The rotator cuff is a group of four muscles that help to support the shoulder joint. They also provide a wide range of shoulder movement, allowing the arm to be used in a variety of ways. The muscles of the rotator cuff are the supraspinatus, the infraspinatus, the teres minor and the subscapularis. Each of these muscles originate on the scapula, or shoulder blade, and attach to the humerus, or upper arm. Researcher O. Opsha and colleagues, writing in the October 2008 "European Journal of Radiology," explain that damage to the rotator cuff is a fairly common occurrence that can be due to either repetitive motions or acute injury. An orthopedic surgeon can perform a procedure to repair the rotator cuff and restore function to the shoulder joint. In the early stages of healing following the repair, the arm is placed in a sling and certain shoulder movements are restricted until the muscles heal enough to allow active motion.
Shoulder Abduction
The movement of shoulder abduction, or moving the arm out to the side and away from the body, is performed in part by the supraspinatus muscle. The supraspinatus begins the motion of abduction and helps to stabilize the shoulder joint so that the deltoid muscle can take over and perform the remainder of the abduction movement. Because the supraspinatus begins the movement, shoulder abduction is restricted in the early stages of postsurgical recovery to allow the repair site to mend and to avoid tearing this muscle again.
External Rotation
The two muscles that work to turn the shoulder outwards are the infraspinatus and the teres minor. Many rotator cuff injuries that involve these muscles result from damage caused by excessive rotational forces .External rotation of the shoulder should be avoided in the initial healing phase to reduce stress on these muscles. The shoulder rotates outward during such activities as brushing the hair and throwing a ball.
Internal Rotation
Internal rotation of the shoulder is performed by the subscapularis muscle. While this muscle is not the most commonly damaged among the four that constitute the rotator cuff, prevalence of subscapularis tears approaches 30 percent, according to J.R. Barth and colleagues, writing in the October 2006 edition of the journal "Arthroscopy." The motion of placing the hand behind the low back or the forearm across the abdomen is internal rotation of the shoulder. After repair, the arm is typically placed in some measure of internal rotation in the sling. Physicians direct patients not to actively turn the arm further inward to avoid strain at the surgical site.
Duration of Mobility Limitations
Most orthopedic surgeons limit the active motions of shoulder abduction, internal and external rotation for the first six weeks of the recovery period. After the rotator cuff has had time to heal, the doctor prescribes special exercises or refers the patient to a physical therapist to continue the rehabilitation process. With rehabilitation, most people who have had a rotator cuff repair are able to regain functional use of the extremity and can move the shoulder joint without pain.
References
- "European Journal of Radiology"; MRI of the Rotator Cuff and Internal Derangement; O. Opsha, A. Malik, R. Baltazar, et. al.; October 2008
- "Journal of Orthopedic Research"; The Effect of Rotator Cuff Tears on Reaction Forces at the Glenohumeral Joint; I.M. Parsons, M. Apreleva, F.H. Fu, et. al.; May 2002
- "Arthroscopy"; The Bear-Hug Test: A New and Sensitive Test for Diagnosing a Subscapularis Tear; J.R. Barth, S.S. Burkhart, J.F. DeBeer; October 2006
