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.
Understanding pecs. The main job of the chest muscles â the pectorals or pecs â is to push your arms in front of you. They are also used when bringing your arms down from above you. The pectoralis major is a large muscle that attaches to your collarbone, breastbone and ribs.