Shoulder Health: An Overview of Anatomy and Injury

The Shoulder
Any discussion of shoulder health must first recognize that the shoulder is an extremely complex joint. By design, the shoulder is the most mobile and least stable joint in the body and very small changes can alter the mechanical function and can cause problems.

The muscles that stabilize and support the joint are primarily the rotator cuff muscles and the scapular stabilizers, the rhomboids, traps and serratus—what’s commonly called the shoulder girdle. It’s really more like a yoke that includes the clavicles that attach at the sternum, the glenohumeral joint (the ball-and-socket shoulder joint,) and the scapulae (the shoulder blades.)

The Rotator Cuff
The introduction to shoulder health for most gym trainees consists of instructions to do internal and external tubing exercises for the rotator cuff. Strengthening the rotator cuff muscles is often a good idea, but by no means is it a guarantee of optimal shoulder mechanics. You’ll never have proper shoulder mechanics with a weak rotator cuff—rotator cuff work is necessary, but it’s not sufficient.

Often you’ll see the rotator cuff referred to as tendons, but don’t rule out a rotator cuff muscle as the root cause of a problem. In fact, most of the damage that gets done by the bones fraying the tendon is originally because of a muscle problem.

How Rotator Cuff Structures Get Injured
The rotator cuff muscles get beat up for two reasons. First, they’re little muscles with a big job, and second, they’re in a position where the joint will literally grind them up if the shoulder isn’t functioning properly. This grinding is called impingement. If you hear a click or pop every time you hit a certain point in a movement, it might be impingement and you’re wise to address it. Over time that little abrasion can cause big trouble.

Strong rotator cuff muscles will be better able to do their jobs without getting injured from the strain and will help keep the shoulder moving properly. But strong external rotators alone do not insure healthy shoulder movement.

If you’re not flexible in the pectorals, you’re going to have trouble. And the muscles that control the scapulae have to be sufficiently strong—meaning the rhomboids, mid and lower traps and serratus.

Even if everything is strong and sufficiently loose, if your coordinating motor patterns aren’t sequencing well, you still might have trouble. Consider this: If your rotator cuff is injured, you may need to wait before you strengthen it. See a doctor; make sure there’s nothing torn that needs repair. You may get sent to a physical therapist if passive movement is in order.

How We Strengthen the Rotator Cuff
Regarding the rotator cuff, the current thinking in physical therapy involves several steps to get back to good function. The first involve healing the individual muscles, restoring strength and range of motion and getting them to neurologically fire well. That’s what those isolation exercises with tubing do (the ones we borrowed from physical therapy).

The next step is to relearn the motor patterns that cause these muscles work in concert with the whole body. Compound exercises are good, and exercises that make extra demands on stabilization may help a lot.

Ultimately, most people will have to do direct work to maintain adequate strength in the stabilizers. For one thing, if you aren’t doing elbows-out rows, you might not be hitting the rotator cuff much. Even if you are, there’s an excellent chance the big prime movers will get ahead of the stabilizers and wind up doing more than their share of the work, leaving the rotator cuff muscles lacking. The odds are small that rowing will strengthen all four of the rotator cuff muscles enough to adequately support the shoulder.

There are two ways to go: One is to periodically test the rotator cuff for strength, making sure adequate strength and range of motion are there in all the various positions. Then do exercises to bring up the weak points as necessary. The other is to just do some rotator cuff work. Since we’re talking about 10 minutes a week, just doing a bit of it is easy enough.

Rotator cuff strength is normally tested by seeing how much weight can be handled in direct rotator cuff exercises. Ideally, rather than look at that number in a vacuum, it would be compared to strength in compound upper-body exercises.

The rotator cuff external rotation exercises are just a small part of keeping a healthy shoulder. They are not the be-all answer you might expect as you see your gym mates grabbing the tubing to warm up before every training session.

shoulder anatomy, shoulder injury

Basic Shoulder Health
When looking at shoulders in terms of joint mobility and stability, we need to split up the idea of the shoulder girdle, because the scapula requires stability, while the glenohumeral joint requires mobility.

When there’s tightness in key areas, the shoulders give up stability to provide adequate movement in your hands, arms and thorax. Without stability in the shoulders, you’re on a sure path to injury. Until you’re flexible in a body segment away from the shoulder joints, your efforts to stay sound and get strong will only get you so far. To help assure basic shoulder function, stretch the wrists, pecs, lats and subscapularis until you have at least adequate flexibility, and plan on doing a few basic stretches for life.

Strengthen the rotator cuff and the muscles that control the scapulae using a wide variety of exercises. If the exercises you’re using aren’t having the desired results, try others. Work as hard on upper back and shoulder stabilizer strength as you do on pecs and biceps.

Input from the Serratus
A winging scapula, that flaring of the shoulder blade that’s supposed to be flat against the back of the rib cage, is caused by a weak serratus, or a habitually lazy one. The serratus muscle pulls and rotates the shoulder blade downward, and when it isn’t working right, the edge of the shoulder blade drifts up and flares out. Regular work on the serratus is imperative.

There are many misconceptions among weight trainers about what works the serratus. For example, the pullover, which has long been considered part-serratus exercise, doesn’t work the serratus much, if at all. You can contract your serratus while doing pullovers, but that isn’t really the motion that works it. On the contrary, the basic movement that really develops the serratus is the overhead press, preferably standing.

benchpressBench pressing can contribute to a dysfunctional serratus. Normally when you push in the horizontal plane, the serratus and the pecs, delts and triceps work together. The shoulder girdle is extended forward along with the arm. When lying on a bench, things go awry. The shoulder blade is squashed against the bench under the combined weight of the body and the bar, and it can’t move freely. Additionally, the ‘goal’ of the bench is to lock out the arms, not to get the bar as high as possible, meaning the serratus isn’t used to extend the shoulder girdle.

To further illustrate this, the serratus is sometimes called the boxer’s muscle. It gets very well developed by boxing, which requires a natural, full extension of the arm and shoulder girdle in concert for maximum reach and power.

To get the serratus back in gear, an isolation exercise is often the first step. The best one is probably shrugs done on an incline bench or standing with the bar overhead. If you have a problem on one side, it makes sense to do it with two dumbbells or kettlebells, or one hand at a time.

Another good exercise is called the push-up plus, or scap push-up. This is like a regular push-up, but you push past the plank position so the top of your back goes as high as possible. Try a regular push-up and then try a push-up plus, and you’ll feel the difference between a press and a full extension of the shoulder. Get into a push-up position and, keeping your elbows locked, push the back of your shoulders up as high as possible for reps. It’s like a shrug; the only motion is in the shoulder girdle. This is an excellent introductory corrective exercise for scapular stability.

When your serratus is functional, the overhead press is probably adequate to keep it strong and healthy.

Shoulder Joint Stabilization
The stabilizer muscles for the shoulder joint are not designed to keep a barbell from wobbling. That is more a function of balance, kinesthetics and proprioception.

The stabilizers are the muscles that help hold the joint together. It bears restating, the glenohumeral shoulder joint is the most mobile, and the least stable joint in the body. The structure of the ball-and-socket joint isn’t what you might picture; it’s more like a golf ball resting on a tee. The connective tissue of the shoulder joint achieves stability with aid from the surrounding muscles.

When doing a bench press, the muscles of the rotator cuff must work very hard to hold the joint together as if to keep the golf ball on the tee . . . all while under duress.

A Big Cause of Shoulder Problems
The supraspinatus is often what takes the beating when shoulder function is off in any way. However, just doing an exercise for the supraspinatus  would be missing the point, and possibly exacerbating a tear. The cause of a shoulder problem could be any combination of:

Tight wrists
Tight pecs
Tight lats
Tight traps
Excessive kyphosis
Weak lower traps
Tight rhomboids
Weak serratus
Weak external rotators
Tight subscapularis
Tight scalenes

. . . or, simply doing exercises that put the joint in an impingement position. For example, upright rows basically chop and saw away at the tendon in the top position.

An unbalanced shoulder will be an unhealthy shoulder before long, and that will hold you back in any sport or endeavor.

Reducing Tightness
For the whole imbalance issue, stretching the pecs is fully half the answer. Tightness in the pecs will hold back your efforts to strengthen the upper back.

Foam rolling the upper back will help loosen up the thoracic spine.

Developing the muscles that extend the upper spine will help, too. Do a good amount of overhead work, and work hard on your horizontal rows. Not all types of rowing will help; you want to do it as a whole-back exercise, not a lat exercise. This doesn’t mean cheat your rows, quite the contrary. The best thing you can do is probably strict barbell rows. Pendlay-style rows, named after Olympic coach Glenn Pendlay, are especially good and emphasize the extension of the upper back.

The overhead position is going to be really rough on the joint if you don’t let the shoulder blade move forward as the serratus contracts, which creates some space for the tendon when as the arm rises. This is going to be bad if a lack of thoracic extension has you hunched forward. See how it all works together?

Movement Sequencing
Physical therapists refer to scapulohumeral rhythm, which is the coordinated movement of the shoulder blade and arm, an important part of healthy shoulder function. It helps ensure the joint space isn’t closed at certain points in the range of motion; that is, it prevents impingement.

In a natural athlete with no issues or problems, it’s something that just happens, nothing to think about. If an injury or imbalance has corrupted that pattern, or you’ve worked a movement that undoes that pattern, it’s going to take some re-learning to restore it.

Bench pressing is one of the things that really turns that pattern off, especially if you do a lot of benching and not much overhead work, or maybe push-ups or general athletics or even physical labor that keeps the pattern alive.

In bench pressing, your shoulder blades are squashed against a bench and they aren’t going to move much, whatever you do. You can bench more if you immobilize the shoulder blades, but the idea there isn’t to make your shoulder healthy, it’s to bench more.

As you can see, bench pressing is an example of how we take a powerful exercise too far, and over time it causes systemic problems in how we move. It’s hard to beat the image of immobile shoulder blades when benching.

The lesson is simple: Limit bench pressing. At the very least, offset the bench work with horizontal rows (basically the opposite of the bench), and overhead pressing.

Shoulder Impingement

Acromion Types
If you’ve had long-lasting problems on both sides, it’s pretty likely you have a sharper shape in your acromion, that bone in the shoulder joint. If this is true, it makes you more susceptible to the rubbing pain of impingement. We all have some impingement, but those with sharper shaped acromions have higher tendency toward pain or even tears from it, and these people should be attentive to avoid impingement-causing exercises.

Type 1 is the most open of acromion types; type 2 is slightly closed; type 3 is the most closed, what physical therapists call ‘beaked.’ The beaked acromion is a problem because the beak of the bone sort of saws at the rotator cuff tendon when the space in the joint is compromised. This is a potential problem for everyone, but it’s worse when the bone is longer and pointier than average.

shoulder impingement

If the shoulder is making a pop at the same spot in each rep of an exercise, it’s usually impingement—connective tissue is rubbing the wrong way, sliding over a bump of bone or some other abrasion on the connective tissue. The tendon is pulled tight as it slides over bone and makes a strumming sound as it goes over a corner or nub in the bone. The abrasion will wear away at the tendon and can cause injury over time.

This is not a good thing to work through. If it hurts, stop doing it. If it clicks, stop doing it. Get the shoulder looked at by a medical professional. There’s an excellent chance physical therapy alone will eliminate the impingement. If you can do it before the soft tissue is damaged, you may be none the worse for the wear.

When the internal rotators are tight or the external rotators are weak, the shoulder gets pulled into the impingement position. The internal rotators are the pectorals, the lats and the subscapularis—these usually need stretching. The external rotators, which generally need strengthening, are the infraspinatis, teres minor and the supraspinatis. Many times, just working hard on rows to the sternum will help ease an impingement. It can’t hurt to try just working your rows hard.

Some of the things that will open up the joint and keep the bone off the tendon:

  • stretching the pecs, lats and traps
  • strengthening the external rotators, lower traps and serratus
  • mobilizing the thoracic spine

Another complication leading to impingement is scapulae that don’t move properly in concert with the arms. Strengthening the serratus and lower traps provides a base for healthy movement, but we also need to learn to move the right way, which may take some doing if the bad habits are ingrained. Impingement happens when the bones are out of the proper positions during movement. That is what impingement is, soft tissue pinched between the bones. If the bones were moving well, they wouldn’t pinch the soft tissue.

The supraspinatus muscle passes through a little slot between the bones. If you have weakness, tightness or imbalances in the shoulder, the bones get pulled into a position where they ding the supraspinatus. That is impingement.

When the thoracic spine is not mobile—when it’s stiff and unable to extend—the shoulders again get pulled into a bad position. There are deep muscles in the upper back that extend the thoracic spine. Rolling on a foam roller is a good first step to get the area moving.

Impingement happens when the bones are out of their proper positions during movement.  In many cases the soft tissue damage is of the tendons at the insertion of the rotator cuff muscles.

What most people need to do to avoid impingement:
Strengthen what’s weak,
Stretch what’s tight,

Re-learn how to move the arm, and
Avoid hazards.

However, it’s important to get guidance from a medical professional because what feels tight may not be tightness, and stretching it could cause a new and greater problem.

When You Have a Shoulder Injury
A shoulder injury effects movement action from the top down. No body movement is normal when a shoulder injury is present, including walking or running.

There are many ways to injure your shoulders, even if you’re strong . . . maybe even especially if you’re strong.

It takes more than the four muscles of the rotator cuff to develop a strong and stable shoulder. You can’t simply conclude your rotator cuff is weak because your shoulder’s injured. Some rotator cuff problems may be inevitable, but many or perhaps most can be prevented. If you can correct your shoulder function to relieve an impingement, you can save yourself an awful lot of trouble.

Very few people with shoulder pain need surgery, and most people respond quickly to a good therapy plan. First things first—don’t do anything to make it worse! If it hurts, don’t do it.

Second thing second, have it looked at by a professional. An athletic trainer, physical therapist, doctor or chiropractor are the first people to see.

The consensus among good chiropractors and PTs who treat athletes is that common shoulder problems respond really well to conservative, therapeutic measures. And some of these clinicians are getting those results with very basic resting, stretching and strengthening treatments.

More from OTP on shoulder health, injuries, rehab and exercise:

Sue Falsone Shoulder Video

Sue Falsone: The Shoulder

shoulder pain, shoulder anatomy Eric Beard

Eric Beard: Anatomy of Shoulder Impingement

Continue reading:

Sue Falsone Interview: Shoulder Anatomy and Dealing with a Shoulder Injury

Greg Dea: Bulletproofing the Volleyball Shoulder

If you are interested in Sue’s work with athletes, you can learn more in her book, Bridging the Gap from Rehab to Performance.

Sue Falsone Bridging the Gap