ROTATOR CUFF

GENERAL INFORMATION

The rotator cuff is a group of muscles and tendons located in the shoulder region. It consists of four muscles that work together to stabilise the shoulder joint and facilitate its movements. The rotator cuff muscles are the supraspinatus, infraspinatus, teres minor, as well as subscapularis.

ORIGIN

• Supraspinatus: Originates from the supraspinous fossa of the scapula.

• Infraspinatus: Originates from the infraspinous fossa of the scapula.

• Teres Minor: Originates from the lateral border of the scapula.

• Subscapularis: Originates from the subscapular fossa of the scapula.

INSERTION POINT

• Supraspinatus: Inserts into the greater tuberosity of the humerus.

• Infraspinatus: Inserts into the greater tuberosity of the humerus.

• Teres Minor: Inserts into the greater tuberosity of the humerus.

• Subscapularis: Inserts into the lesser tuberosity of the humerus.

MAJOR ARTERIES

The rotator cuff muscles receive their blood supply from various arteries. It includes the branches of the subscapular artery as well as the suprascapular artery.

NEURAL INNERVATION

The rotator cuff muscles are innervated by nerves arising from the brachial plexus.

• Supraspinatus: Suprascapular nerve (C5-C6).

• Infraspinatus: Suprascapular nerve (C5-C6).

• Teres Minor: Axillary nerve (C5-C6).

• Subscapularis: Subscapular nerves (C5-C6).

TRIGGER POINT

Trigger points can develop in the rotator cuff muscles, causing localised pain and tenderness. These trigger points can be associated with muscle overuse, poor posture, or trauma.

CONCENTRIC FUNCTION

Contraction of the muscles results in the initiation and control of shoulder movements, including abduction, adduction, internal rotation, as well as external rotation.

ECCENTRIC FUNCTION

The rotator cuff muscles have a vital eccentric function during controlled shoulder movements, providing stability and controlling the speed and range of motion.

ISOMETRIC FUNCTION

Isometric contraction of the rotator cuff muscles provides stability and support to the shoulder joint, maintaining proper alignment as well as preventing excessive movement.

RELATED MUSCLE SCIENTIFIC NAMES

• Supraspinatus: This muscle is involved in abducting the arm, particularly the first 15 degrees, and plays a crucial role in shoulder joint stabilisation.

• Infraspinatus: Crucial for external rotation of the shoulder, this muscle also helps stabilise the shoulder joint, preventing dislocation.

• Teres Minor: Aids in external rotation and adduction of the shoulder and works alongside the infraspinatus to stabilise the joint.

• Subscapularis: The most significant and vital rotator cuff muscle, It performs internal rotation and adduction of the shoulder as well as is essential for maintaining joint stability.

ANTAGONIST

• Deltoid: This muscle is primarily responsible for shoulder abduction and flexion, working against the rotator cuff muscles during various movements to ensure balanced muscle function.

• Pectoralis Major: Engages in flexion, adduction, and internal rotation of the shoulder, opposing the external rotation and stabilisation provided by the rotator cuff muscles.

COMMON INJURIES

• Rotator cuff tears: Partial or complete tears in one or more of the rotator cuff tendons, often due to trauma or degenerative changes.

• Rotator cuff impingement: Compression of the rotator cuff tendons and structures, resulting in inflammation and pain.

• Rotator cuff tendonitis: Inflammation of the rotator cuff tendons due to overuse, repetitive motions, or poor shoulder mechanics.

EXERCISES

• External rotation exercises: Use resistance bands, dumbbells, or cables to strengthen the external rotators (infraspinatus and teres minor).

• Internal rotation exercises: Use resistance bands, dumbbells, or cables to strengthen the internal rotators (subscapularis).

• Scapular stability exercises: Focus on strengthening the muscles around the scapula to support the rotator cuff and improve shoulder mechanics.

• Prone Y/T/W exercises: Enhance scapular stability and shoulder muscle balance by lifting the arms in Y, T, or W positions while lying face down.

• Shoulder blade squeezes: Promote scapular retraction and shoulder stability by pulling the shoulder blades together and holding the position.

STRETCHES

• Cross-body stretch: Bring the affected arm across the chest to stretch the posterior shoulder muscles.

• Sleeper stretch: Lie on the side with the affected arm bent at the elbow and gently push the hand towards the floor.

• Doorway stretch: Stand in a doorway with the arms at 90 degrees and gently lean forward to stretch the chest and front shoulder.

• Overhead stretch: Raise the affected arm overhead and use the opposite hand to pull the elbow towards the opposite side gently.

• Posterior capsule stretch: Hold the elbow of the affected arm with the opposite hand and pull it across the body to stretch the back of the shoulder.