Rotator Cuff Muscles

Description

Illustration of the rotator cuff muscles

MRI of the rotator cuff muscles as seen in sagittal plane

Name

• Rotator Cuff Muscles
• Rotator Cuff
• SITS Muscles (Supraspinatus, Infraspinatus, Teres minor, Subscapularis)
• Shoulder Rotator Cuff Muscles
• Glenohumeral Stabilizer Muscles
• Dynamic Stabilizers of the Shoulder
• Rotator Cuff Muscle Group

General

• Functional anatomic complex of 4 muscles of the shoulder girdle
• Function is related to the glenohumeral joint where the rotator cuff muscles both stabilize and execute motion
• Injuries of the rotator cuff are common and can interfere with normal biomechanics
• All muscles originate on the scapula and insert on the tuberosities of the humerus
• Part of the intrinsic muscles of the shoulder

Supraspinatus Muscle

• Origin: supraspinatous fossa of scapula
• Insertion: greater tubercle of humerus
• Innervation: suprascapular nerve
• Function
  • Initiation of abduction of arm to 15° at glenohumeral joint
  • Stabilization of humeral head in glenoid cavity

Anatomy of the rotator cuff muscles and tendons

Healthy anterior and posterior views of the rotator cuff muscles (left). Example of a rotator cuff tear

Infraspinatus Muscle

• Origin: infraspinatous fossa of scapula
• Insertion: greater tubercle of humerus
• Innervation: suprascapular nerve
• Function
  • External rotation of arm at glenohumeral joint
  • Stabilization of the humeral head in glenoid cavity.

Teres Minor Muscle

• Origin: lateral border of scapula
• Insertion: greater tubercle of humerus
• Innervation: axillary nerve
• Function
  • External rotation and adduction of arm at glenohumeral joint
  • Stabilization of the humeral head in glenoid cavity

Subscapularis Muscle

• Origin: medial two-third of the subscapular fossa
• Insertion: lesser tubercle of the humerus
• Innervation: upper and lower subscapular nerves
• Function
  • Internal rotation of arm
  • Stabilization of humeral head in glenoid cavity

Normal Shoulder Anatomy. A. This drawing shows the rotator cuff muscles in a sagittal plane (anterior is on the left). C, coracoid; A, acromion; H, humeral head. B. This sagittal T1WI through the glenoid shows the normal cuff musculature (SUB, subscapularis; SUP, supraspinatus; IS, infraspinatus, T, teres minor, C, coracoid process, G, glenoid).

Muscles of the rotator cuff

Function

• Stabilize and center the humeral head in the glenoid cavity
• Tighten the joint capsule, preventing a pinch during shoulder movement
• Rotate the humerus with respect to the scapula
• Provide muscular balance
• Plays a major role in internal and external rotation
• The supraspinatus initiates abduction of the arm

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Clinical Significance

• Rotator Cuff Tear
• Rotator Cuff Tendonitis
• Calcific Tendinitis of the Rotator Cuff
• Subcoracoid Impingement Syndrome
• Rotator Cuff Arthropathy

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See Also

• Physical Exam Shoulder
• Shoulder Pain Main
• Shoulder Anatomy Main

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