The subscapular and subcoracoid bursae: descriptive and functional anatomy

Area of Science:

• Anatomy
• Biomechanics

Background:

• The subscapularis muscle and associated bursae are vital for shoulder joint function.
• Understanding their intricate anatomical relationships is key to diagnosing and treating shoulder pathologies.

Purpose of the Study:

• To investigate the detailed anatomical structure and attachments of the subscapularis and subcoracoid bursae.
• To elucidate the relationship between these bursae and the subscapularis muscle in cadaveric shoulders.

Main Methods:

• Dissection of 42 fresh cadaveric shoulder specimens.
• Detailed examination of the subscapularis muscle, subscapularis bursa, and subcoracoid bursa.
• Documentation of fibrous attachments, connective links, and bursal fusions.

Main Results:

• Identified distinct fibrous bands within the subscapularis muscle, with the superior distal band being consistently thicker.
• Observed strong fibrous attachments of the subscapularis muscle to the scapula, particularly along the bony crests of the subscapular fossa.
• The subscapularis bursa was consistently found, often fused with the subcoracoid bursa in 28% of specimens, and featured fibrous arcs facilitating its movement with the muscle.

Conclusions:

• The subscapularis and subcoracoid bursae, through their strong fibrous attachments and unique structural adaptations, play a critical role in managing friction during glenohumeral joint movement.
• These bursae facilitate the subscapularis muscle's ability to adapt to significant changes in orientation, particularly around the coracoid process, ensuring smooth articulation.