OSSIFICATIUX OF THE FEMUR. 



119 



ilium, the tuberosity of the ischium, the anterior inferior spine of the ilium, 

 and the sjTiiphysis pubis. These begin to ossify soon after puberty, and unite 

 with the main bone fi'om the 23rd to the 2r)th year-. 



The jx-lrix of the foetus and young child is of veiy small capacity propor- 

 tionally to the size of the body, and those viscera which are afterwards contained 

 for the most part in the true pelvis occupy a part of the abdominal cavity. The 

 inclination of the pelvis is considerably greater in early life than in the adult. 



The femur is developed from one principal ossific centre for the shaft 

 which appears in the 7th week, and from fom- epiphyses, the centres for which 

 appear in the following order ; — A single nucleus for the lower extremity appears 

 several weeks before bii-th, one for the head appears in the 1st year, one for the 



Fig. 106. 



Fig. 106. — Ossification of the Femur CR. Quain.) 



A, from a fcetus under eight months ; the body is osseous, both ends are carti- 

 laginous. 



B, from a child at birtli, showing a nucleus in the lower epiphysis. 



C, from a child of about a year old, showing a nucleus in the articular head. 



D, at the fifth or sixth year. Ossification has extended from the shaft into the neck, 

 and a nucleus has appeared in the great trochanter. 



E, near the age of puberty, showing more complete ossification and a nucleus in the 

 lesser trochanter. 



1, shaft ; 2, lower extremity ; 3, head ; 4, gi-eat trochanter ; 5, small trochanter. 

 C, D, & E are represented considerably, A and B very little, under the natural size. 



gi-eat trochanter in the 4tli year, and one for the small trochanter in the 13th or 

 14th year. These epiphyses become united to the shaft in an order the reverse 

 of that of their appearance. The small trochanter is united about the 17th year, 

 the great trochanter about the 18th year, the head from the 18th to the 19th year, 

 and the lower extremity soon after the 20th year. The neck of the femur is 

 foiTiied by extension of ossification from the shaft 



The patella is formed in the 3rd month by a deposit of cartilage in the tendon 

 of the qi: i.lriceps extensor cniris muscle. In this cartilage ossification begins 

 fi'om a single centre during the thii-d year, and is completed about the age of 

 puberty. 



The tibia and fibula each present, besides the principal centre of ossification 

 for the shaft, a superior and an inferior epiphysis. In the tibia the centre for 

 the shaft appears in the 7th week ; that for the upper extremity, including the 

 anterior and lateral tuberosities, appears most frequently before, but sometimes 

 after bii-th ; and that for the inferior extremity and internal malleolus appeal's 



