258 A MANUAL OF ANATOMY. 



to the condyles of the humerus in the normal state that 

 must be kept in mind : 



(1) When the forearm is extended on the arm, the top 

 of the olecranon and the two condyles are all in the same 

 straight line. 



(2) If the forearm is flexed to a right angle with the 

 arm, the condyles and the tip of the olecranon are in the 

 same plane. The coronoid process of the ulna may be 

 found in front of the inner part of the elbow on deep pres- 

 sure. It is usually not easily distinguished. The head 

 of the radius will be felt, on rotation of the shaft, three- 

 fourths of an inch below the external condyle. The 

 "carrying angle : " This is the normal angle (10) formed 

 by the arm and the supinated forearm ; its opening is out- 

 ward. It is produced by the trochlear surface of the 

 humerus being prolonged lower on the inside than outside 

 and thus throwing the lower end of the ulna outward. 

 The angle may be lost in fractures involving the condyles 

 of the humerus and should always be restored ; if not 

 maintained, a peculiar deformity gun-stock remains. 



The shafts of the ulna and radius terminate below in 

 their respective styloid processes. Demonstrate that the 

 styloid process of the radius is about one-fourth of an inch 

 lower than that of the ulna. If this relation is altered so 

 as to bring the processes in the same line it shows that a 

 fracture of one or the other bones has occurred. In the 

 reduction of the usual (Colles's) fracture of the wrist see 

 that the normal relation is reproduced. 

 Outlining- the Heart and Lungs. Figs. 57, 58, 59. 



The student now should take time to mark out the super- 

 ficial outlines of the heart, lungs, and great vessels upon 

 the exterior of the chest. The relations of the heart given 

 below are the results of the writer's own investigations in 



