What is Neer Test?
Neer test is used for detecting the presence of shoulder impingement syndrome. It is also known as Neer’s test, Neer impingement test, painful arc maneuver.
What exactly is the Shoulder Impingement Syndrome?
Shoulder impingement syndrome is a painful condition. It is found in about 50% of the patients who come to the doctor with a complaint of shoulder problems.
Shoulder impingement occurs when there is an impingement of rotator cuff tendons (especially the supraspinatus tendon), long head of biceps tendon, or subacromial bursa by the undersurface of the acromion process. It causes pain and irritation.
In other words, the acromion pinches (impinges on) or rubs against these above-mentioned structures (rotator cuff tendons, especially the supraspinatus tendon, long head of biceps tendon, or subacromial bursa), causing pain and irritation.
Shoulder impingement also results from the structural narrowing of the subacromial space. Let’s understand this term “Structural Narrowing of the Subacromial Space.”
Structural Narrowing of the Subacromial Space
The subacromial space is a “tunnel” in the shoulder joint.
Upper Part of the Subacromial Space – The upper part of the subacromial space is formed by the inferior surface of the acromion, the acromioclavicular ligament, and coracoacromial ligament.
Lower Part of the Subacromial Space – The lower part of the subacromial space is formed by the superior surface of the humerus head.
What structures lie in the Subacromial Space?
The structures that lie in the subacromial space are as follows
- Rotator Cuff Tendons (supraspinatus, infraspinatus, subscapularis, and teres minor).
- The long head of biceps Tendons.
- Subacromial bursa.
Note – Supraspinatus and Long head of biceps tendons are more commonly involved.
Importance of Subacromial Space
The subacromial space is quite small as measured on the radiograph. It is used as an indicator for the superior humeral head subluxation because of rotator cuff abnormality.
In 175 asymptomatic shoulders, this distance was found to be between 9 and 10 mm. In comparison, a distance of less than 6mm is considered to be an indicator of rotator cuff disease.
Several factors can contribute to this abnormal narrowing of the subacromial space, hence resulting in shoulder impingement syndrome.
Factors (causes) that can contribute to Narrowing of the Subacromial Space (Shoulder Impingement Syndrome)
Rotator Cuff Injury
When your rotator cuff gets injured or irritated. It swells up in much the same way as your ankle does when it is injured or sprained.
However, your rotator cuff is surrounded by bone, and the swelling causes other issues to occur. The swelling decreases the space around the rotator-cuff hence leading to rubbing against the acromion.
Like a vicious cycle, this rubbing of rotator cuff tendons against the acromion results in further swelling, which further narrows the space below the acromion.
Bursa is a small, fluid-filled sac that can be found between tissues (skin, joints, bones, muscles, and tendons). Due to that fluid, the bursa can be used as a cushion between muscles, tendons, skin or joints, or muscle). This helps in reducing the friction and irritation between the tissues that move against each other.
When the bursa is not irritated, joints or bones move smoothly or pain-free. But when it becomes swollen or inflamed, the condition is known as bursitis. This is also known as “subacromial bursitis.”
So when the bursa becomes inflamed, the space between the acromion and humeral head becomes narrow. And the time when you move the shoulder, the bursa gets pinched between the bones (the acromion and the humeral head). Hence this is the impingement, i.e., Shoulder impingement syndrome. The most frequent or common cause of shoulder bursitis is overuse or injury.
As explained above the Shoulder impingement is often referred to as rotator cuff tendonitis and or shoulder bursitis.
Other Factors include
The factor that can lead to shoulder impingement syndrome can be divided into intrinsic and extrinsic factors.
Intrinsic Factor – Intrinsic factors directly impact the subacromial space. This includes changes in the vascularity of the rotator cuff, rotator cuff degeneration, bony or anatomic anomalies, rotator cuff tendonitis or shoulder bursitis, etc.
Extrinsic Factor – Extrinsic factors include:
- Motor control problems and muscle imbalances of the rotator cuff and para scapular muscles.
- Postural changes.
- Functional arc movement.
- Precipitating factors which include training errors.
Identification of particular one cause of Shoulder Impingement Syndrome
Because a variety of problems may be associated with the shoulder impingement syndrome, isolating a particular problem as a cause is difficult. However, the cause of shoulder impingement has multiple factors(causes), as explained above. All causes (factors) are important, and the main cause, in any case, depends upon the individual circumstance.
What Is the Role of the Neer Test in detecting Shoulder Impingement Syndrome?
Neer test was invented by an orthopedic surgeon Dr. Charles S Neer, II MD, in 1972 based on his observations when he performed shoulder surgeries. Dr. Neer noted that there was an extensive degeneration in the supraspinatus tendon. According to him, the anteroinferior one-third of the acromion is thought to be the causative factor in the mechanical wear of the rotator cuff through a process known as impingement.
Dr. Neer believes (consider or think) that the supraspinatus tendon and the long head of the biceps tendon or subacromial bursa are subjected to repeated compression as the arm is lifted in forward flexion. Dr. Neer named this “the functional arc of elevation of the arm”.
Arthokinematic movement determines that the forward flexion of the humerus results in concomitant internal rotation of the humeral head. This means when we do forward flexion of the humerus, internal rotation of the humeral head occurs automatically or simultaneously.
The Neer Impingement test involves forced forward flexion with internal rotation of the humerus to stimulate motion or movement in the functional arc. This provokes pain and discomfort in symptomatic patients.
By focusing on the anterior acromion as the main source of impingement, rather than the whole acromion. Dr. Neer assisted in the development of the method and strategy to the acromial decompression in the region of the anteroinferior acromion, thus preventing the excision (cutting) of the lateral acromion.
The overall result after acromial decompression or anterior acromioplasty results in an accelerated rehabilitation program.
How Do You Perform The Neer Impingement Test?
Position of the Patient – The patient is asked to be in a sitting position or stand next to the examiner.
Position of the Examiner – The examiner should stand on the side which is being tested.
- After that, with one hand, the examiner depresses the patient’s affected side scapula.
- And with the other hand, the examiner internally rotates the patient’s affected arm.
- After that, the examiner forcefully raises the patient’s arm through a full range of forward flexion (performs maximally forced forward flexion) until the patient reports pain as you can see in the diagram given below.
Positive Neer Test
When your arm is lifted or raised above and pushed to the limit, the subacromial space, the space inside your shoulder joint where (Rotator Cuff Tendons, The long head of biceps Tendons, Subacromial bursa) resides becomes smaller.
The Neer test is considered positive if you feel pain or reproduction of the symptoms (familiar shoulder pain) during maximal forward flexion of the shoulder. It means the pain is most likely caused due to impingement of the bursa or tendons by the undersurface (anteroinferior one-third) of the acromion in your shoulder.
Accuracy of The Test
According to Hegedus et al. 2012, the Neer test has a sensitivity of 72% and specificity of 60%.
Sensitivity means how accurately a test can diagnose the condition. This test has a sensitivity of 72%.
Specificity means how accurately a test excludes or rules out the condition. This test has a sensitivity of 60%
As the Neer test has good sensitivity (72%) in diagnosing the shoulder impingement syndrome. But it also has a drawback, Neer test just only reveals that you suffer from shoulder impingement syndrome. But it does not reveal what specific structure in your shoulder joint is being pinched (e.g. Rotator Cuff, biceps tendon, shoulder bursa).
Your doctor may order further radiological tests (MRI or CT scan) or may perform other physical examination tests to get a more clear picture of what specific structures in your shoulder are being pinched (e.g. Rotator Cuff, biceps tendon, shoulder bursa).
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