Rotator Cuff

The shoulder Joint consists of 3 bones- the upper arm (the humerus) the shoulder blade (the scapula) and the collarbone (the clavicle). The humerus and scapula form a “ball and socket” joint. With a shallow socket and large ball, the shoulder is very mobile joint, but not a very stable one. Therefore, the shoulder relies heavily on different types of soft tissue to hold it together. The innermost layer of tissue holding the shoulder together is the labrum. The labrum acts as sort of a “gasket” attached around the rim of the socket. It increases the contact area between the ball and socket to improve stability. Moving outward from the inside of the joint, the next stabilizing tissue in the shoulder is the joint capsule. The capsule is made up of a series of ligaments that hold the ball and socket together. To do its job effectively. The capsule must be tight enough to keep the joint together but loose enough to allow for full range of motion. It is actually the capsule that determines how far the shoulder joint is able to move.

Secondary (internal) Impingement is compression of the rotator cuff tendons between the humerus and the back (posterior) aspect of the glenoid socket. In the case of a secondary impingement, the shoulder joint is often loose or unstable. The ligaments of this joint do not do an efficient job at holding the humerus in the socket. Consequently, in certain positions, the head of the humerus can migrate forward (anteriorly) and cause a trapping phenomenon of the rotator cuff tendons in the back of the shoulder joint. This type of impingement is seen more often in a population of individuals who have loose joints or what is often clinically referred to as joint instability.

Unfortunately, the rotator cuff muscles are small and do not have great endurance. If you do an overhead activity like swimming, or pitching over and over, the muscles get tired. The more fatigued they become, the more trouble they have holding the bones apart. Then you fall into the trap. Since the rotator cuff tendons are between two bones, they begin to rub. As they rub, they get irritated. As they get irritated the muscles lose strength. Since their job is to prevent the bones from rubbing together in the first place, you can see the problem. You are injuring the muscles that need to act as a safety device.

That is easy, you say. If it hurts, I will stop. Unfortunately, it is not that simple. When tendons begin to get irritated, you usually don’t know it. There is enough blood flowing to the area warm and prevent significant swelling, so you keep going. When you hit the danger spot of either too much swelling, or too much damage to the tendons, it is too late. Now even rest may not be enough.

Another way to injure the cuff is simpler. A fall or hit to the shoulder drives the bones together. The force traps the rotator cuff tendons and injures them. The rotator cuff can no longer function to separate the joint and the injury gets worse. This describes a traumatic rotator cuff “tendonitis”. The tendon is the end of the muscle. A rotator cuff tear occurs when there is enough force or enough stress of a long period of time to significantly tear the muscles or tendon apart. This is more serious and surgery may be required to repair the tear.

A related injury is shoulder bursitis. The bursa is a small sac of fluid that sits on top of the rotator cuff tendons. Its job is to be a cushion between the tendons and the bone. Theoretically, this would always prevent injury. But many times the bursa breaks down. This can be extremely painful and makes any shoulder movement hard.

A major reason for the frequencies of these injuries is muscle imbalance. We tend to have strong front muscles and less developed back muscles. The front muscles (pecs, delts, and lats) get strong with sports, jobs, and household chores because almost everything we do is in the front of us. The pitcher reaches back slowly, but then fires his arm forward. The assembly line worker and the computer operator have to reach in front all day long.

Then we decide to work out. So we use weights and Nautilus, and sure enough, we make the front muscles even stronger. Most weight programs do little for the back muscles compared to muscles in the front of the trunk. We consider it working if we can look in the mirror and see our chest and biceps bulging. Meanwhile, we ignore our rotator cuff. No wonder these muscles get tired. This imbalance may also be adding to our frequency of neck and upper back strains, or other shoulder injuries. For years, baseball pitchers worked on strengthening their chest muscles instead of their rotator cuffs… for years, pitchers had career ending rotator cuff injuries.

So how do you prevent this? One way is to avoid excessive overhead activities (i.e. painting a ceiling, throwing a ball, wallpapering, exercising by lifting weights overhead) Look at these examples:

“Miss Jenna” watches a tape and decides to do aerobics for the first time with hand-weights. She has never done any upper-body strengthening. She does 40 straight minutes of exercise with repeated overhead lifting. She feels great, but two weeks later wakes up with pain in her shoulder.
“Pistol Pete” has to get his seven trees pruned prior to his barbecue. His is out in the yard to eight hours. During the weeks he works at a desk and begins to notice pain every time he has to reach for the phone.
“Rocket Ron” is a star relief pitcher. He pitches two innings on Saturday and three on Sunday. He is supposed to rest on Monday, but it is a close game and they decide to have him pitch four innings. Near the end he hears a pop, and grabs his shoulder in severe pain.

It is no wonder why these people start complaining of pain. They overdid it. The first muscle group to fail is the rotator cuff. It can’t continue to keep the shoulder bone from riding up into the shoulder cap. The tendons begin to get irritated or in severe cases, it ruptures. The irritation may take several days to build up. This is why you sometimes get a delayed reaction.

A serious consequence of rotator cuff problems is the tightening of the joint capsule. This is called “adhesive capsulitis” or “frozen shoulder”. This is the opposite of instability. The capsule also has to be elastic to allow normal movement. The inner part of the capsule also secretes fluid to lubricate the joint. But if you have an irritation in the joint capsule, it can begin to stiffen. The normal fluid begins to get “sticky”. The capsule begins to lose its elasticity. You begin to lose motion. Since it hurts to move, you tend to hold the arm still. This allows the joint to stiff at a quicker rate. The longer this continues, the more trouble you have restoring normal use of the shoulder. These people may eventually have no more pain or irritation, but are unable to lift overheard due to tightness. With this is mind, use the following guidelines;

PREVENTING SHOULDER INJURIES

Avoid excessive overhead activities
If you have increased work at home using the shoulder (i.e. painting, yard work, lifting, scrubbing the floor, etc.)
Try to spread the work out over a few days
Avoid excessive reaching (use ladders or other ways to get as close as possible to your work)
If you are beginning a shoulder sport like golf, aerobics, swimming etc.
Stay safe in the off season
Increase rest in between activities (avoid consecutive days)
Alternate underhand with overhead activities (do more sidestroke in swimming, cut down on overheard serves)
Start out very conservatively with the amount of weight, amount of repetitions, or duration
If you are beginning a weight program:
Start with minimal overheard lifting
Start at a conservative weight
Wait 1-2 weeks before you try a more “stressful weight”
Obtain exercise advice from a knowledgeable source- you want to work the muscles in the back of the shoulder
Include rotator cuff strengthening exercised
If you think of starting aerobics with arm weights (or running with “heavy hands”)
Make sure you are completely with the sport without weights for at least one month
Start out with minimal weight for a small amount of time on alternative workouts
Obtain a good warm-up and stretching program to do before shoulder activity

IF YOU HAVE SHOULDER PAIN
REST!
Ice (a large food storage bag filled with ice and water will drape over shoulders) for 10-15 minutes, 2 or more times per week
Keep arm flexible by doing stretching exercises
If pain persists, or if you feel you are losing motion, seek professional help