 this is the insertion of the obturator internus and gemelli 

 muscles. 



The upper border of the trochanter is narrow, and presents 

 an oval mark for the pyriformis. The posterior border is 

 prominent, and continuous with the posterior intertrochanteric 

 line, limiting the neck posteriorly. Above the centre of this 

 line is the tubercle of the quadratus, for attachment of the upper 

 part of the quadratus femoris; sometimes a linea quadrati 

 passes vertically down from the tubercle. 



The small trochanter is a pyramidal eminence projecting 

 inward and backward from the posterointernal aspect of the 

 bone at the junction of the neck with the shaft. Its apex 

 gives attachment to the iliopsoas tendon. 



Anteriorly the neck is separated from the shaft by the (inferior 

 intertrochanteric line, which is the upper part of the spiral 



