Passive and active range-of-motion tests are routinely used to identify soft-tissue pathologies. Unfortunately, practitioners often do not derive the full benefits of the information they can acquire through these tests. An expanded understanding of joint biomechanics will help you gain much more valuable information in your range of motion evaluations that will greatly improve your treatment strategies. When certain soft-tissue pathologies are present, many joints have a characteristic pattern of limited movement. Each pattern of movement limitation is unique to a particular joint. This movement restriction is caused by dysfunction in the joint capsule. Consequently, it's called the joint's capsular pattern.

Anatomical Background

Diarthrodial (freely moveable) joints have a space between the two articulating bones. The joint capsule is a fibrous connective tissue that holds the two bones together. It is composed of two different tissues. The outermost layer is a tough connective tissue called the fibrous capsule and is mostly made of ligamentous fibers. Inside the fibrous capsule is another layer of tissue called the synovial membrane (Figure 1). This membrane is responsible for secreting synovial fluid, which helps to lubricate the joint, supply nutrients and remove metabolic wastes from the area.

The fibrous capsule is richly innervated so it can produce a great deal of pain if there is any damage to it. The synovial membrane, however, has very little, if any, innervation and so it is rarely a source of pain. However, any irritation or restriction of the synovial membrane may also affect the fibrous capsule and therefore cause pain. In fact, stretching a fibrously adhered or restricted joint capsule is thought to be the chief cause of pain in osteoarthritis. Damage or dysfunction to the fibrous capsule or synovial membrane is then likely to produce a capsular pattern of motion restriction.

Biomechanical considerations

Not all joints have capsular patterns. The pattern appears to be more characteristic of joints with significant range of motion. For example, the sacroiliac joint, which is more of a tight and fibrous articulation with very little movement, does not have a capsular pattern. It makes sense that joints with very limited movement would not have a capsular pattern because it is very difficult to measure range of motion in them anyway. If the pattern of motion restriction in a joint is not the characteristic capsular pattern for that joint, the restriction is referred to as a non-capsular pattern. A non-capsular pattern would exist in a situation where there was joint or soft-tissue pathology but the joint capsule was not the primary tissue at fault.

The shoulder (glenohumeral joint) has the greatest range of motion of any joint in the body. Consequently this is also the joint where the capsular pattern is most important to evaluate, and where capsular pattern evaluations are used most frequently. Capsular patterns are also very important in the shoulder because unlike most other joints where motion is first limited by muscles becoming taut, it is actually the joint capsule that can limit shoulder motion in certain directions before the muscles become fully stretched.

In the shoulder, the capsular pattern dictates that motion restrictions occur first in lateral rotation, then in abduction, and third in medial rotation. In the early stages of a capsular restriction you may only see limitations to external rotation. As the condition progresses, there would be further limitations including abduction and eventually medial rotation. If an individual has a significant limitation to abduction, but no problem with lateral rotation, this would be considered a non-capsular pattern. As a result, this pathology is probably not primarily a joint capsule pathology. A much more likely cause would be some type of external structure causing the movement restriction such as an impingement problem under the acromion process.

Putting The Information To Use

In many cases, massage practitioners are not likely to be treating internal joint pathologies that involve joint capsule damage. However, certain conditions such as adhesive capsulitis (frozen shoulder), directly involve the joint capsule. There are effective massage treatment strategies for adhesive capsulitis, so it will be very helpful to identify if the joint capsule is involved. One of the big advantages of understanding the capsular pattern in this condition is you can continually monitor range of motion in the capsular pattern to measure how successful your treatment is at improving range of motion and reducing the capsular restriction.

Muscles are also a common limiting factor in joint range of motion. Consequently, muscular restrictions could mimic or magnify the capsular pattern of restriction. When performing range of motion evaluations, be sure to consider the musculotendinous unit, as well as ligamentous/capsular restrictions. There are a number of resources that have lists of capsular patterns for specific joints. The resources indicated here have charts or lists of capsular patterns that are very informative.

References

1. Lowe W. Orthopedic Assessment in Massage Therapy. Sisters, OR: Daviau-Scott; 2006.
2. Magee D. Orthopedic Physical Assessment. 3rd ed. Philadelphia: W.B. Saunders; 1997.
3. Petty N, Moore A. Neuromusculoskeletal Examination and Assessment. Edinburgh: Churchill Livingstone; 1998.