Last Updated: Monday, February 4, 2013
Evaluation of the Stiff Shoulder
The normal shoulder is the most moveable joint in the body. It enables us to put our hand in a wide range of positions for example reaching over head reaching cross the body reaching up the back and rotating out to the side. These motions are accomplished by motion between the humerus (arm bone) and scapula (shoulder blade) as well as between the scapula and the chest wall. These motions are called humeroscapular and scapulothoracic motions.
Average shoulder motions
Forward flexion: 170 degrees
External rotation: 80 degrees
Internal rotation: T5 segment
Cross body: 14 cm
Most of the common causes of shoulder stiffness are related to problems between the humerus and scapula.
The normally supple capsule around the joint can become stiff--a condition known as frozen shoulder. Frozen shoulders can come on after a period of disuse of the arm. A frozen shoulder can also come on for no apparent reason at all. Frozen shoulders can be particularly severe in individuals with diabetes.
Shoulder stiffness can also result when the normal gliding surfaces of the shoulder become scarred after injury or surgery--a condition known as post-traumatic stiff shoulder.
The shoulder can become stiff because the joint surfaces have lost their normal smoothness--as in arthritis.
Finally shoulder motion can be restricted by limited scapulothoracic motion (motion between the shoulder blade and the chest wall). Scapulothoracic range of motion can be limited by such factors as sternoclavicular arthritis acromioclavicular arthritis contracture rib or scapular fracture post-traumatic scarring tumor dislocation or other factors disrupting the scapulothoracic motion interface.
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About the Mechanics of Shoulder Stability: The capsule
In evaluating stiff shoulders it is essential to establish the circumstances surrounding the onset of stiffness the duration of the condition any tendency toward worsening or improvement and the possible existence of risk factors such as a period of immobilization metabolic disease (such as diabetes) or referred pain from the neck chest or abdomen.
The importance of the history
In post-traumatic stiff shoulders the relationship of loss of motion to previous surgery or injury becomes evident from the history.
The age of patients with idiopathic frozen shoulders presenting to our service is typically between 43 and 63 years.
Patients with frozen shoulders may have substantial functional losses. Patients with frozen shoulders had greatest difficulty sleeping comfortably on the affected side putting their hands behind their heads with the elbow out to the side lifting 8 pounds to the level of the top of their head without bending their elbow and throwing overhand.
Steps in examination
First obtain a quick assessment of the overall shoulder motion by examining the maximal ranges of elevation external rotation internal rotation and cross body adduction.
Then proceed to determine the humeroscapular range by stabilizing the scapula with one hand and putting the humerus through a passive range of motion with the other. The patient should remain relaxed during this examination to assure that muscle contraction is not limiting motion. Specific ranges of humeroscapular elevation and rotation can be measured by determining the positions that the humerus can attain in relation to the four palpable scapular reference points. Humeroscapular elevation of less than 90 degrees indicates stiffness especially if it is less than the contralateral normal shoulder.
Localized areas of capsular tightness or adhesions are identified by the pattern of motion restriction. For example a shoulder with limited humeral elevation in anterior scapular planes limited cross body adduction and limited internal rotation is likely to have tightness of the posterior capsule. A post-operative shoulder with isolated limitation of external rotation with the arm at the side is likely to have some combination of the following problems: scarring at the humeroscapular motion interface between the coracoid muscles and the subscapularis excessive tightness of the subscapularis and anterior capsule or contracture of the rotator interval capsule. Finally a shoulder with limited elevation after a previous acromioplasty is likely to have scarring at the humeroscapular motion interface between the acromion deltoid and rotator cuff.
The definition of a frozen shoulder requires a normal joint space and normal joint relationships.
Order certain views
Thus in the evaluation of a shoulder with restricted humeroscapular motion an axillary view and an anteroposterior radiograph in the plane of the scapula should be ordered to exclude the presence of narrowing of the radiographic joint space glenohumeral dislocation or joint surface fracture. When scapulothoracic range is limited a tangential (lateral) radiographic view of the scapula and a chest film are included to seek displaced fractures of the ribs or scapula scapulothoracic dislocation or osteochondroma on the anterior aspect of the scapula.