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.
Pectoralis Major. These are the two large chest muscles primarily the pushing muscles of the upper body. It makes up most of the upper body. As you raise and lower your body during a push-up, the pectoralis major is doing most of the work to raise and lower your body.