What is shoulder impingement?
There are two types of rotator cuff pain associated with shoulder impingement (friction between the rotator cuff and the shoulder blade): bursitis and tendinitis. The groups most at risk for bursitis and tendinitis are athletes, the middle-aged and people whose work requires them to use their arms over their heads and/or frequently lift things. Bursitis and tendinitis are not acute conditions; they involve damage done over a period of time. Without proper medical intervention and care, shoulder impingement can turn into a torn rotator cuff.
Anatomy of the shoulder
The shoulder is the body’s most widely mobile joint and an exceedingly complicated mechanism. It is composed of many joints, tendons and muscles, giving our arms a broad range of motion that allows us to accomplish many manual tasks, but also making the shoulder quite vulnerable to injury.
The shoulder is composed of the following:
- The humerus (the arm bone that begins at the shoulder and ends at the elbow, held in the socket of the shoulder blade by the rotator cuff)
- The rotator cuff (four muscles that bind the “ball-and-socket” joint where the humerus meets the shoulder blade)
- The scapula (a triangular bone making up the back part of the shoulder; also known as the shoulder blade)
- The clavicle (the bone that connects the scapula to the upper breastbone; also known as the collarbone)
- Bursae (lubrication sacs located between the humerus and the outward end of the shoulder blade, the function of which is to make the rotator cuff’s movement smooth)
Types of shoulder impingement
Shoulder impingement can be divided into two main types:
- Bursitis—Bursitis occurs when your shoulder’s bursae become irritated.
- Tendinitis—Tendinitis occurs when the tendons of the rotator cuff become irritated.
The progressive inflaming of the rotator cuff has been likened to the gradual fraying of a rope. The pain and tenderness associated with shoulder impingement will start out as mild. It will likely hurt when you are performing the activity that damaged the shoulder in the first place. As the condition gets worse, the pain will become more constant. Also, your range of motion may be limited, and you may experience a loss of strength. The following are common shoulder impingement symptoms:
- Loss of strength
- Restricted range of motion
The symptoms of shoulder impingement may be mistaken for the symptoms of other medical conditions such as a torn rotator cuff or separated shoulder. Make sure you consult a doctor to determine if you have shoulder impingement, and get the appropriate treatment.
Shoulder impingement tends to be the result of cumulative damage, but in rare cases it is the result of a minor acute injury that becomes severe. The following are causes of shoulder impingement:
- Repetitive stress—Athletes, particularly those who play sports involving a lot of overhead activity, such as baseball, tennis and swimming, are vulnerable to rotator cuff injuries. Also, people such as painters and construction workers, who frequently work with their arms over their heads and often lift heavy loads, are vulnerable to bursitis and tendinitis.
- A minor injury—A minor shoulder injury can put extra stress on the rotator cuff and cause shoulder impingement.