96 LABORATORY MANUAL OF ANTHROPOMETRY 



straight arm. It is thus seen that the lateral divergence angle (elbow 

 angle of some authors) is always the sum of the two angles, cubital 

 angle of the humerus and joint-axis angle of the ulna. That of 1 equals 

 154°; of II, 175°; of III, 168°, and of IV, 180°.* 



IV. PROPORTIONS OF THE OLECRANON 



Certain of these, relative to the olecranal cap (Nos. 6 and 7) have 

 already received treatment. There remain now the more usual dimen- 

 sions of length, breadth, and thickness (or depth), with the customary 

 indices to express the relations between them. These are here tabulated, 

 although their value or significance have not yet been proven. 



1 1 . Maximum breadth of olecranon; measured with the sliding com- 

 pass at right angles to the olecrano-coronoid ridge used to define the 

 sagittal plane. 



12. Height of olecranon; measured from the transverse line, groove, or 

 roughness, which runs partly across the concavity of the notch from 

 the outer side, separating the articular surfaces of olecranon and coronoid 

 process, up to the highest point of the olecranon, i.e. the top of the olec- 

 ranal cap. 



13. Thickness (or depth) of olecranon; measured with the sliding 

 compass from volar to dorsal aspects. This is taken across the lip above 

 the notch. 



14. Thickness-breadth index of olecranon (13 : 11) 



_ thickness of olecranon X 100 

 breadth of olecranon 



15. Height-breadth index of olecranon (12 : 11) 



_ height of olecranon X 100 

 breadth of olecranon 



These last two indices have \ielded the following values: 

 H. sapiens: 



Thickness-breadth (14) 



Height-breadth (15) 



Negroes (11; 92 83 



Weddas (3, 96 85 



South Germans, Baden (25) 98 80 



Australians (6) 98 80 



Melanesians (18) 104 88 



Negritoes (6) 107 90 



Fuegians (6) 107 85 



H. primigenius: 



Neandertal 97 86 



Spy 1 92 83 



Spy II 100 86 



* For special studies of the elbow angle see Nagel: Untersuchungen iiber den 

 Armwinkel des Menschen. Zcitschr. Morphol. u. Anthropol., Bd. 10, 1906-07. and 

 Mall: On the angle of the elbow, Amer. Journ. Anat., Vol. 4, 1905, pp. 391-404. 



