Shoulder pain is an extremely common symptom for people presenting to a chiropractor. Shoulder pain affects around 3 in 10 adults at some time during their lives. It is important to make an accurate diagnosis of the cause of your symptoms so that appropriate treatment can be directed at the cause.
Shoulder pain is the third most common cause of musculoskeletal consultation in primary care. 1% of adults with new shoulder pain consult their GP each year. The self-reported prevalence of shoulder pain is between 16% and 26%.
Shoulder pain isn’t always directly caused by a problem in the shoulder joint. Problems in the neck can cause pain that is felt over the shoulder blade or in the upper outer arm (this is known as referred pain). If shoulder pain is accompanied by a tingling sensation, this is also more likely to be caused by a problem in the neck.
Anatomy of the Shoulder
The two main bones of the shoulder are the humerus and the scapula (shoulder blade).
The joint cavity is cushioned by articular cartilage covering the head of the humerus and face of the glenoid. The scapula extends up and around the shoulder joint at the rear to form a roof called the acromion, and around the shoulder joint at the front to form the coracoid process.
The end of the scapula, called the glenoid, meets the head of the humerus to form a glenohumeral cavity that acts as a flexible ball-and-socket joint. The joint is stabilised by a ring of fibrous cartilage surrounding the glenoid called the labrum.
Ligaments connect the bones of the shoulder, and tendons join the bones to surrounding muscles. The biceps tendon attaches the biceps muscle to the shoulder and helps to stabilise the joint.
The rotator cuff is made up of four muscles. These individual muscles combine at the shoulder to form a thick “cuff” over this joint. The rotator cuff has the important job of stabilising the shoulder as well as elevating and rotating the arm. Each muscle originates on the shoulder blade, or scapula, and inserts on the arm bone, or humerus.
The four muscles that form the rotator cuff are the supraspinatus, infraspinatus, teres minor, and subscapularis.
The supraspinatus muscle originates above the spine of the scapula and inserts on the greater tuberosity of the humerus. The supraspinatus abducts, or elevates, the shoulder joint. It also works with the other rotator cuff muscles to stabilise the head of the humerus in the glenohumeral joint, or shoulder joint.
The infraspinatus muscle originates below the spine of the scapula, in the infraspinatus fossa, and inserts on the posterior aspect of the greater tuberosity of the humerus. The infraspinatus externally rotates the shoulder joint. It also works with the other rotator cuff muscles to stabilise the head of the humerus in the glenohumeral joint, or shoulder joint.
The teres minor muscle originates on the lateral scapula border and inserts on the inferior aspect of the greater tuberosity of the humerus. The teres minor muscle externally rotates the shoulder joint. It also works with the other rotator cuff muscles to stabilize the head of the humerus in the glenohumeral joint, or shoulder joint.
The subscapularis muscle originates on the anterior surface of the scapula, sitting directly over the ribs, and inserts on the lesser tuberosity of the humerus. The subscapularis muscle works to depress the head of the humerus allowing it to move freely in the glenohumeral joint during elevation of the arm. It also works with the other rotator cuff muscles to stabilise the head of the humerus in the glenohumeral joint, or shoulder joint.
Causes of Shoulder Pain
Shoulder pain can stem from one or more of the following causes:
- Strains from overexertion
- Tendonitis from overuse (RSI or repetitive strain injury)
- Shoulder joint instability
- Collar or upper-arm bone fractures
- Frozen shoulder
- Trapped nerves (also called radiculopathy)
- Referred Pain
Avoiding Shoulder Pain
- Avoid excessive unaccustomed activity with the hands above shoulder height e.g. doing tasks like painting the ceiling, hanging curtains and trimming the hedge in short periods of time
- If you exercise, ensure you balance your training programme to incorporate strength work for all muscle groups
- Take breaks from repetitive shoulder movements and heavy lifting
- Avoid excessive overhead activities
- Correct your posture – if you slouch, your ability to lift your arm above your head reduces by approximately 30 per cent. Sitting and standing in a good posture with your shoulders back will help your movement as well as prevent the tendons in your shoulder catching
- Try not to slouch as this squashes all the structures in your shoulder against the ridge above the joint, causing pain and irritation