228 



SPECIAL ANATOMY OF THE SKELETON 



to this, however, horizontal planes of cancellous tissue are to be seen, so that the spongy tissue in 

 this situation presents an appearance of being mapped out into a series of rectangular areas. 



Articulations. With three bones the os innominatum, tibia, and patella. 



Development (Fig. 1 83). The femur is developed from five centres one for the shaft, one 

 for each extremity, and one for each trochanter. Of all the long bones, except the clavicle, it is 

 the first to show traces of ossification; this commences in the shaft, at about the seventh week of 

 fetal life, the centres of ossification in the epiphyses appearing in the following order : First, in 

 the lower end of the bone, at the ninth month of fetal life 1 (from this the condyles and tuber- 

 osities are formed); in the head at the end of the first year after birth; in the great trochanter, 

 during the fourth year; and in the lesser trochanter, between the thirteenth and fourteenth years. 

 The order in which the epiphyses are joined to the shaft is the reverse of that of their appearance; 

 their junction does not commence until after puberty, the lesser trochanter being first joined, 

 then the great, then the head, and lastly the inferior extremity (the first in which ossification 

 commenced), which is not united until the twentieth year. Because of this late union, the lower 

 extremity of the femur has been called the "growing end" of the bone, and early arrest of ossifi- 

 cation here results in more or less marked diminution of stature. 



Great trochanter. 



-1L - Digital fossa. 



Appears at 4th 

 year; joins shaft ^' 

 about 18th year. ~> 



Lesser 

 trochanter. 



Calcar 

 femorale. 



Appears at 

 9th month 

 (fetal). 



Appears at end 



of 1st year; 



joins shaft about 



18th year. 



Appears lSth-14th year : 

 joins shaft about 18th 

 year. 



Joins shaft at 20th 

 year. 



FIG. 182. Calcar femorale. 



Lower extremity. 



FIG. 183. Plan of the development of the femur, 

 five centres. 



From 



Attachment of Muscles. To twenty-three. To the great trochanter: the Gluteus medius, 

 Gluteus minimus, Pyriformis, Obturator internus, Obturator externus, Gemellus superior, 

 and Gemellus inferior. To the lesser trochanter: the Psoas magnus and the Iliacus below it. 

 To the shaft: the Quadratus femoris, Vastus externus, Gluteus maximus, short head of the 

 Biceps femoris, Vastus internus, Adductor magnus, Pectineus, Adductor brevis, Adductor 

 longus, Crureus, and Subcrureus. To the condyles: the Gastroenemius, Plantaris, and 

 Popliteus. 



Surface Form. The femur is covered with muscles, so that in fairly muscular subjects the 

 shaft is not to be detected through its fleshly covering, and the only parts accessible to the touch 

 are the outer surface of the great trochanter and the lower expanded end of the bone. The 

 external surface of the great trochanter may be felt, especially in certain positions of the limb. Its 

 position is generally indicated by a depression, owing to the thickness of the Gluteus medius and 



1 This is said to be the only epiphysis in which ossification begins before birth; though, according to some 

 observers, the centre for the upper epiphysis of the tibia also appears before birth. 



