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Rotator Cuff Muscles

The rotator cuff is another name for a cluster of 4 different muscles and their tendons that play an important role in providing strength and stability in the shoulder movement.

SITS muscles is an abbreviation for this group of muscles with reference to the first letter of their names (Supraspinatus, Infraspinatus, Teres minor and Subscapularis). The muscles originate from the scapula and connect to the head of the humerus, forming a cuff at the glenohumeral joint.

The Rotator Cuff Muscles


Supraspinatus is a small muscle which originates from medial two-thirds of the supraspinous fossa of the scapula and is inserted into the greater tubercle of the humerus.


The infraspinatus muscle is a thick triangular muscle which originates from the infraspinous fossa and is inserted on to the middle facet of the greater tubercle of the humerus.

Teres Minor

The Teres minor muscle originates from the upper two-thirds of the lateral border of the scapula and is inserted into the inferior facet of the greater tubercle of the humerus.


The subscapularis muscle is a bulky triangular muscle originates from medial two-thirds of the costal surface of the scapula and is inserted into the lesser tubercle of the humerus.


External rotation, internal rotation, flexion and abduction are different types of upper extremity movements that are carried out by the rotator cuff muscles. They play a crucial role in almost every type of shoulder movement. Every muscle needs to have balanced strength and flexibility so as to maintain the functioning of the entire shoulder girdle.

Rotator Cuff Muscles

Rotator Cuff Muscles

These muscles work as a team because they are responsible for making your shoulder joint stable. They hold the head of the humerus into the small glenoid fossa of the scapula to facilitate the range of motion in the glenohumeral joint and avoid mechanical obstruction.

Each muscle has a particular role to play. Take a look at the brief descriptions of the four muscles that make a complete rotator cuff muscle.

Supraspinatus: The main function of the supraspinatus muscle is to hold the humerus in its place and maintain the stability of the upper arm which ultimately helps to lift the arm.

Infraspinatus: Rotation and extension of the shoulder is the major function carried out by infraspinatus muscle.

Teres Minor: This is the smallest of all rotator cuff muscle. Its major function is to help in the rotation of the arm away from the body.

Subscapularis: This muscle keeps the upper arm intact to your shoulder blade and assists in rotation of the arm, hold it straight out and lower it.

Rotator Cuff Injury

In the above context, we learned about all the four muscles that form the rotator cuff muscles and help the movement and stabilization of the shoulder joint. Chronic overuse, acute injury or gradual aging can cause some serious damage to any one or all of the muscles as well as the ligaments that act as an attachment between the muscles and bone. The damage can lead to some serious pain and the person might find it difficult to move his arm or shoulder due to decreased range of motion.

Other muscles that are involved in movement and stabilization of the shoulder include the deltoid, teres major, corachobrachialis, latissimus dorsi, and pectoralis major.

Different problems can show up when the rotator cuff muscle is injured. These are:

  • The range of motion of the shoulder gets limited due to pain and spasms.
  • The muscles find it difficult to carry out small adjustments within the joint that facilitates the humeral head to move smoothly.
  • Collection of fluid within the joint due to inflammation causes the movements to limit.
  • There can be impingement on the rotator cuff muscles or the tendons that attach them to the bones. There are narrow bony spaces through which the tendons run, and any change in the movement of the humerus and scapula can cause these spaces to become even narrower.
  • Arthritis and calcium deposits that form over time restricts the range of motion. These calcifications may occur along the bony edges of the joint or within the tendons of the rotator cuff muscles.

Most discussed and treated injuries to the Rotator Cuff are often referred to as:

  • Rotator Cuff Tears
  • Rotator Cuff Tendinitis
  • Rotator Cuff Tendinopathy
  • Impingement syndrome

Symptoms of Rotator Cuff Injury

Acute rotator cuff tear

  • Symptoms can include a sudden feeling of tearing followed by severe pain commencing from the upper shoulder area down the arm toward the elbow. Difficulty in completing range of motion of the shoulder because of pain and muscle spasm.
  • Acute pain from bleeding and muscle spasm: This may resolve in a few days.
  • Abduction (raising the arm away from the side of the body) of the arm may become difficult due to large tears which cause significant pain and loss of muscle power.

Chronic rotator cuff tear

  • Generally, the pain gets worse in the night making it really difficult to sleep for the affected person.
  • Shoulders start getting weak and movement becomes difficult as the pain goes worse.
  • The decrease in the abduction of the arm which helps the arm to carry out so many activities.

Rotator cuff tendinitis

Women aged 35-50 years are more prone to Rotator cuff tendinitis.

A deep ache in the shoulder also felt on the outside upper arm over the deltoid muscle

Point tenderness may increase over the area that is injured

Pain develops slowly and gets worse with lifting the arm to the side or turning it inward.

Treatment of a Rotator Cuff Injury

The treatment of a rotator cuff injury commences with proper rest, ice and physical therapy to give strength to the muscles of the rotator cuff and to reestablish full range of motion of the shoulder. It may take weeks or longer to reach proper healing.

Some nonsurgical treatments can also be used rotator cuff injuries, including steroid injections to decrease inflammation in the tight spaces where the muscle tendons run across the shoulder joint, therapeutic ultrasound, shockwave therapy, and dry needling.

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