Shoulder Impingement (Bursitis, Tendinitis), Symptoms and Causes

There are two types of rotator-cuff pain associated with friction between the rotator cuff and the shoulder blade (a condition known as shoulder impingement): bursitis and tendinitis. The shoulder is an exceedingly complicated mechanism. It is composed of many joints, tendons and muscles. Its sophistication gives our arms a broad range of motion, which allows us to accomplish many manual and communicative tasks, but it also makes them quite vulnerable to injury.

Your upper arm bone (known as the humerus) is held in the socket of the shoulder blade (known as the scapula) by the rotator cuff, which is composed of four muscles that become tendon where they make contact with the joint capsule. The groups most at risk for bursitis and tendinitis are athletes, people who do work with their arms over their heads and/or frequently lift things, and the middle-aged. The reason for this is that 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, the human body’s most widely mobile joint, is composed of the following:

  • The scapula (a triangular bone making up the back part of the shoulder; also known as the shoulder blade)
  • The humerus (the arm bone that begins at the shoulder and ends at the elbow)
  • The clavicle (the bone that connects the scapula to the upper breastbone; also known as the collarbone)
  • The rotator cuff (muscles, of which there are four, that bind the “ball-and-socket” joint where the humerus meets the shoulder blade)
  • Bursa (a lubrication sac 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 bursa becomes irritated.
  • Tendinitis – Tendinitis occurs when the tendons of the rotator cuff become irritated. 

Causes of Shoulder Impingement
Shoulder impingement tends to be the result of accumulative damage, but in rare cases is the result of a minor acute injury that becomes severe. The following are the causes of shoulder impingement:

  • Repetitive stress – Athletes, particularly those who play sports that involve a lot of overhead activity, like baseball, tennis and swimming, are vulnerable to stressed rotator cuff injuries. Also, people who work with their arms frequently over their heads and often lift heavy loads, like painters and construction workers, 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.

Symptoms of Shoulder Impingement
The progressive inflaming of the rotator cuff has been likened to the progressive fraying of a rope. As with a rope, eventually you will reach a critical mass of wear, and something will have to be done about it. The pain and tenderness associated with shoulder impingement will start out mild. It will likely hurt when you are performing the activity that damaged the shoulder in the first place. As the condition gets worse, though, 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:

  • Pain
  • Swelling
  • Tenderness
  • Loss of strength
  • Restricted range of motion

The symptoms of shoulder impingement may be mistaken for the symptoms of other medical conditions (torn rotator cuff, separated shoulder, etc.). Make sure you consult a doctor in order to determine if you have shoulder impingement and get the appropriate treatment. 

The multidisciplinary team of orthopaedic experts at North Shore-LIJ Orthopaedic Institute in New York treats shoulder impingement as well as a broad range of conditions that affect the bones within the body.

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