Subscapularis Muscle
Anatomy and Function
- The subscapularis is innervated by both the upper and lower subscapular nerves.
- Primary actions: internal rotation and adduction of the shoulder.
Fatty Infiltration as an Indicator
- Fatty infiltration of the subscapularis muscle is a specific but insensitive marker for subscapularis tendon tears.
- The variability of this finding relates to the chronicity of the tear.
- Fatty infiltration typically affects the superior portion of the subscapularis, sparing the inferior parts.
- This pattern is linked to the initiation of subscapularis tendon tears, which often start superiorly.
Clinical Implications
- Higher grades of muscular atrophy and fatty infiltration predict poorer functional outcomes and increased post-operative re-tear rates.
- These are independent predictors of surgical success.
#Subscapularis, #ShoulderMRI, #FattyInfiltration, #TendonTears, #RotatorCuff, #ShoulderAnatomy, #MuscleAtrophy, #OrthopedicSurgery, #ShoulderRadiology, #MuscleDegeneration
Clin N Am. 2020 May; 28(2):165-179
Skeletal Radiol. 2011 Mar; 40(3):255-69
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