Rotator cuff anatomy-SCIENCEROOTS

 What is rotator cuff  ?

It is also called  Musculotendinous cuff. Rotator cuff of the  shoulder is a fibrous sheath formed by  the  four flattened tendons. Rotator cuff blend with the capsule of the shoulder joint and strengthen it. 

Our upper arm bone, the humerus, is inserted into the socket of our shoulder blade of the scapula.  Rotator cuff muscles protect our arm from popping out of the socket, or glenoid, when we extend it out from our body. So its protect our arm.

The muscles which form the  cuff arise from the scapula  and inserted into the lesser and greater tubercles of the humerus bone. These muscles protect our arm from popping out of the socket, or glenoid, when we extend it out from our body. 

Anatomy of rotator cuff 

The muscles which form the  cuff arise from the scapula  and inserted into the lesser and greater tubercles of the humerus bone. All four muscles originate in your shoulder blade, but the other end of the muscle leads to different parts of your upper arm bone.

 these four muscles are:

• Subscapularis
• subscapularis is a large triangular-shaped muscle that lies below the other three muscles. It’s the strongest, largest, and most used of the four rotator cuff muscles. It participates in most shoulder motions but is especially important for rotation of our arm toward the midline of our body (medial rotation). Unlike the other three muscles, the subscapularis attaches to the front, not the back, of our upper arm.
• Infraspinatus 
• It is the main muscle responsible for lateral rotation of our arm away from the centreline of our body. It is a thick triangular muscle responsible for lateral rotation. It covers the back of our shoulder blade deep below the skin and close to the bone of our body.
• Teres minor
• It is a small, narrow muscle on the back of our shoulder blade just below the infraspinatus. It is also contributes to lateral (external) rotation of our arm.
• Supraspinatus 
• Supraspinatus is responsible for movement away from the centreline of our body ( that's called abduction). The supraspinatus produces about the first 15 degrees of motion. After that, our deltoid and trapezius muscles take over.

Their tendons, while crossing the shoulder joint, become flattened and blend with each other on one hand, and with the  capsule of the joint on the other hand, before reaching their points of insertion.

The muscles which form the  cuff arise from the scapula  and inserted into the lesser and greater tubercles of the humerus bone. All four muscles originate in your shoulder blade, but the other end of the muscle leads to different parts of your upper arm bone. They are:

• Subscapularis
• Infraspinatus
• Teres minor
• Supraspinatus

injuries

Tendinopathy

 this is often pain in and round the tendons. Tendinitis and tendinosis are variations. structure tendinitis is considered the mildest sort of structure injury. It can develop from:

age-related degeneration

overuse

repetitive motion

trauma

Impingement

 this happens when the highest of the shoulder (the acromion) rubs against the tendon and therefore the bursa and irritates the structure . Between 44 and 64 percentTrusted Source of all shoulder pain is assumed to return from subacromial impingement syndrome (SAIS), which is that the commonest shoulder disorder.

Bursitis

The bursa around the rotator cuff can fill with fluid and swell.

Bone spurs

These can form when rotator cuff tendons rub on the shoulder bones. Bone spurs don’t always cause a rotator cuff injury.

Partial tears of the rotator cuff tendons

The tendon is damaged or frayed but isn’t torn away from the bone.

Full-thickness tears

The tendon is completely torn from the bone. Chronic degeneration is usually the reason.