Lower Back Issues

Impingement Syndrome

Causes
Usually, there is enough room between the acromion and the rotator cuff so that the tendons slide easily underneath the acromion as the arm is raised. But each time you raise your arm, there is a bit of rubbing or pinching on the tendons and the bursa. This rubbing or pinching action is called impingement.

Impingement occurs to some degree in everyone’s shoulder. Day-to-day activities that involve using the arm above shoulder level cause some impingement. Usually it doesn’t lead to any prolonged pain. But having poor posture, continuously working with the arms raised overhead, repeated throwing activities, or other repetitive actions of the shoulder can cause impingement to become a problem. Impingement becomes a problem when it causes irritation or damage to the rotator cuff tendons.

Raising the arm tends to force the humerus against the edge of the acromion. With overuse, this can cause irritation and swelling of the bursa. If any other condition decreases the amount of space between the acromion and the rotator cuff tendons, the impingement may get worse. For example, poor posture that involves an increased forward curve in the upper back (kyphosis) and rolling inward of the shoulders affects the alignment of the humerus under the acromion. This alters the biomechanics of the shoulder (the ability of the shoulder to move freely and effeciently in space) which means even daily activity such as reaching increases the contact under the acromion.

Bone spurs can reduce the space available for the bursa and tendons to move under the acromion. Bone spurs are bony points. They are commonly caused by wear and tear of the joint between the collarbone and the scapula, called the acromioclavicular (AC) joint. The AC joint is directly above the bursa and rotator cuff tendons.

In some people, the space is too small because the acromion oddly sized. In these people, the acromion tilts too far down, reducing the space between it and the rotator cuff.

Symptoms
Impingement syndrome causes generalized shoulder aches in the condition’s early stages. It also causes pain when raising the arm out to the side or in front of the body. Most patients complain that the pain makes it difficult for them to sleep, especially when they roll onto the affected shoulder.

A reliable sign of impingement syndrome is a sharp pain when you try to reach into your back pocket. Asthe condition worsens, the discomfort increases. The joint may become stiffer. Sometimes a catching sensation is felt when you lower your arm. Weakness and inability to raise the arm may indicate that the rotator cuff tendons are actually torn.