The shoulder is a complex and highly mobile joint, allowing for a wide range of arm movements. This mobility relies significantly on a group of muscles and their tendons known as the rotator cuff. Among these important components, the supraspinatus tendon plays a notable part in shoulder function.
Locating the Supraspinatus Tendon
The supraspinatus tendon originates from a concave depression on the posterior aspect of the scapula, or shoulder blade, called the supraspinous fossa. From this origin, the tendon extends laterally, traveling underneath the acromion, which is a bony projection forming the top of the shoulder blade.
After passing beneath the acromion, the supraspinatus tendon inserts onto the top of the humerus, the upper arm bone, specifically at an area known as the greater tubercle. This positioning makes it the most superior of the four rotator cuff tendons.
Role of the Supraspinatus Tendon
The supraspinatus tendon, along with its associated muscle, performs important actions in shoulder movement and stability. It is involved in the initiation of arm abduction, which is the motion of lifting the arm away from the body to the side. While it initiates this movement, the deltoid muscle takes over for further abduction beyond approximately 15 degrees.
Beyond initiating abduction, the supraspinatus also contributes to stabilizing the humeral head within the glenoid cavity, the shallow socket of the shoulder blade. It helps to keep the humerus centered in the joint, preventing it from slipping downward. This stabilization is important for smooth and controlled overhead movements.
Why the Supraspinatus Tendon is Vulnerable
The supraspinatus tendon is susceptible to injury due to several anatomical and functional factors. Its pathway through a narrow space, known as the subacromial space, beneath the acromion makes it prone to impingement. This means it can get pinched or compressed, especially during overhead arm movements.
Repetitive overhead activities, such as those found in certain sports or occupations, can lead to wear and tear on the tendon, increasing its vulnerability to injury. The supraspinatus tendon also has a relatively limited blood supply in certain areas, which can hinder its ability to heal after injury. Age-related degeneration can weaken the tendon over time, making it more susceptible to tears.
Recognizing and Addressing Supraspinatus Issues
Problems with the supraspinatus tendon often cause specific symptoms affecting daily activities. Individuals may experience pain, particularly when lifting the arm overhead or reaching. Pain can also occur at rest or during the night, especially when lying on the affected shoulder.
Other signs include weakness when attempting to lift the arm or perform overhead tasks, and a reduced range of motion in the shoulder. Some individuals might also notice clicking or popping sensations during shoulder movements. If these symptoms persist, worsen, or significantly impact daily life, consulting a healthcare professional is advisable. Initial self-care measures include rest, applying ice to the affected area, and avoiding activities that aggravate the pain.