The shoulder joint relies on the rotator cuff muscles and their tendons for stability and movement. Among these, the supraspinatus tendon plays a significant role in shoulder function. This article explores its location, characteristics, and how to palpate it.
Understanding the Supraspinatus Tendon
The supraspinatus is one of four muscles that comprise the rotator cuff. It originates from the supraspinous fossa, a shallow depression on the back of the shoulder blade (scapula), located above the scapular spine. From there, its tendon extends laterally, passing underneath the acromion process—a bony projection of the scapula—and over the head of the upper arm bone (humerus). The tendon then inserts onto the superior facet of the greater tubercle of the humerus.
This muscle’s primary function involves initiating the first 0 to 15 degrees of arm abduction. It also works in conjunction with the deltoid muscle to assist with abduction beyond this initial range, up to 90 degrees. Beyond its role in movement, the supraspinatus is also important for stabilizing the humeral head within the glenoid cavity of the scapula. Due to its path beneath the acromion, the supraspinatus tendon is susceptible to impingement, making it a frequently affected component of the rotator cuff.
Why Palpate the Supraspinatus Tendon?
Palpating the supraspinatus tendon helps identify areas of localized tenderness, which might suggest irritation or inflammation. It also allows for feeling variations in tissue texture, such as tightness or slight swelling, providing information about the tendon’s state.
This physical exploration can help pinpoint potential sources of discomfort or pain within the shoulder region. It is important to understand that these observations are for informational purposes only and do not constitute a diagnosis of any medical condition.
Preparation for Palpation
Preparation ensures comfort and accurate identification of anatomical features. The individual whose shoulder is being examined should be seated comfortably, with their shoulder and arm in a relaxed position. Adequate lighting is also beneficial to clearly visualize the bony landmarks of the shoulder.
A clear understanding of the relevant anatomical landmarks is necessary before starting. This includes locating the spine of the scapula and the acromion. Approaching the palpation with a gentle touch in a relaxed environment helps ensure both comfort and the ability to discern subtle tissue characteristics.
Step-by-Step Palpation Method
Begin by having the individual sit with their arm relaxed at their side. Locate the spine of the scapula, which is a prominent bony ridge on the back of the shoulder blade. Follow this spine laterally until it broadens into the acromion, the highest point of the shoulder.
Once the acromion is identified, slide your fingers just superior and slightly medial to its posterior edge, moving into the supraspinous fossa. This area is where the supraspinatus muscle belly resides, deep to the trapezius muscle. You may need to gently push through the trapezius fibers to access the deeper structures.
To locate the tendon more precisely, ask the individual to gently initiate a small abduction movement of the arm, lifting it slightly away from the body. This minimal movement helps engage the supraspinatus muscle and tendon, making it easier to feel its contraction or the rope-like structure of the tendon as it passes under the acromion. An alternative method involves placing the individual’s hand in the small of their back, which can draw the humeral head forward, potentially making the supraspinatus tendon more accessible for palpation around the greater tubercle. When palpating the tendon as it inserts onto the greater tubercle, you can initially locate the flat acromion process and then slide your fingers laterally off this area.
Applying light, consistent pressure with the pads of your fingertips is beneficial. The goal is to feel for the distinct, firm, cord-like texture of the tendon. If the arm is in a neutral position, the tendon can be deep to the acromion and less accessible. Subtle internal rotation of the shoulder can also help facilitate palpation of the supraspinatus insertion on the greater tuberosity.
Interpreting Findings and Important Considerations
When palpating, a normal supraspinatus tendon typically feels firm and cord-like. Any deviations from this, such as localized tenderness, warmth, swelling, or a soft, boggy, or thickened texture, are observations. Crepitus, a crackling or grinding sensation, can also be noted during movement. These findings do not diagnose specific conditions.
It is important to use gentle pressure throughout the palpation process. If the individual experiences increased pain, the palpation should be stopped immediately. This information serves an educational purpose and is not a substitute for professional medical advice. For any persistent pain, discomfort, or concerns regarding shoulder health, consulting a healthcare professional is necessary for an accurate diagnosis and appropriate treatment plan.