Logan Steele
The supraspinatus is a muscle that is part of the rotator cuff, which is a group of four muscles that surround the shoulder joint. It is a small, triangular-shaped muscle that originates from the supraspinous fossa of the scapula and inserts into the upper facet of the greater tuberosity of the humerus. The supraspinatus muscle is responsible for abducting the arm at the shoulder joint and helping to stabilize the shoulder by resisting the downward pull of the upper limb. This muscle is often associated with shoulder injuries and pain, particularly in individuals who participate in sports involving sudden and forceful movements of the arm.
| Characteristics | Values |
|---|---|
| What is it? | One of the four muscles that make up the rotator cuff |
| Location | Deep to the trapezius muscle and superior to the spine of the scapula and infraspinatus muscle |
| Innervation | Suprascapular nerve |
| Function | Abduction of the arm, pulls the head of the humerus medially towards the glenoid cavity, resists inferior gravitational forces placed on the shoulder joint |
| Blood supply | Suprascapular artery, a branch of the thyrocervical trunk of the subclavian artery |
| Vein drainage | Subclavian vein |
| Tendons | Extends laterally, passing under the acromion process and over the head of the humerus |
| Common issues | Calcification of the tendon, tears, impingement |
| Tests | Empty Can Test, Full Can Test |
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What You'll Learn
- The supraspinatus muscle is the most important muscle of the rotator cuff
- It is the most frequently torn rotator cuff muscle
- The supraspinatus muscle is innervated by the suprascapular nerve
- Calcification of the supraspinatus tendon is a major contributor to shoulder pain
- The supraspinatus muscle abducts the arm at the shoulder joint
The supraspinatus muscle is the most important muscle of the rotator cuff
The supraspinatus muscle is indeed a muscle, and it is the most superiorly located of the four muscles that comprise the rotator cuff of the shoulder joint. It is a small, triangular-shaped muscle, situated deep to the trapezius muscle in the posterior scapular region. The supraspinatus is considered the most important muscle of the rotator cuff due to its role in providing joint stability and its involvement in various shoulder movements.
One of the primary functions of the supraspinatus muscle is to stabilize the shoulder joint by resisting the inferior gravitational forces acting on it due to the weight of the upper limb. It achieves this by firmly holding the head of the humerus against the glenoid fossa, preventing it from slipping inferiorly. This stabilization helps maintain the structural integrity of the joint and prevents injuries.
The supraspinatus muscle is also crucial for abduction of the arm, which is the movement of lifting the arm away from the body. It is responsible for the initial 10 to 15 degrees of abduction, after which the deltoid muscle takes over as the primary mover. Additionally, the supraspinatus assists the deltoid muscle in abducting the shoulder by compressing the humeral head and stabilizing it at the glenohumeral articulation. This coordination between the supraspinatus and deltoid muscles ensures smooth and efficient arm movements.
Furthermore, the supraspinatus muscle plays a significant role in maintaining balance among the other rotator cuff muscles. This balance contributes to the overall stability of the joint and helps prevent injuries. The supraspinatus is the most frequently torn muscle of the rotator cuff, making it susceptible to trauma and wear and tear from overuse or misuse.
The supraspinatus muscle receives its nerve supply from the suprascapular nerve, which arises from the superior trunk of the brachial plexus. It receives arterial blood from the suprascapular artery, a branch of the thyrocervical trunk of the subclavian artery. Understanding the anatomy and functions of the supraspinatus muscle is essential for diagnosing and treating shoulder injuries effectively.
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It is the most frequently torn rotator cuff muscle
The supraspinatus is indeed a muscle, and it is one of the four muscles that make up the rotator cuff. It is the most frequently torn muscle of the rotator cuff, and tears can be partial or full-thickness. The supraspinatus muscle is located deep to the trapezius muscle and superior to the spine of the scapula and infraspinatus muscle. It is responsible for abduction of the arm, and it assists in preventing the head of the humerus from slipping inferiorly.
There are several reasons why the supraspinatus muscle is the most frequently torn muscle in the rotator cuff. Firstly, it is the most important muscle of the rotator cuff, providing joint stability. This means that it is susceptible to trauma and wear and tear from overuse and misuse. For example, activities such as baseball, tennis, rowing, and weightlifting can put stress on the supraspinatus muscle due to the repetitive nature of the shoulder motions involved.
Additionally, age-related degeneration is a common cause of rotator cuff tears, and the supraspinatus muscle is no exception. As people age, the blood supply to the rotator cuff tendons decreases, impairing the body's ability to repair tendon damage. This makes older individuals more susceptible to tendon tears, with people over 40 at greater risk. Furthermore, bad posture is a leading risk factor for supraspinatus tears, and the dominant arm is typically more affected.
The supraspinatus muscle is also in direct contact with the bursa, a lubricating sac between the rotator cuff and the bone on top of the shoulder. When the rotator cuff tendons are injured or damaged, the bursa can become inflamed and painful, leading to further issues. Calcification of the supraspinatus tendon is also a major contributor to shoulder pain and can worsen following a supraspinatus tear.
Treatment options for a torn supraspinatus muscle include rest, icing the shoulder, non-steroidal anti-inflammatory drugs (NSAIDs), and physical therapy. In some cases, surgery may be recommended, especially for younger patients with full-thickness tears and a significant risk of irreparable rotator cuff changes.
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The supraspinatus muscle is innervated by the suprascapular nerve
The supraspinatus muscle is indeed a muscle. It is a small muscle in the upper back that runs from the supraspinous fossa superior portion of the scapula (shoulder blade) to the greater tubercle of the humerus. It is one of the four rotator cuff muscles and is the most important one. It is located deep to the trapezius muscle in the posterior scapular region.
The supraspinatus muscle performs abduction of the arm and pulls the head of the humerus medially towards the glenoid cavity. It works in cooperation with the deltoid muscle to perform abduction, especially when the arm is in an adducted position. The supraspinatus muscle also helps to stabilize the shoulder joint and resist the inferior gravitational forces placed on it due to the weight of the upper limb.
The supraspinatus muscle is susceptible to injury, which can cause pain and affect shoulder functionality. Calcification of the supraspinatus tendon is a common cause of shoulder pain and can be worsened by a supraspinatus tear. Arthroscopic surgery has been shown to be effective in treating full-thickness supraspinatus tears and improving shoulder functionality. Suprascapular nerve entrapment syndrome can also cause shoulder pain and muscular atrophy of the supraspinatus muscle. This can be due to nerve entrapment or compression within the suprascapular canal.
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Calcification of the supraspinatus tendon is a major contributor to shoulder pain
The supraspinatus is a muscle that is part of the rotator cuff. It is located deep to the trapezius muscle and superior to the spine of the scapula and infraspinatus muscle. The supraspinatus muscle abducts the arm at the shoulder by fixing the head of the humerus firmly against the glenoid fossa. It also helps to resist the inferior gravitational forces placed on the shoulder joint due to the downward pull of the upper limb.
Calcific tendinopathy (CT) of the shoulder is a common, painful condition caused by the presence of calcium deposits in the rotator cuff tendons. It usually results in shoulder pain and decreased range of motion. CT occurs more frequently in the supraspinatus tendon than in any other tendon. In fact, 63% of cases occur in the supraspinatus tendon, with 20% occurring in both the supraspinatus and subscapularis tendons.
The calcium deposits that characterise CT can become inflamed and cause pain. This pain can be sudden or intense with shoulder movement, and it may disrupt sleep. Other symptoms of CT include reduced range of motion, stiffness, and radiating pain up into the suboccipital region or down into the fingers. CT can be diagnosed using shoulder x-rays, which will reveal visible signs of calcium deposits overlying the rotator cuff insertion.
Treatment for CT typically consists of NSAIDs, physical therapy, corticosteroid injections, and ultrasound-guided needle lavage. In some cases, arthroscopic decompression of the calcium deposits may be necessary. Most cases of CT can be treated without surgery, and the condition can be resolved quickly. However, periodic checks by a healthcare provider are recommended, especially if the patient has had CT before.
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The supraspinatus muscle abducts the arm at the shoulder joint
The supraspinatus muscle is indeed a muscle, and it is one of the four muscles that make up the rotator cuff, along with the infraspinatus, teres minor, and subscapularis muscles. It is the smallest and most superiorly located of these four muscles, residing in the supraspinous fossa of the scapula, above the spine of the scapula. The supraspinatus muscle is innervated by the suprascapular nerve, which is formed by the anterior rami of spinal nerves C5 and C6. It receives arterial supply from the suprascapular artery, a branch of the thyrocervical trunk of the subclavian artery.
The supraspinatus muscle is responsible for abducting the arm at the shoulder joint. It works in cooperation with the deltoid muscle to perform abduction, especially when the arm is in an adducted position. During the first 10 to 15 degrees of abduction, the supraspinatus muscle is the main agonist, with the deltoid muscle becoming increasingly more effective at abducting the arm beyond this range. The supraspinatus muscle achieves abduction by fixing the head of the humerus firmly against the glenoid fossa, also known as the glenoid cavity. This action helps to stabilise the shoulder joint and resist the inferior gravitational forces placed on it due to the weight of the upper limb.
The supraspinatus muscle is susceptible to trauma and is the most frequently torn rotator cuff muscle, often as a result of sports involving sudden forceful movements of the upper limb. Calcification of the supraspinatus tendon is a major contributor to shoulder pain and can be worsened by a supraspinatus tear. Arthroscopic surgery has been shown to be effective in treating full-thickness supraspinatus tears and improving shoulder functionality.
The supraspinatus muscle also plays a role in resisting inferior displacement of the humeral head during abduction, allowing the deltoid muscle to abduct the humerus without causing impingement of the rotator cuff. This muscle is consistently recruited prior to movement of the limb, and it helps to maintain balance among the other rotator cuff muscles, providing stability to the joint.
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Frequently asked questions
The supraspinatus is a small, triangular-shaped muscle that is one of the four muscles that make up the rotator cuff. It is the most superiorly located of the rotator cuff muscles.
The supraspinatus muscle abducts the arm at the shoulder joint by fixing the head of the humerus firmly against the glenoid fossa. It also helps to stabilise the shoulder joint by resisting the inferior gravitational forces placed on the joint due to the downward pull from the weight of the upper limb.
The supraspinatus muscle is the most frequently torn rotator cuff muscle, often as a result of sports involving sudden forceful movements of the upper limb. A 2010 study found that patients who received early surgery for a full-thickness supraspinatus tear had superior function compared to those who had delayed surgery.
