2s 



JACOB HEIBERG. VON DER DREHUNG DER HAND. 



31. * Petrequin, 



Traité d anatomie médico-chirurgicak. Paris 1844. 



32. * C Gr. Car us, 



Verschiedene Formen (hr Hand. Stuttgart 1846. 



33. *E William Brinton, 



The cyclopaedia of anatomy and physiology. London 1847 — 1849. 

 Vol IV. Part I. P. 230. 



The movement of the lower end of the radius may easily be 

 deduced from the above description, where the shape of the articu- 

 lar surfaces and the attachments of the fibrocartilage alike indicate 

 a rotatory movement of this bone around the ulna; since there 

 is an almost complete correspondence between the apex of the 

 ligament and the centre of that circle of which these articular sur- 

 face would form a part. But although the motion of either of 

 these articulations is thus no very difticult deduction from their 

 anatomy, the mutual consistency of the two, or the movement of 

 the radius as a whole, seems to have been much less understood. 

 The somewhat obscure language in which this has been described 

 would allow us to imagine that a kind of rotation of this bone on 

 its axis was supposed to result as the balance of the movements 

 which obtain at the several joints. This anomalies and inconsi- 

 stencies have been cleared up by Mf. Ward, in his very able work 

 on Osteology; in which he points out that the axes of the head 

 and neck of the radius above, and that of the head of the ulna 

 below (the evident centres of rotation in each case) are continua- 

 tions of each other, and form different portions of one and the 

 same line. which is thus the real axis of the whole bone in its 

 motions. In other words, the axis of the head and neck of the 

 radius, prolonged downwards. would fall upon a point in the lower 

 surface of the ulna, the centre of the circle whereof the sigmoid 

 cavity is a part. And this, he urges. will alone explaiu how the 

 partial rotation of the bone is altogether independent of any antero- 

 posterior movement of its head and occurs ..without disturbance 

 to the parallelism of the superior joint." Thus we might imagine 

 the articulations of the forearm to be the immediate conse<iuence 



