158 ADOLF H. SCHULTZ 



ascertain, namely as the most distal point of the insertion on 

 the tuberositas deltoidea (fig. 1, point VI). The most proximal 

 point of insertion is frequently concealed by the body of the mus- 

 cle and it is necessary therefore to remo\'e it partially. In doing 

 this great care should i^e exercised as the deltoid is usually at- 

 tached at its uppermost end by very delicate strands (fig. 1, 

 point V). The distance between each of these four points and 

 the highest point of the head of the humerus was measured 

 parallel to the axis of the bone, similar to the longitudinal meas- 

 urement of the humerous mentioned above and therefore these 

 measurements are projections. 



The measuring instrument employed was a modified small 

 anthropometer of Martin (Stangenzirkel). This instrument is 

 composed of a ruled metal bar or beam, possessing two arras at 

 right angles to it, one of which is firmly attached to the end, the 

 other movable in the direction of the bar, while both are movable 

 at right angles to the latter. The modification consists merely 

 in the addition of a third arm from another instrument of the 

 same kind, which can also be moved both in the same direction 

 and at right angles to the main axis (fig. 2). 



First one measures the length of the humerus with the two 

 outermost arms of the instrument holding the bar parallel to the 

 axis of the bone, then the middle arm is approximated in turn 

 to the four points of muscle insertion as defined above. This is 

 performed by moving the arm up and down as required, shorten- 

 ing or lengthening it, simultaneously rotating the entire instru- 

 ment around the axis of the humerus if necessary. Readings are 

 taken each time on the ruled bar and correspond with the meas- 

 urements two, three, four and five in figure 1. Indices for the 

 relative position of the middle point of each muscle insertion 

 were obtained b}- the following formulae: 



nieasurcniont 2 + measurement 3 



2 



X 100 lor (he pectoralis major 



measurement 1 



measurement 4 + measurement 5 



measurement 1 



X 100 for the deltoid 



