Facet joints are very irritable, which means when they are injured or inflamed they very quickly cause pain in response to initially abnormal, but later to normal, stresses. This causes aching and local tender spots in the neck, shoulder areas, over the shoulder blades and upper arms. Pain also leads to secondary muscle spasm which compresses the joints together further and amplifies the stresses and the pain. Muscle spasm can be very dominant in some neck problems and can easily be felt as tough, hard muscular contraction which is permanently present when the neck is under load.
Muscle spasm disturbs the whole function of the neck, reducing its ability to iron out sudden stresses. Muscles which would naturally switch off after a time remain contracted and tense the neck, making it more sensitive to jars and sudden movements. As the neck becomes more irritable the person consciously becomes more guarded with their neck movements and their upper arm activities, magnifying the problem again. The interplay of neck and thoracic posture has important mechanical consequences for painful problems in the neck as it throws abnormal stresses on the cervical segments.
If the thoracic spine is much straighter than it typically is the reciprocal curves of the thorax and the neck can be lost, forcing the cervical spine to sit more vertically upon the thorax, without its typical lordosis. The lordosis distributes weight between the anterior discs and the posterior joints, preventing abnormal disc loading which can cause early degeneration and then secondary facet changes. Problems can also occur when the opposite anatomical misalignment occurs with an increased thoracic curve forcing a reciprocally increased cervical curve to maintain the face in a horizontal position.
With the poking neck syndrome occurring with an increased level of thoracic and cervical curves, the head is placed well forward of its support in the neck, forcing the main neck extensor muscles to over work to maintain their hold on head posture. The overuse of the upper trapezius muscles can cause trigger points to develop in the muscles, causing local and referred pain problems which can be very persistent. The overactivity of the upper part of the trapezius can cause a corresponding inhibition of the activity of the lower trapezius muscle which stabilises the scapula, enabling a good pattern of control for arm movement.
Neck injuries can occur in a variety of mechanisms, either the more vertical, compression like events or a sideways shearing and twisting incident. The disc outer walls are sensitive to these events and can be injured, starting the process of pain, muscular inhibition and muscular overactivity, reduced disc nutrition and loss of movement which progresses steadily to increased degenerative changes. As the pain progresses the neck extensor muscles add to the compression forces on the segments by becoming overactive, forcing the vertebrae closer together. Once a segmental disc has narrowed it may develop increased mobility rather than stiffness due to the reduction in strength of the disc unit when it loses its water content.
Segmental degeneration is often accompanied with time by the growth of osteophytes, outgrowths of bone, which sprout from the edges of the abnormal segment. An abnormally moving segment is likely to suffer this change and this may be an attempt by the bodys systems to improve the stability of the segment by splinting it with bone along the soft tissues nearby. The nerve roots exit from the intervertebral foramens each side of the spine and there are vulnerable to impingement at times by osteophytic outgrowth, causing severe nerve root pain in the arm. Surgical management of such impingement may be required in some people but overall this condition is not amenable to surgery.
The establishment of a stiff spinal segment in the neck forces the facet joints into an untenable position in terms of normal function. Compressed together by vertebral approximation secondary to disc narrowing, the facet surfaces suffer from the increased forces. The gradual joint damage reduces the movement available and this is picked up elsewhere in the spinal column, either lower down or higher up. This way previously normal joints can start to develop movement and structural abnormalities.
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