Shoulder Pain

Cause: Mainly Muscular (incl. tendons)

1.

Shoulder / rotator cuff conditions

The 'shoulder cuff' is also known as the 'rotator cuff' and consists of a group of muscles and tendons attached to the bones that meet at the shoulder joint. The muscles and tendons of the shoulder cuff enable movement at the shoulder joint while also keeping the shoulder joint (a synovial joint) stable.

There are several types of damage / injuries to the shoulder cuff that can result in shoulder pain, such as:

• Compression of rotator cuff - e.g. immediately below the acromion process ('subacromial'), below the acromioclavicular joint, or within the coracoacromial ligament.
• Rotator cuff tears - can result from violent trauma e.g. in the case of some sports-related injuries, or unexpected motion e.g. to falls suffered by some elderly people.

2.

Frozen Shoulder

Frozen shoulder (also known as adhesive capsulitis) is a relatively common condition in which a shoulder - often, but not necessarily, on the person's non-dominant side, e.g. left- for right-handed people - becomes stiff and painful while movement at that shoulder joint is reduced, often severely reduced - even to the extent of becoming immoveable in some cases, hence described as "frozen". The severity and duration of the symptoms of 'frozen shoulder' vary considerably. It occurs most commonly in people between the ages of 40 and 65, with women generally being affected more than men. Frozen shoulder involves shoulder pain, though that is not the only symptom.

3.

Ruptured biceps tendon

A biceps tendon is a section of connective tissue that connects the biceps muscle to bone.
There are two biceps tendons, one at each end of the biceps muscle, i.e. a proximal biceps tendon at the shoulder joint, and a distal biceps tendon at the elbow. A ruptured biceps tendon is one that is damaged causing the tendon - and therefore, in turn, the biceps muscle to which it is attached - to separate from the bone. As a result the biceps muscle is unable to exert its usual forces on the bone so certain movements are weakened, reduced or prevented. Such an injury tends to be painful. Due to its proximity to the shoulder joint this may be a cause of shoulder pain. Even if not sufficiently damaged to cause complete separation from the bone, injury to biceps tendons can cause considerable shoulder pain.

Cause: Mainly Skeletal

4.

Osteoarthritis

Osteo-arthritis generally is due to wear of the articulatory cartilage, and may be primary, or may occur secondarily to abnormal load to the joint or damage to the cartilage from inflammation or trauma. It can result in painful joints (in this case shoulder pain), stiffness and restricted movement.

• Osteoarthritis of the acromioclavicular joint
  can lead to pain on/after movement of the shoulder, localized tenderness and prominence of the affected area.
• Osteoarthritis of the glenohumeral joint
  is less common than osteoarthritis of the acromioclavicular joint but may occur due to e.g. damage to the head of the humerus bone due to insufficient blood supply (i.e. avascular necrosis).

5.

Rheumatoid arthritis of the shoulder

Rheumatoid arthritis (RA) is more common in the shoulder region than osteoarthritis. RA generally is a disease of the synovial lining of joints resulting in affected joints becoming painful, swollen, and stiff. Progression of RA can result in damage to the ligaments supporting the joints and erosion of the bone, leading to deformity of the joints. RA affects the shoulder joint in the same way as other joints, hence can lead to shoulder pain.

6.

Dislocation of the shoulder

In general, joint dislocation (sometimes referred as 'luxation', from Latin) happens when the bones forming a joint are substantially displaced or misaligned e.g. due to a sudden impact. A subluxation is a partial dislocation.

When a shoulder is dislocated the humerus (see arm bones) is separated from the scapula (shoulder bone) at the glenohumeral joint (where the head of the humerus articulates with the glenoid cavity). The shoulder joint has a very wide range of motion hence is especially susceptible to dislocation and subluxation, which can be extremely painful. Dislocation of the shoulder joint is good example of a cause of shoulder pain.

7.

Klippel-Feil syndrome - Uncommon

Klippel-Feil Syndrome is a condition of the cervical spine (neck) and so also included on the page about causes of neck pain. It is a rare congenital abnormality that may be associated with other skeletal abnormalities such as scoliosis (curvature of the spine), spina bifida, Sprengel's shoulder, cleft palate and other conditions of e.g. the brain and spinal cord, arms, legs, and fingers.

8.

Sprengel Shoulder - Not necessarily painful, yet can still restrict movement

Sprengel's shoulder (sometimes called Sprengel's Deformity) is a congenital abnormality of the shoulder due to incomplete descent of the scapula during fetal development. Normally the scapula descends from the neck in the 3rd fetal month but in the case of a Sprengel shoulder the undescended scapula (often just on one side of the body) remains higher and smaller than the normally one. Although the incompletely descended scapula may move painlessly, the range of movement at the affected shoulder joint may be limited.

Cause: Nerves / Combination of causes / Other

9.

Cervical Spondylosis

Cervical spondylosis is one of the most common causes of neck and shoulder pain. It results from 'wear and tear' of the cervical vertebrae and the intervertebral discs that separate them in the neck so is also included on the page about causes of neck pain. Cervical spondylosis is sometimes considered a "normal part of the ageing process" and can have various degrees of severity with symptoms ranging from mild to extreme. In the case of shoulder pain due to cervical spondylosis, the pain may be referred from irritated nerve roots, affecting both the neck and shoulder.

- Bones / Nerves

10.

Winged Scapula - Not always painful, but may restrict movement and / or strength

A winged scapula is a relatively rare condition in which the shoulder blade, or shoulder bone (which is also known as the scapula) protrudes from a person's back in an abnormal position. The severity of "winged scapula", which is not always painful, can vary considerably. If serious, it can result in reduced movement and/or strength and so adversely affect the person's ability to move heavy objects or even perform some essential tasks such as dressing and washing.

A common cause of winged scapulae is paralysis of the serratus anterior muscle, located on the anterior of the body. This may, in turn, be caused by damage to the long thoracic nerve.

- Muscles / Nerves

11.

Infections in/affecting the shoulder joint - Uncommon

Infections in the shoulder region causing shoulder pain are not common. These are mentioned for completeness:

• Staphylococcal osteitis e.g. staphylococcal osteitis of the proximal humerus (hence in shoulder region)
• Tuberculosis of the shoulder, now rare
• Gonoccal arthritis of the shoulder, also uncommon.

- Pathogens