Charles E. Bardoon 287 



"neck/' Similar conditions have heen pictured l)v TTason, oo, for the 

 His embryo So, length 17 mm. 



In Embryo XXII, Iciu/th' 20 mm.. Figs. 9 and 10, the head of the 

 feinnr is proportionately larger and between it and the great trochanter 

 the cartilage has developed in snch a way as to give rise to a short neck. 

 Blastemal extensions serve to give attachment to the musculature of the 

 hip and indicate the lesser trochanter and the intertrochanteric ridge. 

 In Embryo CXLV, length 33 m.m.. Figs. 11 and 13, the cartilage has 

 extended into these projections and the main characteristics which dis- 

 tinguish the proximal end of the femur have become established. Even 

 at this stage, however, the neck is proportionately very short and thick. 

 In an embryo of 50 mm., LXXXIV, Fig. 13, the neck is relatively more 

 slender and the head of the femur has become more rounded. 



The hip-joint is represented at first by a dense mass of scleroblastema, 

 Fig. 55. The development of the acetabulum by ingrowth and fusion 

 of processes from the iliac, ischial and pubic cartilages has already been 

 described. The cartilagenous joint-cavity is at first quite shallow, Fig. 

 56. But extension of cartilage into the blastemal tissue which passes 

 from the pelvis over the head of the femur serves greatly to deepen it 

 on all sides except in the region of the cotyloid notch. 



The joint-cavity is at first completely filled with a dense blastemal 

 tissue. Fig. 56. While the embryo is growing from 20 to 30 mm. in 

 length cavity formation begins in the tissue lying between the cartilage- 

 nous floor of the acetabulum and the head of the femur. The first stage in 

 the process is marked by a condensation of the capsular tissue immedi- 

 ately bordering upon the joint and of the perichondral tissue which at 

 this stage covers the cartilages on their articular surfaces as well as 

 elsewhere. In the region of tlie ligamentum teres a fibrous band is like- 

 wise differentiated from the blastema of the joint. The rest of the tissue 

 becomes looser in texture and ultimately is absorbed. Fig. 57. Henke 

 and Reyher, 74, gave a good account of the development of the hip-joint. 

 Moser has discussed the ligamentum teres. 



The shaft of the femur at the stages of Embryos CIX and CXLIA^, 

 Figs. 3, 4, 5 and 6 is proportionately very short and thick. For a time 

 it then grows so rapidly that it may become distorted and bent from the 

 resistance offered at each end. But soon adjustment takes place between 

 the skeletal and the neighboring parts and the femur becomes straight 

 and slender. Yet in Embryo CXLV, length 33 mm.. Figs. 11 and 12, 

 it is relatively thicker than in the adult. 



The linea aspera is marked during the early development of the femur 

 by a thickening of the pericliondrium in the region where the various 



