The rotator cuff (many people call it rotator cup) is frequently injured in car, motorcycle and slip and fall accidents. Sometimes it is difficult proving the injury happened in the accident as opposed to some other time because the condition usually takes time to diagnose. We should probably start this discussion identifying the pertinent anatomy (structures) in the area.
The Shoulder is made up of bones, ligaments and muscles.
The bones of the shoulder include the long bone of the arm (humerus), the shoulder blade (scapula), and the collar bone (clavicle).
The shoulder has two primary joints. A joint is where two bones come together. First, we have the acromioclavicular joint (AC joint). This is where the acromion process of the scapula and the collar bone come together. Next, we have the glenohumeral joint, which is where the head of the humerus comes together with the glenoid process (fossa) of the scapula. Some folks also discuss the sternoclavicular joint but this joint is not part of today's discussion.
Ligaments attach from bone to bone and provide structure and protection to the joint. The purpose of the ligament is to check joint movement. An example of a ligament would be the acromioclavicular ligament which goes over the AC joint. If someone told you that you had an AC separation, you would have injured that AC ligament, which allowed the bones to separate.
Muscles are the primary movers of bones. The shoulder has a whole bunch of muscles, but today we are only going to discuss the four muscles of the rotator cuff.
Rotator Cuff Muscles
The four muscles of the rotator cuff go by an acronym SITS.
Supraspinatus – is the primary mover for the first few degrees of abduction of the shoulder. In order to understand abduction. Just put your arm down to your side and start bringing it up. The supraspinatus initiates the movement of the arm and then the middle deltoid muscle takes over.
Infraspinatus – is an external rotator of the shoulder. It imitates external rotation of the humerus.
Teres Minor – is also an external rotator of the shoulder.
Subscapularis – is an internal rotator of the shoulder and also holds the shoulder blade down with certain shoulder movements.
Mechanism of Rotator Cuff Injury
The typical mechanism of for a rotator cuff if falling onto an outstretched arm. Many times we see a foot player injuring the cuff when they are tackled and thrown onto the shoulder. We also see the injury in car and motorcycle accidents when the arm is forced up against the dashboard, vehicle door or ground.
The main culprit injured in the rotator cuff is the supraspinatus. A big part of the reason is the attachment sites of the muscle. The muscle originates on the back of the shoulder blade and attaches to the humeral head. In order for the tendon to get where it needs to go, it has to travel under the acromion process of the scapula. When you get the forces discussed above, the tendon can get pinched or impinged between the acromion process and the humerus causing the tendon to tear.
Rotator Cuff Symptoms
Folks with rotator cuff injuries will lose motion in the shoulder. They will have difficulty lifting their arm from their side, tucking in their shirt, combing the back of their hair and sleeping on the affected side.
Diagnosis of Rotator Cuff Injury
A rotator cuff injury can be suspected by history and physical examination, however, nowadays the diagnosis is usually confirmed by MRI.
Treatment of Rotator Cuff Injuries
Treatment depends on the nature and extent of the injury. A partial tear can usually be treated with medication, exercise and sometimes cortisone injections.
If the tear of the tendon is full or complete, surgery is usually indicated to put the tendon back together.
Settling a Rotator Cuff Injury Claim
Many rotator cuff injuries are difficult for insurance adjusters to understand because as we age we start to get a little impingement of the supraspinatus tendon anyway. Insurance adjusters take this finding and try to argue that the condition pre-existed the accident, which his why it is best of have a lawyer that understands the anatomy of the area and mechanism of injury so they don't fall for the insurance adjuster's baloney.
The value of a rotator cuff injury will depend on the following factors:
- The nature and extent of the injury;
- Underlying degeneration, if any;
- Whether there is a partial or complete tear;
- Whether surgery is indicated;
- Residual loss of function; and
- How any residual loss of function impacts the client's future?