Subacromial impingement
Updates to Article Attributes
Subacromial impingement is by far the most popularcommon form of shoulder impingement, and occurs secondary to attrition between the coracoacromial arch and the supraspinatus tendon or subacromial bursa.
Causes include:
Pathology
Aetiology
- os acromiale
- type III acromion
- acromioclavicular degenerative disease
- thickening of the coracoacromial ligament
- coracoacromial ligament ossification
- shoulder instability
- post traumatic deformity
- supraspinatus over development
- low lying acromion
Radiographic features
Although popularcommon, clinical diagnosis of subacromial impingement is difficult to demonstrate at imaging.
Static imaging modalities such as MRI and radiographs occasionally depict reduced subacromial distance as an indirect evidence to support clinical diagnosis.
Dynamic ultrasound may provide more reliable evidence by demonstrating abnormal contact between the coracoacromial arch and peritendinous tissue during shoulder abduction. However
However, dynamic diagnosis at US is not free of controversy: although earlier studies have demonstrated thickening of the subacromial bursa following shoulder abduction in symptomatic shoulders,1-3 a more recent investigation found no significant difference in the degree of bursal gathering in impingement patients compared with healthy volunteers.4
Anecdotal experience also suggests that slight contact between the coracoacromial arch and the subacromial bursa can occur in healthy individuals.5 Yet, significant contact or snapping between these two structures are not common in the absence of symptoms and suggest clinically relevant impingement.5
Related pathology
Less common types of shoulder impingement include:
-
subcoracoid impingement: affects
- which affectssubscapularis -
posterosuperior impingement: involves
- which involvesinfraspinatus
-<p><strong>Subacromial impingement</strong> is by far the most popular form of shoulder impingement, and occurs secondary to attrition between the coracoacromial arch and the supraspinatus tendon or subacromial bursa.</p><p>Causes include:</p><ul>- +<p><strong>Subacromial impingement</strong> is by far the most common form of shoulder impingement, and occurs secondary to attrition between the coracoacromial arch and the supraspinatus tendon or subacromial bursa.</p><h4>Pathology</h4><h5>Aetiology</h5><ul>
-<a href="/articles/supraspinatus">supraspinatus</a> over development</li>- +<a href="/articles/supraspinatus-muscle-and-tendon">supraspinatus</a> over development</li>
-</ul><p>Although popular, clinical diagnosis of subacromial impingement is difficult to demonstrate at imaging. Static imaging modalities such as MRI and radiographs occasionally depict reduced subacromial distance as an indirect evidence to support clinical diagnosis. Dynamic ultrasound may provide more reliable evidence by demonstrating abnormal contact between the coracoacromial arch and peritendinous tissue during shoulder abduction. However, dynamic diagnosis at US is not free of controversy: although earlier studies have demonstrated thickening of the subacromial bursa following shoulder abduction in symptomatic shoulders,<sup>1-3</sup> a more recent investigation found no significant difference in the degree of bursal gathering in impingement patients compared with healthy volunteers.<sup>4</sup> Anecdotal experience also suggests that slight contact between the coracoacromial arch and the subacromial bursa can occur in healthy individuals.<sup>5</sup> Yet, significant contact or snapping between these two structures are not common in the absence of symptoms and suggest clinically relevant impingement.<sup>5</sup> </p><p>Less common types of shoulder impingement include:</p><ul>- +</ul><h4>Radiographic features</h4><p>Although common, clinical diagnosis of subacromial impingement is difficult to demonstrate at imaging.</p><p>Static imaging modalities such as MRI and radiographs occasionally depict reduced subacromial distance as an indirect evidence to support clinical diagnosis.</p><p>Dynamic ultrasound may provide more reliable evidence by demonstrating abnormal contact between the coracoacromial arch and peritendinous tissue during shoulder abduction. </p><p>However, dynamic diagnosis at US is not free of controversy: although earlier studies have demonstrated thickening of the subacromial bursa following shoulder abduction in symptomatic shoulders,<sup>1-3</sup> a more recent investigation found no significant difference in the degree of bursal gathering in impingement patients compared with healthy volunteers.<sup>4</sup></p><p>Anecdotal experience also suggests that slight contact between the coracoacromial arch and the subacromial bursa can occur in healthy individuals.<sup>5</sup> Yet, significant contact or snapping between these two structures are not common in the absence of symptoms and suggest clinically relevant impingement.<sup>5</sup> </p><h4>Related pathology</h4><p>Less common types of shoulder impingement include:</p><ul>
-<a href="/articles/subcoracoid-impingement">subcoracoid impingement</a> - which affects <a href="/articles/subscapularis">subscapularis</a>- +<a href="/articles/subcoracoid-impingement">subcoracoid impingement</a>: affects <a href="/articles/subscapularis">subscapularis</a>
-<a href="/articles/posterosuperior-impingement-of-the-shoulder">posterosuperior impingement</a> - which involves <a href="/articles/infraspinatus">infraspinatus</a>- +<a href="/articles/posterosuperior-impingement-of-the-shoulder">posterosuperior impingement</a>: involves <a href="/articles/infraspinatus">infraspinatus</a>
Image ( destroy )
Image 1 X-ray (Scapular Y) ( update )
Image 3 MRI (PD fat sat) ( update )
