Question: I have a client with pain near the rotator cuff. What is the best way to determine if it involves the supraspinatus or subscapularis? 

This is an excellent question because knowing which tissue needs addressing will improve treatment success, and shoulder injuries can be particularly confusing because so many tissues could be involved.

Anatomy Review: Rotator Cuff Muscles

The rotator cuff comprises four muscles: supraspinatus, infraspinatus, teres minor and subscapularis. These muscles are regularly implicated in shoulder complaints. However, it is common for someone to get a diagnosis of a rotator cuff tear or dysfunction without specification as to which rotator cuff muscle(s) is/are involved.

The supraspinatus and subscapularis are frequently involved in shoulder complaints. Because of their proximity and coordinated function, unraveling the role either play in a client’s shoulder complaint may be difficult.

Shoulder Symptoms Supraspinatus and Subscapularis May Share

One of the challenges with the supraspinatus and subscapularis muscles is they often share similar signs and symptoms for certain shoulder pathologies. A short list of what may occur when either muscle (or possibly both) is affected:

•  Anterior/lateral shoulder pain

•  Pain with active or passive flexion

•  History of repetitive overuse

•  Pain with resisted abduction or resisted flexion

•  Pain with active or passive shoulder abduction

The architecture of the subacromial region is a primary factor in injuries with both of these muscles.

Both muscles course under a region called the coracoacromial arch. This arch is comprised of the acromion process, coracoid process, and the coracoacromial ligament that spans between them (Figure 1).

Various shoulder motions may cause the supraspinatus or subscapularis to get pinched or compressed against adjacent structures under the coracoacromial arch.

Applying Your Knowledge: Getting to the Root Cause of the Shoulder Complaint

There are a few important evaluation procedures that can help you distinguish between supraspinatus and subscapularis involvement in certain shoulder complaints. Applying your knowledge of anatomy and shoulder mechanics will go a long way to help you make some of these distinctions.

One of the first places to begin is with palpation. While these muscles are close together, there are regions where they are distinctly separate, and palpating each of them may help identify if pain is reproduced from either muscle specifically.

Unfortunately, a good bit of the supraspinatus is inaccessible under the acromion process, and much of the subscapularis is inaccessible on the anterior face of the scapula. However, using palpation in combination with other evaluation procedures can create a more complete picture of the muscle’s potential involvement.

See Also: Understanding Ankle Mechanics and How Massage Therapists Can Better Help Clients in Pain

Additional Assessment: Subscapularis

Resisted medial rotation: Medial rotation is the primary action of the subscapularis when engaged in a concentric contraction. Resisting medial rotation recruits the muscle-tendon unit, and engaging this contraction is likely to reproduce the client’s primary pain if there is injury or damage to that muscle-tendon unit.

The supraspinatus is not significantly engaged during the resisted medial rotation. If this action reproduces pain, subscapularis involvement is more likely a part of your client’s shoulder complaint.

Passive lateral rotation: The subscapularis is stretched during passive lateral rotation and there is minimal load on the supraspinatus. So again, if this action reproduces pain, subscapularis involvement and not supraspinatus is the more likely answer.

Both of the above evaluation procedures may be made more accurate if the distal portion of the subscapularis tendon is palpated during the manual resistive test or passive stretch.

Additional Assessment: Supraspinatus

Resisted abduction: A primary action of the supraspinatus is to engage the early stages of shoulder abduction. Resisting abduction primarily recruits the supraspinatus and does not recruit much activity in the subscapularis, so if this motion increases pain, there is a greater likelihood of supraspinatus involvement compared to the subscapularis.

Manual resistive test: This variation on the resisted abduction may also help isolate supraspinatus activity. The manual resistive test is usually performed with the arm at about 45 degrees of abduction. Another method is to put a more significant load on the supraspinatus by bringing the arm into about 90 degrees of abduction and instructing the client to hold that position.

Downward pressure can then be applied to the distal upper extremity to evaluate if this action reproduces the client’s pain. If it does, there is a reasonable likelihood of supraspinatus involvement.

This position is the same used in the special orthopedic test called the drop arm test. Palpating the distal supraspinatus tendonduring this procedure (or during resisted abduction) can also increase the sensitivity.

Unlike the subscapularis, the supraspinatus is not easy to stretch in isolation. Consequently, stretching procedures during evaluation are not as effective when trying to isolate supraspinatus involvement.

Keep in mind no evaluation procedure can guarantee that any specific tissue is involved.

These evaluation procedures focus on muscle-tendon pathologies where there is a biological or biomechanical dysfunction in the muscle, like muscle strain and compression pathology, for example. There are other causes of pain complaints where additional factors play a primary role in the conditions, factors that are not identified through the evaluation procedures discussed here.

Using these physical examination procedures, however, can be very beneficial in narrowing down potential soft-tissue causes.

Specific and targeted treatment to each of these muscles will produce the best treatment results, and so being able to identify when these muscles are involved will help you achieve good outcomes with your client.

In addition, home care and movement rehabilitation suggestions will be more effective if you know which tissues to target. Massage therapists should keep in mind that other soft tissues in this region may be involved in the complaint, so a more detailed assessment may be required.

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