394 Oil the Angle of the VAhow 



the elbow joint set obliquely to the humerus but also to that of the 

 forearm. As a rule the angles formed by the axis with the humerus 

 and with the forearm are nearly equal, each measuring about 83°, both 

 acute angles pointing outward. The styloid process of the ulna which 

 marks the long axis of the forearm in both pronation and supination, 

 deflects fully 14 degrees from the sagittal axis of humerus when the 

 elbow is extended, and gradually approaches it as the elbow is flexed, for 

 the angles of the humerus and of the forearm neutralize each other in the 

 flexed position. 



This study was made to test these results, and to determine the extent 

 of the motion of the elbow in the European and in the negro, male and 

 female, for during a number of years past I have felt conscious that a 

 sexual difference exists. 



In order to make satisfactory measurements fixed points had to be 

 established and after extending Braune and Kyrklund's reliable method 

 a modified method for measurement was hit upon which when applied 

 repeatedly to the same arm gave an error of less than one degree. Un- 

 fortunately there are more variations than I had anticipated, but I 

 venture to give my data with the hope that they may be of more general 

 use, and that I may be able to add to them in the course of some years. 

 To collect and measure 100 specimens is not altogether a small task, but 

 this kind of work must be multiplied many fold before the foundations 

 of anatomy — descriptive, regional and artistic — become anthropological. 



The arms studied were taken from the dissecting rooms and carefully 

 cleaned, leaving all of the ligaments of the elbow intact. Then the axis 

 of the elbow was determined by fixing the ulna and radius, and moving 

 the humerus to and fro. By doing this it is quite easy to find a point 

 over each epicondyle which does not move. A line extending through 

 these two points passes through the middle of the trochlea and marks 

 the axis of the elbow joint. Frequently there is not an immovable point 

 over one of the epicondyles, but instead a line is determined and in most 

 cases the middle of the line is taken as the axis. Next the humerus was 

 fixed with this axis and' a point in the middle of the upper third of the 

 shaft in a horizontal plane 15 cm. above the plane of the table. The 

 perpendicular plane was then passed through the middle of the upper 

 third of the humerus and through the coronoid process, for it has been 

 shown by Braune and Kyrklund that this process keeps within a milli- 

 meter of this plane, passing first to one side of it and then to the other. 

 The screw motion which is said to be present by Meissner, Henke and 

 Langer does not exist. Five centimeters from this plane a glass plate 

 was fixed from which the measurements were taken. The horizontal 



