The shoulder is an incredibly mobile joint. You can rotate your arm in every direction. Think of what it takes to throw a baseball; your arm is lifted and rotated behind your ear and then accelerates forward propelling the baseball. After letting go of the ball the arm is slowed down by other the shoulder muscles in a controlled fashion. Throwing a ball is a complicated event involving more than 10 muscles contracting to accelerate the arm and then slow it down.
People commonly hear friends complain of a rotator cuff sprain. The rotator cuff is made up of four muscles that stabilize the humeral head as it attaches the scapula: infraspinatus, teres minor, supraspinatus, and subscapularis muscles. The muscles work together to control the humerus rotational movements. The supraspinatus muscle is the one that is most commonly injured during exercise and daily life. So when people say they have a rotator cuff sprain, they are usually referring to supraspinatus sprains or tendinosis.
Two of the rotator cuff muscles are on the back of the shoulder, one is on the top, and one attaches to the front. The infraspinatus muscles and teres minor are on the back of the shoulder. The muscles start on the scapula and run toward the humerus. The muscles extend the upper arm and also help to slow it down during throwing motions. Injuries can affect the muscles anywhere from the scapula to the humerus insertion. Two muscle injuries are more common in the infraspinatus, either in the middle of the muscle belly or attachment at the humerus.
The subscapularis muscle starts on the front of the scapula and attaches on the humerus. It is a major stabilizer of the humerus, which allows the arm to undergo its incredible rotation movements. Injuries to the muscle do not often cause direct pain. Instead the muscle becomes injured and doesn't function to stabilize the humerus, leading to injuries in other tendons. Pain in the front of the shoulder could also be from the pectoralis major or latissimus dorsi insertions, or bicep muscle origin.
The supraspinatus muscle begins on the top of the scapula runs toward the tip of the shoulder. The muscle's tendon is usually injured from eccentric overload, affecting its stabilization function of the humerus. The tendon is usually injured at its attachment to the greater tubercle, or top of the arm bone. This muscle is the most commonly injured and inflamed, which may occur when the tendon is "squished" between the scapula and humerus.
Initial treatments of any tendon injury involve decreasing pain and intensity. Massage therapy works to decrease muscle hypertonicity and spasms. A trained massage therapist will address pain and muscle spasms in all the muscles that affect shoulder movements, including rotator cuff muscles, deltoid, pectoralis major, pectoralis minor, trapezius, latissimus dorsi, bicep, and rhomboids. Ice can also help to decrease the pain and inflammation.
All the shoulder muscles work together to move your arm above
your head or behind your back. Usually when a friend tells
stories of hurting their rotator cuff or undergoing rotator
cuff surgery, they are referring to the supraspinatus tendon,
which may have been hurt as a result of other muscles not
doing their job to stabilize the shoulder. Working on increasing
the strength and endurance of all the shoulder stabilizers
will assist in preventing future injuries.