The Lower Extremity and Pelvis 



side. Careful estimation of its relative position and level is most useful in differen- 

 tial diagnosis of lesions in the neighbourhood ; its upper extremity just touches, nor- 

 mally, a line drawn between the tuber ischii and the anterior superior iliac spine 

 (Nelaton's line), and a higher position on one side 

 points to lessening of the vertical difference between 

 the acetabular and trochanteric levels. The top of 

 the trochanter is about on a level with the middle 

 of the acetabulum. The rounded head of the bone 

 lies in its joint behind the Psoas, where its mass can 

 be felt, or its absence ascertained in states associated 

 with such a condition. The joint lies about the 

 centre of the line drawn from the pubic spine to the 

 trochanter when the limb is not too much everted. 

 The side aspects of the two condyles can be easily 

 examined, covered by relatively thin aponeuroses. 

 It should be remembered that the front and lower 

 parts of these aspects of the condyles are covered by 

 lateral recesses (Fig. 122) of the synovial sac ; this 

 moves down with the patella when the leg is flexed, 

 a fact utilised under certain surgical circumstances. 

 The adductor tubercle can be felt on the upper part 

 of the inner prominence, and the external lateral 

 ligament is distinctly recognised on the outer side 

 on bending the knee. The lower edges of the 

 condyles, if not found at first, can be placed at once 

 on flexion, and their front aspects can be examined 

 to some extent by relaxation of the extensors and 

 side-to-side movement of the patella. 



FIG. 125. Scheme to illustrate the 

 structure of the femur. The shaft 

 is a hollow bony cylinder in the 

 middle, but has cancellous tissue 

 at the ends ; this is dense in the 

 trochanter, a, but does not show 

 any particular arrangement here, 

 but this is not the case in the 

 head, neck, and lower end, in the 

 lines of weight -transmission. In 

 the lower end there is a tendency 

 to formation of vertical lamellae, 

 b, with cross-lamellae near the 

 surfaces, c. In the neck there are 

 spiral lamellae in the plane of the 

 shaft wall, giving an appearance 

 of arcades on section, and con- 

 tinued into dense cancellous bone 

 in the head. Observe that the 

 weight, w, will be transmitted 

 from the upper part of the 'head 

 through these spirals- to the lower 

 wall of the neck ; here the wall is 

 accordingly thick and noticeable 

 on section, and is termed the 

 calcar femorale. 



the small trochanter at twelve or thirteen. Fusion 



of the head epiphysis with the neck, which has become longer, occurs at about 

 eighteen, and the trochanteric epiphyses join the shaft about the same time or a little 

 earlier. The bony lower end remains distinct until twenty-three or twenty-four, 

 when its epiphysial line ossifies ; so the lower is the growing end of the bone. 



The occasional centre for the gluteal ridge has already been mentioned 



(P- 147)- 



The rough linea aspera becomes apparent at out puberty. ( * 



Ossification of Femur. 



The bone is represented by a short and thick 

 cartilaginous rudiment, in which ossification com- 

 mences, at the centre of the future shaft, towards the 

 end of the second month or earlier. 



At birth the shaft is bony and the neck is 

 short, while the trochanters and the extremities are 

 in cartilage ; in the lower end, however, there is 

 usually a small ossific centre in the depth of the 

 cartilage, but this may not appear till just after 

 birth. 



The centre for the head appears in the first 

 year, that for the great trochanter at three, and for 



