Subscapularis Anatomy
- Origin and Structure: Multipennate muscle arising from the subscapular fossa, consisting of 4 to 6 tendon slips.
- Insertion: Primarily on the inferior facet of the lesser tuberosity, with variable attachment to the bicipital groove and greater tuberosity. The inferior third has a muscular attachment to the anterior humeral metaphysis via a thin membranous structure.
- Innervation: Upper and lower subscapular nerves.
- Function: Internally rotates and adducts the shoulder.
Imaging Approach
- Axial Images: Evaluate for tears of the subscapularis.
- Biceps Tendon: Assess for subluxation or displacement.
- T1-Weighted Imaging (T1WI): Check for fatty infiltration and muscle atrophy.
- Sagittal Oblique Images: Confirm the presence and extent of tears.
References
- Clin N Am. 2020 May; 28(2):165-179.
- Skeletal Radiol. 2011 Mar; 40(3):255-69.
#Subscapularis, #ShoulderMRI, #RotatorCuff, #MSKRadiology, #BicepsTendon, #FattyInfiltration, #ShoulderInjury, #TendonTear, #MuscleAnatomy, #RadiologyEducation
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