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. The petoralis major is a large, strong muscle that produces shoulder flexion. It is located in the front of the chest and attaches by tendon to the humerus, or upper arm bone.ectoralis Major. The petoralis major is a large, strong muscle that produces shoulder flexion. It is located in the front of the chest and attaches by tendon to the humerus, or upper arm bone.