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Rotator cuff

Medically Reviewed by Anatomy Team

  • Last updated on January 28, 2025

Table of Contents

The rotator cuff is a group of four muscles and their associated tendons that stabilize the shoulder joint and facilitate its movements.[2] These muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis, collectively known as the SITS muscles. The rotator cuff is critical for maintaining the alignment of the humeral head within the shallow glenoid cavity during arm movements. Its tendons merge to form a cuff-like structure around the shoulder joint, ensuring stability and dynamic control.

Location

The rotator cuff is located in the shoulder, surrounding the glenohumeral joint. The muscles originate from the scapula and insert into the greater and lesser tubercles of the humerus, forming a protective and stabilizing sleeve over the joint.

Structure and Anatomy

The rotator cuff is a complex anatomical structure comprising four muscles and their associated tendons. These components work together to stabilize and support the shoulder joint while enabling a wide range of movements.

Muscles of the Rotator Cuff

The rotator cuff includes four muscles collectively referred to as the SITS muscles: supraspinatus, infraspinatus, teres minor, and subscapularis.

Supraspinatus

  • Origin: Supraspinous fossa of the scapula.
  • Insertion: Superior facet of the greater tubercle of the humerus.
  • Anatomy: The tendon passes under the acromion and over the shoulder joint to attach to the humerus.
  • Features: Occupies a narrow space, making it prone to impingement injuries.[3]

Infraspinatus

  • Origin: Infraspinous fossa of the scapula.
  • Insertion: Middle facet of the greater tubercle of the humerus.
  • Anatomy: Covers the posterior aspect of the shoulder joint.

Teres Minor

  • Origin: Lateral border of the scapula.
  • Insertion: Inferior facet of the greater tubercle of the humerus.
  • Anatomy: Positioned below the infraspinatus and blends with its tendon.

Subscapularis

  • Origin: Subscapular fossa on the anterior surface of the scapula.
  • Insertion: Lesser tubercle of the humerus.
  • Anatomy: The largest rotator cuff muscle, located on the anterior aspect of the shoulder joint.

Tendons of the Rotator Cuff

The tendons of the rotator cuff muscles converge to form a continuous cuff-like structure around the head of the humerus.[5]

  • Insertion Points:
    • Supraspinatus, infraspinatus, and teres minor tendons insert on the greater tubercle.
    • Subscapularis tendon inserts on the lesser tubercle.
  • Interweaving Fibers: The tendons interweave with the capsule of the shoulder joint, enhancing stability.

Capsule of the Shoulder Joint

  • The rotator cuff tendons blend with the fibrous capsule of the shoulder joint.
  • This integration helps maintain joint integrity and prevents dislocation during dynamic arm movements.

Bursae Associated with the Rotator Cuff

  • Subacromial Bursa: Lies between the supraspinatus tendon and the acromion. It reduces friction during shoulder movement.
  • Subdeltoid Bursa: Located beneath the deltoid muscle, also minimizing friction.

Blood Supply

Innervation

  • Supraspinatus and Infraspinatus: Innervated by the suprascapular nerve (C5, C6).
  • Teres Minor: Innervated by the axillary nerve (C5, C6).
  • Subscapularis: Innervated by the upper and lower subscapular nerves (C5, C6).

Arrangement and Orientation

  • The rotator cuff forms a nearly continuous sleeve around the shoulder joint:
    • Superiorly: Supraspinatus.
    • Posteriorly: Infraspinatus and teres minor.
    • Anteriorly: Subscapularis.

Function

Stabilization of the Shoulder Joint
The rotator cuff maintains the humeral head securely within the shallow glenoid cavity, ensuring stability during arm movements.

Facilitation of Shoulder Movements
The rotator cuff muscles work together to enable a wide range of shoulder motions:

  • Supraspinatus: Assists in initiating arm abduction (raising the arm away from the body).
  • Infraspinatus: Facilitates external rotation of the arm.
  • Teres Minor: Aids in external rotation and assists in adduction.
  • Subscapularis: Responsible for internal rotation of the arm.[8]

Dynamic Control
During shoulder movements, the rotator cuff muscles counteract the upward pull of the deltoid muscle, preventing the humeral head from impinging against the acromion.

Support for Overhead Activities
The rotator cuff provides strength and stability required for repetitive overhead actions, such as throwing, lifting, and swimming.

Joint Compression and Positioning
By compressing the humeral head against the glenoid, the rotator cuff minimizes joint laxity and enhances precision in movement.

Clinical Significance

The rotator cuff plays a critical role in shoulder stability and function, making it clinically significant in various contexts:

  • Rotator Cuff Tears:
    • One of the most common shoulder injuries, particularly in athletes and older adults. Tears can range from partial to full-thickness and often result from repetitive overhead motions or trauma. Symptoms include pain, weakness, and limited range of motion.
  • Rotator Cuff Tendinitis:
    • Inflammation of the tendons, often caused by overuse or impingement, can lead to pain and reduced shoulder mobility. Common in athletes, especially in sports like baseball and tennis.
  • Impingement Syndrome:
    • Occurs when the tendons of the rotator cuff become compressed, typically beneath the acromion. This leads to pain, inflammation, and difficulty with overhead movements.
  • Frozen Shoulder (Adhesive Capsulitis):
    • Scar tissue formation and stiffening of the shoulder joint, often related to rotator cuff dysfunction, which limits movement and causes pain.[1]
  • Shoulder Instability:
    • Damage to the rotator cuff can lead to instability, making the shoulder prone to dislocations, particularly in athletes or individuals with a history of repetitive shoulder use.
  • Surgical Repair and Rehabilitation:
    • Rotator cuff injuries may require surgical intervention for tendon repair, followed by extensive rehabilitation to restore shoulder strength and function.[4]

References

  1. Kibler, W. B., & Sciascia, A. (2019). Disorders of the Shoulder: Diagnosis and Management (3rd ed.). Wolters Kluwer Health. ISBN 9781975136475.
  2. Rockwood, C. A., Matsen, F. A., Wirth, M. A., & Lippitt, S. B. (2017). The Shoulder (5th ed.). Elsevier. ISBN 9780323395854.
  3. Burkhart, S. S., Lo, I. K., Brady, P. C., & Denard, P. J. (2017). Burkhart’s View of the Shoulder: A Cowboy’s Guide to Advanced Shoulder Arthroscopy (2nd ed.). Wolters Kluwer. ISBN 9781496380487.
  4. Magee, D. J. (2021). Orthopedic Physical Assessment (7th ed.). Elsevier. ISBN 9780323776158.
  5. DeLee, J. C., Drez, D., & Miller, M. D. (2020). DeLee and Drez’s Orthopaedic Sports Medicine: Principles and Practice (5th ed.). Elsevier. ISBN 9780323547321.
  6. Hoppenfeld, S., & Murthy, V. L. (2021). Treatment and Rehabilitation of the Rotator Cuff (4th ed.). Lippincott Williams & Wilkins. ISBN 9781975164362.
  7. Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2018). Clinically Oriented Anatomy (8th ed.). Wolters Kluwer. ISBN 9781496369659.
  8. Matsen, F. A., Fehringer, E. V., & Wirth, M. A. (2016). Shoulder Surgery: Principles and Techniques (2nd ed.). Lippincott Williams & Wilkins. ISBN 9781496326591.