Case Study - Shoulder Pain
Presentation
A 55 year old male is referred to your for evaluation. He explains that he has had pain in his left shoulder for the last year and that this pain has been progressively worse for the last 3 - 4 months. In reviewing your patient's history, you find that he is a high school science teacher, about 5'3" in height, and is in generally good health. He is not active in sports and reports no traumatic injuries to his shoulder. He states that the pain started to worsen over the winter. His roof leaked when it snowed and he had to constantly rake the snow off his roof. By pointing, he indicates that the pain is most noticeable at the top and side of his shoulder. The shoulder "hurts a little" at rest, but the pain becomes severe when he tries to move his left arm across his body or when he tries to raise the arm over his head.
Examination
1. The first step in your examination of the patient is to inspect both shoulders to see if:
- there is drooping on one side.
- the acromion is very visible on one side.
- the clavicle is overriding the acromion.
Explain what each of the above findings would indicate concerning the pathology of the shoulder.
2. Next, use the figure below to label the bony components of the shoulder girdle. Indicate which components are palpable.
3. You now examine the shoulder to obtain better information concerning the pain that your patient is experiencing. The area between the acromion and greater tubercle is very tender and painful. You ask the patient to perform the following movements of his shoulder:
- Flexion
- Extension
- Abduction
- Adduction
- Inward Rotation
- Outward Rotation
For each movement, provide the prime mover(s) and whether the patient found the movement painful. Would the pain be reproduced if these movements were performed passively?
4. You ask the patient to repeat the movement of shoulder abduction against mild resistance. Discuss the process of shoulder abduction.
The picture below shows the first phase of abduction. What is happening?
The following image shows Phase 2 of abduction. What is happening in this picture?
The following image shows Phase 3 of abduction. What is happening in this picture?
Your patient performs these movements as shown, and reports that while there is no pain at the start (Phase 1) or end (Phase 3) of abduction, there is significant pain abducting the arm to the horizontal (Phase 2).
5. Based on the findings of your physical exam, what is your diagnosis?
Discussion of diagnosis... its etiology and the anatomical basis of the symptoms produced:
Observe the figure below:
This figure (above) is a diagram of a normal shoulder. Below is a diagram that depicts shoulder impingement.
With shoulder impingement, the space between the acromion and the head of the humerus is narrowed so that the tendon of the supraspinatus muscle rubs against the underside of the acromion. This produces pain and can lead to a tearing of the tendon.
The most common causes of shoulder impingment are arthritis of the acromion ("hooking" of the acromion - see the x-ray image below) or weakness of the rotator cuff muscles.
The following image....
is an x-ray taken of your patient's affected shoulder. The radiograph is normal in appearance with no evidence of hooking or acromial arthritis.
The following figure is an MRI of a normal shoulder:
Notice that there is a defined space between the supraspinatus tendon and the acromion.
The image below is an MRI of your patient's shoulder:
Notice that the supraspinatus tendon is right against the acromion.
In the case of your patient, the shoulder impingement is not a result of any deformity of the acromion. The problem is a result of weakness of the rotator cuff muscles. Observe the figure below:
These rotator cuff muscles... the supraspinatus (1), infraspinatus (2), teres minor (3), and the subscapularis... are the main stabilizing muscles of the shoulder. These muscles help keep the head of the humerus applied tightly to the glenoid fossa through any range of shoulder movement. If these muscles weaken, as happened in the case of your patient, the movements of abduction and flexion result in the head of the humerus riding up to the glenoid cavity, causing the supraspinatus tendon to rub against the acromion.
The image below shows the importance of these muscles in movements of the shoulder:
In the figure above, the quarterback is set to throw a pass. His shoulder is in a position of abduction and external rotation. Abduction is a result of action of the deltoid muscle while the teres minor and infraspinatus muscles produce external rotation. If the rotator cuff muscles are not strong, this kind of motion will result in the supraspinatus tendon rubbing against the acromion. The resulting pain has shortened the career of many a baseball pitcher and football quarterback.
What is the best and most conservative treatment for this type of shoulder impingement?
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Last Modified: Wednesday, 30-Jul-2003 09:32:52 EDT