FEMUR. 



1G3 



Fig. 106. Plan of the Development of the Femur. 

 By 5 Centres. 



Appears a 



Ajytearsat end 'fl*y? 

 'Joins Shaft a&out l&?y l 



Joins S/itiftalout 18* y? 



upper end (fig. 105), they run in parallel columns a a from the summit of the head 

 to the thick under wall of the neck, while a series of transverse fibres b b decus- 

 sntos the parallel columns, and connects them to the thin upper wall of the neck. 

 Another series of plates c c springs from the whole interior of the cylinder above 

 the lesser trochanter ; passing upwards, they converge to form a series of arches 

 beneath the upper wall of the neck, near its junction with the great trochanter. 

 This structure is admirably adapted to sustain, with the greatest mechanical 

 advantage, concussion or weight transmitted from above, and serves an important 

 office in strengthening a part especially liable to fracture. 



In the lower end, the cancelli spring on all sides from the inner surface of the 

 cylinder, and descend in a perpendicular direction to the articular surface, the 

 cancelli being strongest, and having a more decided perpendicular course, above 

 the condyles. 



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



Development (fig. 106). The 

 femur is developed by Jive centres ; 

 one for the shaft, one for each ex- 

 tremity, and one for each trochanter. 

 Of all the long bones, it is the first 

 to show traces of ossification: this 

 first commences in the shaft, at 

 about the fifth week of foetal life, 

 the centres of ossification in the 

 epiphyses appearing in the follow- 

 ing order : First, in the lower end 

 of the bone, at the ninth month of 

 foetal life; from this the condyles 

 and tuberosities 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 thir- 

 teenth and fourteenth. The order 

 in which the epiphyses are joined 

 to the shaft, is the direct reverse 

 of their appearance ; their junction 

 does not commence until after 

 puberty, the lesser trochanter being 

 first joined, then the greater, then 

 the head, and, lastly, the inferior 

 extremity, the first in which ossi- 

 fication commenced, which is not 

 united until the twentieth year. 



Attachment of Muscks. To the great trochanter: the Gluteus medius, Gluteus 

 minimus, Pyriformis, Obturator interims. Obturator externus, Gemellus superior, 

 Gemellus inferior, and Quadratus femoris. To the lesser trochanter : the Psoas 

 magnus, and the Iliac us below it. To the shaft : its posterior surface ; the Vastus 

 externus, Gluteus maximus, short head of the Biceps, Vastus internus, Adductor 

 magnus, Pectineus, Adductor brevis, and Adductor longus ; to its anterior surface; 

 the Crureus, and Subcrureus. To the condyles: the Gastrocnemius, Plantaris, 

 and Popliteus. 



THE LEG. 



The Leg consists of three bones : the Patella, a larg%gesanioid bone, placed in 

 front of the knee ; the Tibia, and Fibula. 



Joins SJia;flafW*u r . 



