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.
The pectoralis major is a powerful chest muscle that causes the arm to rotate inward and move closer to the body. It can also help move the arm forward or backward. The muscle originates from two points: the sternum (breastbone) and the clavicle (collarbone).