In many countries, PAP machines are only available by prescription. A sleep study at an accredited sleep lab is usually necessary before treatment can start. This is because the pressure settings on the PAP machine must be tailored to a patient's treatment needs.
The pectoralis major muscle also performs internal rotation -- turning your arm in toward your body. This action, also called medial rotation, is important for reaching behind your back to tuck in your shirt and combing your hair on the opposite side of your head.
Answer Wiki. The most substantial part of your chest muscle, the Pectoralis major, is best developed through the flat bench press. Hands down, there is nothing better. If you're not doing it you're falling short of your potential progress. In addition to the Pectoralis major, there is a pair of muscles called the Clavicular pectoralis.