What is the rotator cuff?

The rotator cuff muscles of the shoulder are some of the most talked about muscles when it comes to tendon tears and impingements.   Fifty to seventy percent of shoulder issues treated by therapists are related to conditions of the rotator cuff muscles.  This high percentage of rotator cuff issues is not at all surprising due to the fact that the shoulder is a highly mobile joint and it relies on the rotator cuff for its stability.

The rotator cuff consists of four muscles that originate on the scapula (shoulder blade) and insert onto the humerus (upper arm bone) where the tendons form a cuff around the head (top portion) of the humerus and offer the primary source of stability for the shoulder joint. 

The four muscles that make up the rotator cuff are the:

  1. Supraspinatus
  2. Infraspinatus
  3. Teres Minor
  4. Subscapularis

The names of the four rotator cuff muscles make the acronym S.I.T.S, which is an alternative term, used to identify these muscles of the shoulder.

Repetitive overhead movements such as pitching, painting, tennis serves and lifting heavy objects overhead can lead to a repetitive strain injury of the rotator cuff. Pain, weakness, and loss of shoulder mobility are common complaints reported with a rotator cuff injury.  Many patients will first complain of a dull ache that radiates into the upper or lower aspect of the arm.  The ache is usually more painful after activity, at night when the individual lies on the affected shoulder, and with movements like reaching to get items off the top shelf or trying to put a coat on.

The three most common rotator cuff injuries that I treat in my practice are:

Rotator cuff tendonitis:

Tendonitis (in any tendon) is simply acute inflammation or swelling of the affected tendon.  After an activity or repetitive overhead motion one or more of the rotator cuff tendons may develop tiny micro tearing, which in turn will cause the tendon to become inflamed and sore. If the tendonitis is mild it will usually only become painful after activity and disappear with rest and if it is severe it will become a chronic source of pain that affects athletic and daily activities.

Rotator cuff impingement:

Tendon impingement occurs when a tendon becomes constricted by its surrounding structures (often bones). The most common rotator cuff tendon that becomes impinged is the supraspinatus.  The supraspinatus tendon must travel under the acromion  (the top lateral bone of the shoulder) to insert onto the head of the humerus, which leaves the supraspinatus vulnerable to impingement especially when the tendon is inflamed and enlarged after an injury or repetitive strain.

Rotator cuff tear:

The most common rotator cuff tear occurs in the supraspinatus tendon.  Before tendons of the rotator cuff tear they usually have been affected by repetitive strain that has caused the tendon to fray or micro tear.  As the strain on the tendon(s) continues it eventually tears the tendon(s) either partially or completely.


In my next article (in 2 weeks) I will discuss treatment for frozen shoulder.


For more information on rotator cuff injuries or to book an appointment you can contact Ryan Samuels at his office (250) 860 2212 or via his website:www.kelownaacupunctureclinic.com   



This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.

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About the Author

Ryan Samuels is a Registered Acupuncturist and Chinese Medical Herbalist (R.Ac, R.TCMP) at KLO Chiropractic Centre in Kelowna. He holds a Doctor of Traditional Chinese Medicine diploma, and has a special interest in the treatment of digestive issues, neuropathy, acute & chronic pain, sports injuries, and migraines.  All treatments with Ryan are individualized and designed around your current physical and mental well being. 

Website link:  http://www.kelownaacupunctureclinic.com/

Contact Email:  [email protected] 

The views expressed are strictly those of the author and not necessarily those of Castanet. Castanet does not warrant the contents.

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