Do you have pain in your shoulder when you comb your hair, brush your teeth or reach behind your back? If it also hurts down the front and side of your arm you may have a problem with your infraspinatus muscle. The infraspinatus runs from the lower half of the scapula to the head of the humerus (the upper arm). Pictured below its primary function is to allow you to move your arm laterally. It is one of the four rotator cuff muscles. The others are supraspinatus, tere minor and subscapularis. Together these four muscles hold your arm into a socket of your scapula and allow you to rotate your arm and make throwing motions. When a shoulder is dis-located one of these four muscles is involved along with damage to the shoulder joint capsule and cartilage.
The infraspinatus muscle can be treated by massaging along the length of the muscle fibers as well as going cross fiber (across the fibers). Trigger point therapy and myofascial release techniques are also helpful. It is also important to treat surrounding muscles that work with the infraspinatus.
Information provided by www.stevebotuchis.com