Wednesday, January 14, 2015
Wisdom Wednesday: The Shoulder
Shoulder pain is a very common clinical complaint, second only to low back pain in frequency. Research indicates that most of us tear our rotator cuff (the group of muscles that support the shoulder joint) sometime in our lives and most of us actually forget the injury.
I guess I’m not like most people because I vividly remember tearing both my right and left rotator cuff even though the first injury was 45 years ago.
The shoulder joint is very complex. It is a little like the hip joint but is designed with much greater range of motion but can’t tolerate constant weight bearing. There are no ligaments in the joint proper. Ligaments attach bone-to-bone. So the head of the humerus (upper arm) is suspended from the glenoid fossa (shoulder socket) by a series of tendons attached to the rotator cuff muscles.
Think of the humerus as the gondola on a hot air balloon. As long as all the cables (tendons and muscles) are even in strength and tension, the balloon sits level. However, shorten or break even one of those cables and the gondola will lurch to one side. When the humerus is riding unevenly in the socket, inflammation and subsequent degeneration occur.
To complicate matters, when the shoulder is lifted above level, the clavicle (collar bone) and scapula (wing bone) both elevate to change the shape of the joint allowing even greater range of motion.
The four rotator cuff muscles are the supraspinatus, infraspinatus, teres minor, and subscapularis. Each one acts to strengthen and facilitate motion in the shoulder but all have their unique evaluation and treatment issues.
The supraspinatus is by far, the most important of the rotator cuff muscles. It is the only skeletal muscle that contracts constantly, even while you are sleeping. This constant contraction helps keep the arm properly seated in the socket. Weakness or a tear the in supraspinatus will result in frequent dislocation of the shoulder. This is usually the case with the patient that complaints that their shoulder gets worse or begins to hurt while sleeping. In AK (Applied Kinesiology), the supraspinatus is associated with the brain. Sometimes the supraspinatus will be weak because of a neurotransmitter imbalance or hormonal issue. For example, the herb chaste tree might strengthen a chronic weak supraspinatus by stimulating increased melatonin production from the pineal gland. This corrects the underlying weakness and the shoulder issue resolves.
The infraspinatus the second most important rotator cuff muscle. If it hurts to take your arm back to throw a ball, that’s generally an infraspinatus issue. Weakness or tearing of the infraspinatus will often significantly limit motion in the shoulder. Both the infraspinatus and teres minor relate to the thyroid. Hypothyroidism and Hashimoto’s thyroiditis often will create rotator cuff weakness.
Although the teres minor is associated with the thyroid, clinically I find subluxation of the mid-back is the most common cause of a weak teres minor.
The subscapularis often will test as weak because of pain rather than true weakness or a tear. It is associated with the heart. I have seen subscapularis weakness secondary to cardiac insufficiency.
Testing of the shoulder is really straight forward – measure the range of motion then test the rotator cuff muscles. Mechanical correction is also fairly easy. Frequently (about 50% of the time) manipulation of the shoulder, spine and/or the shoulder girdle will resolve all muscle weakness. When correcting the structural issues fails is when the real detective work starts.
Shoulder pain can also be referred. Cardiac issues (angina) commonly refers pain into the left shoulder. Gallbladder inflammation will often cause referred pain into the right shoulder. GERD (gastroesophogeal reflux disease) can refer pain into both shoulders, along with acute mid-back pain.
The Bottom Line:
Shoulder pain is fairly straight forward when it is a mechanical issue, more complex if there is underlying organ dysfunction or disease. If you have a shoulder problem, please have it evaluated by a physician that is proficient in AK.