(2) Complementary cycle. Over a period of time, quiet breathing may not
totally satisfy the oxygen requirements of the body. Thus, we can observe a breathing
cycle with a slightly greater volume exchange called the complementary cycle. It
provides a little extra oxygen to make up the difference.
(3) Forced breathing. In forced breathing, the volumes of air exchanged are
much greater than in quiet breathing. The actual volume exchanged depends upon the
(4) Holding of breath. One can inhale a volume of air and hold it for a period.
If one makes an exhalation effort but still holds the air inside the lungs, it is called
Valsalva's maneuver (forced expiration against a closed glottis).
(5) Cough. If one suddenly releases the air, terminating Valsalva's
maneuver, the result is a cough. If the musculature of a patient's abdominal wall is
paralyzed, the patient cannot execute the Valsalva's maneuver and cannot produce a
(6) Speech. During speech or vocalization, the breathing cycles overlap.
That is, the subsequent cycle begins before the previous one is ended. The purpose of
this is to maintain a continuous outflow of air.
Section III. COSTAL ("THORACIC") BREATHING
Costal breathing is breathing accomplished by moving of the rib cage as a whole.
7-11. ANATOMY OF THE HUMAN RIB CAGE
The rib cage is made up of 12 pairs of ribs, 12 thoracic vertebrae, and the
(1) Structure of a "typical" rib. Each rib is a flat-type bone that is curved
laterally. Along its inferior margin is a subcostal groove.
(a) All 12 pairs of ribs are attached posteriorly to the thoracic vertebrae.