20 LANDMARKS MEDICAL AND SURGICAL. 



often difficult to count the ribs ; hence the following rules 

 may be useful : 



a. The finger passed down from the top of the sternum 

 soon comes to a transverse projection, slight, but always to 

 be felt, at the junction of the first with the second bone of 

 the sternum. This corresponds with the level of the cartilage 

 of the second rib. 



b. The nipple of the male is placed, in the great majority 

 of cases, between the fourth and the fifth ribs, about three- 

 quarters of an inch external to their cartilages. 



c. The lower external border of the pectoralis major 

 corresponds with the direction of the fifth rib. 



d. A line drawn horizontally from the nipple round the 

 chest cuts the sixth intercostal space midway between the 

 sternum and the spine. This is a useful rule in tapping the 

 chest. 



e. When the arm is raised, the highest visible digitation of 

 the serratus magnus corresponds with the sixth rib The 

 digitations below this correspond respectively with the seventh 

 and eighth ribs. 



f. The scapula lies on the ribs from the second to the 

 seventh, inclusive. 



g. The eleventh and twelfth ribs can be felt even in 

 corpulent persons, outside the erector spinae, sloping down- 

 wards. 



//. One should remember the fact that the sternal end of 

 each rib lies on a lower level than its corresponding vertebra. 

 For instance, a line drawn horizontally backwards from the 

 middle of the third costal cartilage at its junction with the 

 sternum, to the spine, would touch the body, not of the third 

 dorsal vertebra, but of the sixth. Again, the end of the 

 sternum would be on about the level of the tenth dorsal 

 vertebra. Much latitude must be allowed here for variation 

 in the length of the sternum, especially in women. 



39. Interval below clavicle. Immediately below the 

 clavicle we recognise the triangular interval between the 

 pectoralis major and the deltoid. This space varies in 

 different cases, depending on the distance between the 



