158 



ELEMENTS OF PHYSIOLOGY 



ribs upward and outward (Fig. 140). (Place the hands at 

 the sides of the waist while inspiring, and this will be 

 noticed.) The inner muscles increase these spaces when 

 they contract, and thus depress the ribs and aid in expira- 

 tion (Fig. 137). In active expiration the abdominal walls 

 contract and press the abdominal organs against the dia- 

 phragm. By feeling the body, find the location of the 

 muscles that contract during strong expiration. Feel the 

 same muscles during the act of coughing. 



263. THOUGHT LESSON. Ease in Breathing. By study- 

 ing the skeleton of the chest (Figs. 59, 141), carefully 

 observing the bones and cartilages, and by experimenting 

 upon his or her own breathing, the pupil is to fill out the 

 following reasons why expansion and contraction of the 

 lower chest ("waist breathing") is easier than breathing 

 with the upper chest (" collar-bone breathing "). 



1. There are two pairs of 



ribs below, while there are none 

 above. 



2. There are three pairs of 



ribs below, while there are none 

 above, but all the ribs of the upper 

 chest are ribs. 



3. The joints between the seven 

 pairs of true ribs and the sternum 



are more flexible below because . 



(Observe carefully Figure 141.) 



4. In waist breathing the breaths 



will not have to be so frequent to supply the same amount 

 of air, because the lower chest, besides being more flex- 

 ible, is than the upper chest. 



5. The walls of the waist swing - - and while the 



walls of the upper chest must move - - and - . 



6. The bones of the rest upon the upper chest. 

 In upper chest breathing their weight, and the weight of 



FIG. 141. 



