The Shoulder

How the shoulder works!

The shoulder is made up of three bones: the scapula (shoulder blade), the humerus (upper arm bone), and the clavicle (collarbone).

The rotator cuff connects the humerus to the scapula. The rotator cuff is formed by the tendons of four muscles: the supraspinatus, infraspinatus, teres minor, and subscapularis.

Tendons attach muscles to bones. Muscles move the bones by pulling on the tendons. The rotator cuff helps raise and rotate the arm.

As the arm is raised, the rotator cuff also keeps the humerus tightly in the socket of the scapula. The upper part of the scapula that makes up the roof of the shoulder is called the acromion.

A bursa is located between the acromion and the rotator cuff tendons. A bursa is a lubricated sac of tissue that cuts down on the friction between two moving parts. Bursae are located all over the body where tissues must rub against each other. In this case, the bursa protects the acromion and the rotator cuff from grinding against each other.

In order to know if you have injured your rotator cuff you should have it examined by a Doctor of Chiropractic. They will ask questions about your medical history, your injury, and your pain. Then they will perform a physical examination of the shoulder. The physical exam is most helpful in diagnosing a rotator cuff tear. A complete tear is usually very obvious. 

X-rays won't show tears in the rotator cuff. However, the Doctor of Chiropractic may want you to have a shoulder X-ray to see if there are bone spurs, a loss of joint space in the shoulder, or a down-sloping (hooked) acromion. These findings are associated with tears in the rotator cuff. An X-ray can also show if there are calcium deposits in the tendon that are causing your symptoms, a condition called calcific tendonitis. Further studies may include: an ultrasound and/or an MRI.

The shoulder is a joint than can be treated with a combination of many different treatments.  The treatment types are dependent on the injury.  These can include – the Interferential current machine, acupuncture, massage therapy, active release, and chiropractic to restore the joint motion, stretching, strengthening, and modifications to activities.

The shoulder joint is very complex and works with the shoulder blade, neck and upper back to co-ordinate movements.

The rotator cuff is made up of four muscles that ‘cuff’ the shoulder.  These muscles can be injured due to different factors.

 The shoulder
• A complex structure:  3 Bones, 3 Joints which attach it to the mid back and arm, 5 Ligaments, over 30 Muscles, 4 Bursa, 3 capsules.
• 75% of North Americans will experience shoulder problems requiring care at some point.
• The shoulder joint comprises the part of the body where the humerus attaches to the scapula.  The shoulder refers to the group of structures in the region of the joint.

The shoulder joint is made up of 3 bones: Collarbone (clavicle), Shoulder blade (scapula), Upper arm bone (humerus) 

• The bones of the shoulder are held in place by: muscles, ligaments, and tendons.
• Ligaments attach shoulder bones to each other, providing the main stability for the shoulder. The front of the joint capsule is anchored by three glenohumeral ligaments. 
• Tendons are tough cords of tissue that attach the shoulder muscles to bone and assist the muscles in moving the shoulder.
• There are 30 muscles providing movement and support for the shoulder complex. 
• The muscles that are responsible for movement in the shoulder attach to the scapula, humerus, and clavicle. The muscles that surround the shoulder form the shoulder cap and the underarm. 
• The capsule is a watertight sac (soft tissue envelope) that encircles the glenohumeral joint. It is lined by a thin, smooth synovial membrane. 
• Three main nerves begin together at the shoulder: the median nerve, the ulnar nerve, and the radial nerve. These nerves run under the collarbone and are known as the Brachial Plexus before they divide.
• The shoulder movement occurs as a result of all these structures and from the use of the ribs, thoracic spine, neck and even the elbow.  Often unresolved shoulder problems are a result of the other areas involved not being treated.   

Scapular-thoracic motion

• Scapular activity during shoulder motion is critical for normal shoulder function – shoulder moves 2/3 of the movement and the scapula the other 1/3 motion. 
• The scapulo-thoracic motion is the movement between the scapula (shoulder blade) and the thoracic spine. 
• The scapula moves with the shoulder in many daily and athletic activities. Anytime you raise your arm up this motion occurs!
• It is often over-looked in shoulder problems and that is one reason they do not resolve properly.

The Shoulder

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Clicking, crunchy noises?
Often patients complain of a clicking shoulder. The age at which the clicking began, whether they eventually became aware of it after an injury, and whether it's a painful click are all factors we consider when evaluating a clicking shoulder.

Under 25, clicking is probably more related to an instability problem than in later years in which loose bodies and a thickened bursa are frequent causes. A painful click represents some type of pathology. A painless click indicates internal imbalances in the shoulder with the joint, muscles, tendons and ligaments.

The clicking can also be caused by a loose body (some type of extra material in the shoulder) and these are usually visualized by radiography. 

The above causes of a click may also cause a palpable and audible crepitus (crunchy noise) at the same time.

A tear in the glenoid labrum can also cause a clicking shoulder. The labrum is a fibrous structure joined to the glenoid fossa (the socket of the shoulder blade which faces the ball of the shoulder bone). Its function is to deepen the concavity of the glenoid fossa (see picture to left), act as the origin for the some shoulder ligaments, and has a role in resisting forward movement of the ball of the shoulder (humeral head).

Often we are asked, Is it normal for my shoulder(s) to click? I have no pain associated with it.

The answer is: No, it is not normal, there is some type of underlying issue and with continued use can lead to future problems.

A complex structure: 
3 Bones, 3 Joints which attach it to the neck, mid back, elbow, arm and hand, 5 Ligaments, over 30 Muscles,
4 Bursa, 3 capsules.

75% of North Americans will experience shoulder problems requiring care at some point. In 2003, approximately 15.7 million people in North America sought care for shoulder problems.

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Forward Shoulders/Forward Neck

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Probably one of the most common postural distortions we see is the forward head, forward shoulders posture. This distortion often appears in teenagers and progresses to old age. This forward head/forward shoulders places stress on the neck joints—leading to early arthritis, shoulders, causes nerves to be pinched, the jaw muscles can be tight and can lead to tension headaches/ migraines.

This causes the chest to descend with the shoulder blade (scapula) shifting forward around the rib cage. In this position, the humerus rotates inward and the head and neck are brought forward.

This can be examined and worked on!

Scapulo-thoracic motion—often overlooked!

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The muscles and joints of the shoulder allow it to move through a remarkable range of motion, making it the most mobile joint in the body!

The six motions in performs are: flexion (bringing forward), extension (to go backwards), adduction (to bring together), abduction (to bring apart), medial rotation (inward), lateral rotation (outward).

One most often over looked movements of the shoulder, which is key to resolving shoulder problems is known as: Scapulo-thoracic motion. The Scapulo-thoracic motion is between the shoulder blade (scapula) and the thorax wall). The Scapulo-thoracic motion is a critical element for normal shoulder motion. During normal Scapulo-thoracic motion the shoulder moves 2/3 and the scapula 1/3 of the motion. When someone has a shoulder problem the mechanics are normally changed. 

This change is that the shoulder starts to move only 1/3 and the scapula 1/3. This places pressure/force on the scapula, thoracic shoulder problems spine, muscles in these areas and the tops of the shoulder. There would be tension in the tops of the shoulders due to over-use of other muscle groups.

A Shoulder Aggravating a Neck that Aggravates a Shoulder
The title of this article looks odd, usually when we attempt to find the source of pain in a shoulder; we also evaluate the cervical spine.

If motion testing of the cervical spine does not refer pain to the shoulder, and motion testing of the shoulder reduplicates the patient's shoulder pain, we would probably as- pain is localized in the shoulder.

It is very important to evaluate the neck as well, because muscles from the neck insert into the shoulder blade.

These muscles can shorten, causing rotation of the neck vertebrae and restrictions in the neck vertebrae can result.

Also the nerves from the neck supply the sensory sensation to the shoulder. So shoulder dis-comfort can often be referred from the neck due to nerve related issues. Many people who have their shoulder treated do not have full resolution of the shoulder because the neck and upper back are not evaluated and treated with their shoulder condition. It will often get better, but not be quite 100%.

The Shoulder

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Shoulder Mechanics

Whether throwing a ball, paddling a canoe, lifting boxes, or pushing a lawn mower, we rely heavily on our shoulders to perform a number of activities. Normally, the shoulder has a wide range of motion, making it the most mobile joint in the body. Because of this flexibility, however, it is not very stable and is easily injured. The shoulder is made up of two main bones: the end of upper arm bone (humerus) and the shoulder blade (scapula). The end of the humerus is round, and it fits into a socket in the scapula. The scapula extends around the shoulder joint to form the roof of the shoulder, and this joins with the collar bone (clavicle). Surrounding the shoulder is a bag of muscles and ligaments. Ligaments connect the bones of the shoulders, and tendons connect the bones to surrounding muscle. Four muscles begin at the scapula and go around the shoulder, where their tendons fuse to form the rotator cuff. When the shoulder moves, the end of the humerus moves in the socket. Very little of the surface of the bones touch each other. Ligaments and muscles keep the humerus from slipping out of the socket and keep the clavicle attached to the scapula.

To keep shoulders healthy and pain-free, it's important to know how to spot and avoid common injuries.

Recommended Treatments for Shoulder Injuries

Signs that you should seek treatment include:

1. Shoulder pain that persists beyond a few days

2. Recurring shoulder pain, even if it has a history of settling on its own

3. Inability to carry objects or use the arm

4. Injury that causes deformity of the joint

5. Shoulder pain that occurs at night or while resting

6. Inability to raise the arm

7. Swelling or significant bruising around the joint or arm

8. Signs of an infection, including fever, redness, warmth or swelling

Dr. Rodwin can assess your shoulder problem and will recommend treatments specific to your issues based on her diagnosis which may include: chiropractic adjustments, massage therapy, Active Release Treatment, acupuncture, stretches, etc. It is very important to seek out treatment early on before the problem becomes a chronic issue.

Common Injuries of the Shoulder

Bursitis: The most common diagnosis in patients with shoulder pain is bursitis or tendonitis of the rotator cuff. Bursitis is an inflammation of a fluid-filled sac, or bursa that lies between tendon and skin or between tendon and bone. Normally a bursa protects the joint and helps make movement more fluid.

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Rotator Cuff Tear: A Rotator cuff tear occurs when the tendons of the rotator cuff separate from the bone. Surgery is sometimes necessary for this condition.

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Shoulder Instability: Instability is a problem that causes a loose joint. Instability can be caused by a traumatic injury (dislocation), or may be a developed condition

Shoulder Dislocation: A dislocation is an injury that occurs when the top of the arm bone becomes disconnected from the scapula.

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Shoulder Separation: Also called an AC separation, these injuries are the result of a disruption of the Acromio-clavicular joint. This is a very different injury from a dislocation!

Arthritis: Shoulder arthritis is less common than knee and hip arthritis, but when severe may require a joint replacement surgery. Arthritis is a gradual narrowing of the joints and loss of protective cartilage in the joints about the shoulder.

Frozen Shoulder: Also called 'adhesive capsulitis,' this is a common condition that leads to stiffness of the joint.

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Motions of the Shoulder Explained

Normal movement of the shoulder requires fluent action at four different joints and these often are out of alignment with shoulder problems.

• Scapulo-thoracic Joint: Movement of the scapula (shoulder blade), gliding on the rib cage and with the thoracic spine (midback).  Normal motion is: for every 2/3 of gleno-humeral elevation (shoulder), there is 1/3 of scapulo-thoracic (midback with shoulder blade) elevation. Movements occurring here include elevation/depression, retraction/protraction and superior/inferior rotation. When someone undergoes a shoulder injury their body adapts and switches the mechanics from 2/3 shoulder motion to 1/3 shoulder motion and from 1/3 midback-shoulder blade motion to 2/3 midback-shoulder blade motion. Commonly this movement is not fixed completely for patients that have shoulder problems and this is the main reason why their problem does not go away.  The thoracic spine (mid back) needs to be treated as well to aid in resolving their shoulder issues.
• Acromio-clavicular Joint: Movement about this joint is very slight- but this synovial joint actually allows small amounts of superior and inferior glide.  When this goes out of alignment there can be discomfort or pain in the front of the shoulder.
• Sterno-clavicular Joint: This refers to the joint of the acromion at the manubrium of the sternum. Movements allowed here include elevation/depression, anterior/posterior translation and small amounts of rotation.  Problems in this area can lead to discomfort/pain in the front or the upper back area.
• Gleno-humeral Joint: Movement of the head of the humerus in the glenoid fossa.  Problems with this joint can lead to muscle imbalances and tightness in the muscles in the shoulder.

It is important with shoulder problems to evaluate the motion of all these shoulder joints to aid in resolving the shoulder problem.