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Rotator Cuff - want to learn more about it?

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Rotator Cuff

In the human body, the rotator cuff is a functional anatomical unit located in the upper extremity.

Its function os related to the glenohumeral joint, where the muscles of the cuff function both as the executors of the movements of the joint and the stabilization of the joint as well.

Injuries of the rotator cuff interfere with the function of the glenohumeral joint and correspond with inability to perform the movements associated with this joint.

Key Facts
Subscapularis muscle Origin: subscapular fossa
Insertion: lesser tubercle of the humerus
Function: internal rotation of the arm
Teres minor muscle Origin: lateral scapular border
Insertion: greater tubercle of the humerus
Function: external rotation of the arm
Supraspinatus muscle Origin: supraspinatous fossa
Insertion: greater tubercle of the humerus
Function: abduction of the shoulder over 60 degrees
Infraspinatus muscle Origin: infraspinatous fossa
Insertion: greater tubercle of the humerus
Function: external rotation of the arm
General function of the cuff Stabilization and centralization of the humeral head in the glenoid cavity during movements

The following article describes the anatomy, including the origins and insertions, together with the function and pathologies of the rotator cuff.

Origins and insertions

These muscles all originate from the scapula and insert in the humerus.

Recommended video: Rotator cuff muscles
Origins, insertions, innervation and functions of the rotator cuff muscles.

Subscapularis muscle

The subscapularis muscle is very important for the internal rotation of the humerus. It arises from the subscapular fossa and inserts on the lesser tubercle of the humerus.

Teres minor muscle

The teres minor muscle originates from the lateral scapula border and inserts on the greater tubercle of the humerus.

Supraspinatus muscle

The supraspinatus muscle has its origin in the supraspinatous fossa and inserts on the greater tubercle of the humerus – similar to the teres minor muscle.

Infraspinatus muscle

The fourth muscle of the rotator cuff is the infraspinatus muscle. It originates in the infraspinatous fossa of the shoulder blade and inserts on the greater tubercle as well.

Functions

The main function of the rotator cuff is to stabilize and center the humeral head in the joint socket, the glenoid cavity. In addition, the muscles tighten the joint capsule preventing a pinch during shoulder movements.

Certainly the rotator cuff – as the name suggests – plays a major role in the internal and external rotation of the upper arm in the shoulder joint. All the muscles mentioned above fulfill different functions.

The subscapularis muscle is a powerful internal rotator which also supports the upper arm during abduction and adduction. Conversely, the teres minor muscle’s function consists primarily of external rotation, partly retroversion and adduction as well.

The supraspinatus muscle performs abduction of the shoulder, especially abduction over 60 degrees. Finally, the infraspinatus muscle is a strong external rotator and additionally assists in both abduction and adduction.

Clinical aspects

When looking at pathologies of the rotator cuff – as in all joints - one needs to differentiate between degenerative and traumatic lesions. Here are two examples:

An example of a degenerative disease of the rotator cuff is the subacromial impingement syndrome. There the supraspinatus muscle tendon gets impinged at the acromion. This process is commonly caused by a thickened tendon or an inflammation of the overlying bursa leading to an enlargement, thus compressing the subacromial space.

Another possible cause for an impingement is a bony subacromial spur resulting in a narrowing of the nerve with pain. A positive Neer sign when elevating the shoulder above 120 degrees is characteristic in the impingement syndrome.

The rotator cuff tear is an example of a traumatic lesion of the rotator cuff where it comes to a rupture of one or more tendons up to the point of a complete tear of the rotator cuff muscles. Often those ruptures have been preceded by degenerative changes in the rotator cuff. The treatment can be either of conservative or surgical nature (e.g. transosseous fixation), depending on the severity of the rupture and the patient’s age.

Even though the rotator cuff consists only of four muscles, it plays an essential role in the stability and mobility of the most flexible joint in the human body: the shoulder.

Rotator Cuff - want to learn more about it?

Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster.

Sign up for your free Kenhub account today and join over 852,397 successful anatomy students.

“I would honestly say that Kenhub cut my study time in half.” – Read more. Kim Bengochea Kim Bengochea, Regis University, Denver

Show references

References:

  • Benninghoff/Drenckhahn: Anatomie, Band 1, 16. Auflage, Urban & Fischer Verlag (2003)
  • Berchtold: Chirurgie, 6. Auflage, Elsevier Verlag (2008)
  • Rössler H., Rüther W. [Hrsg.]: Orthopädie und Unfallchirurgie, 19. Auflage, Elsevier Verlag (2005)

Author & Layout:

  • Christopher A. Becker
  • Achudhan Karunaharamoorthy

Illustrators:

  • First Illustration Gallery - Yousun Koh, Paul Kim
  • Second Illustration Gallery - Yousun Koh
  • Third Illustration Gallery - Yousun Koh, Paul Kim
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Related Atlas Images

Muscles of the arm and the shoulder

Main muscles of the upper extremity

Humerus and scapula

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