Well your heart is used for breathing it's a cardiac muscle by the way :-()
These would be the abdominal muscles.
Breathing out in crocodiles is a passive process. As the muscles used for inhalation relax, the chest cavity naturally decreases in size causing air to be expelled from the lungs. Crocodiles do not have a diaphragm like mammals to actively control their breathing.
Breathing is the process that would be adversely affected, as these muscles contract and relax when you breathe in and out.
Diaphragm
On average, humans use about 5-10% of their daily energy expenditure on breathing. The energy is mainly used for the muscles involved in the breathing process and to warm, filter, and humidify the air we breathe.
Muscles are used for picking things up, breathing, seeing, and/or doing a physical activity, such as walking.
external intercostals and the diaphragm
Ribs are for protection i think and diaphragm is the muscle controlling inhaling and exhaling. Also: the rib muscles can help the breathing process, which is useful when the diaphragm is weak, constricted, or to get an extra-big breath. Breathing from the diaphragm makes the belly move in and out as the lungs extend downwards. Breathing from the rib muscles makes the chest expand and rise.
The diaphragm, the external intercostal and the interchondral portion of the internal intercostal muscles are the main muscles that control breathing. Other muscles are sometimes used, but only if the person has a breathing disorder or if the body needs energy very quickly.
These are diaphragm and externa intercostal muscles in quiet breathing and sternocliedomastoid ,sclene muscles,anterior serrati in heavy breathing
1. diaphragm 2. external intercostal muscles 3. internal intercostal muscles (only in forceful exhalation such as coughing not relaxed breathing)
Breathing. These muscles are used to change the pressure in the chest so air can flow in and out of the lungs (on inspiration and expiration).