OSTEOLOGY 





They curve outwardly and upwardly to cross in radiating smooth curves to the opposite side. 

 The lower filaments end in the region of the greater trochanter: the adjacent filaments above 

 these pursue a more nearly vertical course and end in the upper portion of the neck of the femur. 

 The trabeculse of this group are thin and with wide spaces between them. As they traverse 

 the space between the medial and lateral surfaces of the bone they cross at right angles the system 

 of curved trabeculse which arise from the lateral (outer) portion of the shaft. (Figs. 247 and 249.) 

 "b. The Principal Compressive Group. This group of trabecula? (Figs. 247 and 249) springs 

 from the medial portion of the shaft just above the group above-described, and spreads upward 

 and in slightly radial smooth curved lines to reach the upper portion of the articular surface of 

 the head of the femur. These trabeculse are placed very closely together and are the thickest ones 

 seen in the upper femur. They are a prolongation of the shaft from which they spring in straight 



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FIG. 248. Diagram of the lines of stress in the upper femur, based upon the mathematical analysis of the right 

 femur. These result from the combination of the different kinds of stresses at each point in the femur. (After 

 Koch.) 



lines which gradually curve to meet at right-angles the articular surface. There is no change as 

 they cross the epiphyseal line. They also intersect at right-angles the system of lines which rise 

 from the lateral side of the femur. 



"This system of principal and secondary compressive trabeculse corresponds in position and in 

 curvature with the lines of maximum compressive stress, which were traced out in the mathematical 

 analysis of this portion of the femur. (Figs. 247 and 250.) 



"B. Lateral (Tensile) System of Trabeculce. As the compact bone of the outer portion of the 

 shaft approaches the greater trochanter it gradually decreases in thickness. Beginning at a point 

 about 1 inch below the level of the lower border of the greater trochanter, numerous thin trabeculae 

 are given off from the outer portion of the shaft. These trabeculse lie in three distinct groups. 



"fi. The Greater Trochanter Group. These trabeculse rise from the outer part of the shaft just 

 below the greater trochanter and rise in thin, curving lines to cross the region of the greater 

 trochanter and end in its upper surface. Some of these filaments are poorly defined. This group 



