84 Anatomy Applied to Medicine and Surgery. 



upper fragment will unite with a supinated lower frag- 

 ment, thus preserving the function of the forearm; and 

 this can be done only by putting the fracture up with 

 splints that will supinate the lower fragment, i.e., with 

 superior and inferior splints. 



Fracture of the shaft immediately below the inser- 

 tion of the pronator radii teres. Here the upper fragment 

 would be flexed by the biceps assisted slightly by the pro- 

 nator radii teres, and would be drawn towards the ulna by 

 the action of the latter muscle, while the lower fragment 

 would be drawn inwards towards the ulna by the pronator 

 quadratus, assisted to some extent by the supinator lon- 

 gus, because the insertion of this muscle into the styloid 

 process would tend to "cant" inwards the upper end of the 

 lower fragment. 



Fracture of the lower end of the radius "Colles' frac- 

 ture" occurs not infrequently in elderly people, females es- 

 pecially, and in this variety of fracture the bone is broken 

 generally about Y% of an inch above its lower articular sur- 

 face. It occurs, as a rule, as the result of a fall On the 

 palm of the hand while the arm is extended. The di- 

 rection of the break is generally transverse, with a slight 

 inclination upwards and backwards. Among the reasons 

 assigned for the occurrence of fracture at the lower part 

 of the radius, are the following : (1) That the compact tis- 

 sue of the shaft meets at this point the cancellous tissue of 

 the lower extremity; (2) That two forces here meet at 

 an obtuse angle, one, being the momentum of the falling 

 body, the other, the vibrations developed by the resistance 

 of the ground to the palm of the hand ; (3) Should a per- 

 son fall on the palm of the hand, with the forearm nearly 

 vertical, the force of impact would be conveyed directly 

 upwards and expend itself among the carpal bones and 

 along the course of the arm, with the possible result of a dis- 



