What you need to know about your rotator cuff and shoulder impingement syndrome.
What is the rotator cuff?
The rotator cuff is a group of 4 muscles that originate on the shoulder blade and insert onto the head of the humerus. See the rotator cuff pictured below:
The 4 muscles of the rotator cuff can easily be remembered as the SITS muscles.
- Teres Minor
These muscles are important for pain free function of our shoulders. They are called a “cuff” because they surround the ball and socket joint of the shoulder and work together to keep the head of the humerus (the ball) centered in the glenoid of the shoulder blade (the socket). These muscles compress the ball into the socket to maintain integrity of the shoulder joint as the shoulder moves through its range of motion.
Our shoulders are designed for mobility. We have a huge amount of motion that can occur at the shoulder joint. Whether reaching above our head, behind our back, or across our body the four muscles of the rotator cuff most work together to maintain normal healthy function of our shoulders.
One more important point about the rotator cuff and its job of keeping ball centered in the socket. As you can see in the picture below, above the ball and socket joint of the shoulder is a roof. The roof is formed by the acromion (part of the shoulder blade) and the coracoacromial ligament. The space between the ball and socket and the acromion is known as the subacromial space. The rotator cuff keeps this space open by keeping the ball centered in the socket. There are a few different structures that live in the subacromial space: the subacromial bursa, the long head of the biceps tendon, and the supraspinatus muscle and its tendon.
What is impingement syndrome of the shoulder?
Shoulder impingement syndrome describes the condition of altered mechanics in the ball and socket of the shoulder joint causing a pinch to the structures in the subacromial space.There are different types of shoulder impingement and a number of different contributing factors to this condition.
Rotator cuff strength, rotator cuff tears, lack of shoulder range of motion, acromion anatomy, capsular stiffness, shoulder blade muscle strength/control and posture can all contribute to shoulder impingement syndrome.
Shoulder impingement syndrome will generally involve pain or limited motion due to pain with reaching above shoulder height or reaching behind the back. Common complaints can be reaching up to wash your hair in the shower, reaching into the back seat in the car, reaching for your seatbelt in the car or putting on and taking off a shirt or coat.
If you are having shoulder pain or finding daily activities and exercise to be painful or limited give us a call! Everyone with shoulder pain presents differently and as you now know there are a number of different factors that can contribute to shoulder impingement syndrome. A comprehensive exam including learning about your symptoms, measuring your range of motion and strength, and a physical exam will allow us to design a treatment plan customized to your shoulder.