Rotator Cuff Muscles Mnemonic
The four rotator cuff muscles that stabilize the glenohumeral joint and rotate the humerus. These muscles form a "cuff" around the shoulder joint head and are commonly injured in falls and repetitive overhead activities.
The Mnemonic
"SITS"
Breakdown
Supraspinatus
Initiates abduction (first 15°), most commonly torn, runs under acromion
Infraspinatus
External rotation, posterior cuff, second most commonly torn
Teres minor
External rotation, works with infraspinatus, rarely torn alone
Subscapularis
Internal rotation, anterior cuff, largest rotator cuff muscle
Clinical Relevance
Supraspinatus tears cause painful arc syndrome and positive drop arm test. Impingement syndrome results from supraspinatus compression under acromion. MRI is gold standard for diagnosis.
Study Tips
- ✓Supraspinatus = Superior, initiates Abduction
- ✓Infraspinatus + Teres minor = External rotation (posterior muscles)
- ✓Subscapularis = Subscapular fossa, Internal rotation (anterior)
- ✓All insert on greater tubercle EXCEPT subscapularis (lesser tubercle)
FAQs
Common questions about this mnemonic
Supraspinatus runs through the narrow subacromial space. Repetitive overhead activities cause impingement between the acromion and humeral head, leading to tendinopathy and eventual tearing.
Patient holds arms at 90° abduction, 30° forward flexion, thumbs pointing down (like emptying a can). Examiner pushes down on arms. Weakness or pain indicates supraspinatus pathology.