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Have you wondered why it takes so long for the pain around a joint to resolve?

Perhaps this article will shed some light onto the issue and confirm the importance of identifying the problem in a painful joint, taking the time to address the issues and then making the commitment to heal your body.  

This article will address the nature of a normal joint and what changes may take place in a joint irritated by trauma, overuse, immobilization or surgery. Since there are a variety of different types of joints in the body we will address specifically a synovial joint and for this article our example will be the shoulder.     

Synovial joints exist where two bones that connect are surrounded by a capsule lined by a membrane that produces synovial fluid, the natural lubricating fluid in our joints. The joint is also surrounded by ligaments, deep postural muscles, nerves and a blood supply. 

The shoulder joint is a complex joint between the head of the humerus and a saucer shaped dent on the shoulder blade called the glenoid fossa. The bones are held together by a capsule, lined by a synovial membrane, ligaments and deep postural muscles, otherwise known as the rotator cuff. The deep postural muscles are activated by information that they receive from mechanoreceptors, small pressure receptors, deep with in the capsule, tendons and ligaments. These muscles are used for movement but they also play a vital role is protecting the joint from the eternal pull of gravity on the shoulder towards the ground. Finally to add to the complete picture the joint is surrounded by an active nerve and vascular system.  With all of these structures maintained in perfect balance the humeral head slides, glides and rolls in harmony around an axis in the glenoid fossa. 

Joint injury damages the ground substance within the ligaments, muscles and tendons, known as collagen.  When this takes place the mechanoreceptors within the collagen are also damaged. There is an interruption of their message system around the joint and the previous harmonious balance is altered. The information received by the deep postural muscle fibers is no longer accurate and they are not required to fire as often or with as much force. With less information the muscles receive less input, do not fire as effectively, and begin to weaken, commonly known as atrophy. They no longer protect the joint from the forces of gravity and the joint succumbs to gravitational forces. The joint no longer moves around its original axis and as a result spins around a “non physiological axis”. Essentially it rattles around in its capsule and causes more collagen trauma which may result in locking, additional collagen trauma, pain and muscle guarding and spasm. The muscle guarding and spasm decreases the circulation in the muscle and reduces some of the vital metabolic processes which lead to a collection of waste produces. These irritate nerve endings leading to more pain and the cycle continues. 

The cycle of pain, muscle guarding and collagen trauma will continue until the joint receives appropriate feedback and reeducation. Once again it is vital to understand the cause of pain in your joint, make time to address the issues and spend time in the healing process. From a Physical Therapy stand point it is important to understand exactly which structures are involved in the pathology and then to provide the tissue with the appropriate type and dose of exercise. 

Written by, Anne Thomas and Gary Miller owners of Body In Balance Physical Therapy. Believers in an integrated three dimensional approach to healing of our bodies.