94 



LABORATORY MANUAL OF ANTHROPOMETRY 



result. Of much greater significance is the angle expressing the relation 

 of the plane of motion of the elbow joint to the longitudinal axis of the 

 shaft, which can be ascertained with some accuracy from such a pro- 

 jection, the joint axis angle. 



9. Joint-axis angle. To determine this first draw upon a given volar 

 projection the line AE (Fig. 34), coincident with the curved longitudinal 



II 



FIG. 34. Ulna of I, White (So. German), and II, Negro, to compare the joint-axis angle 



in the two. (After Fischer) . 



ridge of the greater sigmoid notch, which is used in determining the lateral 

 plane. This marks the plane along which the forearm moves in flexion 

 and extension. Next draw a perpendicular across this at any convenient 

 place with the limits of the notch, as CD, and this line, which is perpen- 

 dicular to the plane of rotation, must necessarily be parallel to the axis 



