Subacromial Bursa

Description

• 
  Bursa aorund the shoulder joint: 1. subacromial-subdeltoid bursa 2. Subscapularis bursa 3. Sucoracoid bursa 4. Coracoclavicular bursa 5. Supra-acromial bursa.
• 
  Illustration of the subacromial bursa

(A) a healthy subacromial bursa and (B) an irritated bursa suggestive of subacromial impingement

Fluid-filled distension of the bursa with partial tearing of the supraspinatus tendon at its insertion (arrow)

Acute subacromial-subdeltoid bursitis: fluid distending the bursa more than 1.5 mm. The tendon fibers are poorly characterized due to anisotropy.

Name

• Subacromial Bursa
• Subacromial-subdeltoid bursa (SASD)
• Bursa Subacromialis
• Subdeltoid Bursa

General

• Bursa within the shoulder which protects the space between the acromion and rotator cuff
• In most health shoulders, it is simply a potential space
• Largest of the bursa within the glenohumeral joint
• One of the Bursa of the Shoulder

Gross Anatomy

• Found deep to the deltoid muscle and coracoacromial ligament
• Superior to the glenohumeral joint capsule, supraspinatus tendon
• It does not typically communicate with the glenohumeral joint
  • Communication can occur in the presence of rotator cuff pathology
• Laterally, it lies deep to the deltoid muscle, and this portion is often called subdeltoid bursa
  • Terminates an average of 4 cm from the mid-point of the acromion
  • Osseous landmark corresponds to posterior bursal reflection
• Medially, it is found in close relation to the acromioclavicular joint
• Envelopes the bicipital groove as it extends inferiorly
• Superficial relationships include the rotator interval, supraspinatus tendon
  • Invested by parallel layers of the peri-bursal fat
  • May or may not interface with infraspinatus

Function

• Prevents friction
• Protects the joint capsule
• Prevents wear and tear of the supraspinatus tendon

Ultrasound Findings

• Anechoic fluid can be seen within the subacromial bursa when inflamed
  • Physiological distention is typically less than 1 mm
• The hyperechoic per-bursal fat forms a prominent interface
  • Between the deltoid/acromion and the underlying supraspinatus
  • Allows for identification of the potential space
• Dynamic visualization
  • Abduction and adduction of the shoulder should demonstrate smooth translocation of the bursal reflection

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Clinical Significance

• Subacromial Impingement
• Subacromial Bursitis
• Septic Bursitis
• Rheumatoid Arthritis
• Rotator Cuff Tear

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See Also

• Physical Exam Shoulder
• Shoulder Anatomy (Main)
• Shoulder Pain (Main)
• Bursae Anatomy Main

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