July 2, 2009
The Cervical Spine " Part Two
Irritability of inflamed or injured facet joints is high in terms of easily and quickly flaring up into pain when subject to unusual stresses, but then later can react badly even to normal stresses. The typical symptoms are local tenderness and aching throughout the neck, across the shoulder blades, over the neck/shoulder area and upper arms. All this pain can cause the muscles to go into spasm which compounds the problem by facet joint compression with consequent enhancement of the pain and joint forces. Some patients have severe neck muscle spasm which presents as tight, hard muscles.
The overall delicate functioning of the neck can be badly disturbed by this muscle spasm, limiting its capacity to cope with sudden shocks. Muscles are more likely to remains contracted for longer than they should, rendering the neck more vulnerable to sudden jars and shocks. As the neck pain develops the person naturally guards their movement much more strongly which adds to the lack of normal movement as they limit arm activities. The interrelation of the thoracic and neck postures has important knock-on effects for neck pain syndromes as abnormal postures increase segmental stresses.
A lack of thoracic kyphosis can mean that the thoracic spine approaches its junction with the cervical spine above it in too vertical a position, forcing the neck to adopt a correspondingly more vertical posture than normal. The loads the neck bears are usually spread between the discs and the facet joints by the normal lordosis and if this is lost then increased loads may be thrown onto the discs, causing increased degenerative changes within them. The opposite, where an increased thoracic curve forces a correspondingly increased neck curve, is countered either by neck or lumbar extension.
Increased cervical and thoracic spinal curves result in a typical poor posture, particularly in sitting, of the head poking well forwards of the shoulders and trunk, requiring high levels of force to be developed in the supporting musculature of the neck to keep the head held in space. The biggest and strongest muscle is the upper trapezius and when it is working too hard it can develop local tender and painful spots which can refer pain elsewhere and are known as trigger points. The lower trapezius muscles can correspondingly become underactive, leading to a reduced level of control of the shoulder, neck and arm complex.
Our necks can be injured in a series of different methods, either suffering sideways forces involving twisting or shearing or longitudinal compression forces, or both. The outer disc walls are vulnerable to such injuries and so begins the sequence of degenerative events in the disc, the pain itself followed by both inhibition and overwork of the muscles, loss of range of motion and limitation of disc nutrition. Pain worsening leads to the extensor muscles of the neck increasing the vertical pressures by over contracting, pushing the vertebral levels together more closely. Segmental disc narrowing may lead to stiffness but can also cause hypermobility of the segments as the disc, having lost water content and ligamentous integrity, loses its role in stability.
When a segment suffers degenerative changes bony outgrowths can appear at its margins along the ligaments, outgrowths known as osteophytes. Segmental levels with significant movement abnormalities will tend to show osteophytic changes, perhaps reflecting an attempt by the body to give increased segmental stability by building a bony bridge along the ligament or disc wall between the segments. The nerve roots in the neck or the back can be impinged upon by osteophytes which can cause severe arm or leg pain, requiring surgery. Surgical management is not a regular approach to most osteophytes which may well be asymptomatic.
One a stiff spinal segment has become established this has knock-on consequences for the more posterior facet joints. The facet surfaces are forced into more pressured contact as the vertebrae become closer together with the gradual narrowing of the disc. As a compressed facet becomes gradually damaged and stiff the movements that it should perform have to be performed elsewhere, either higher or lower, in the spinal column. This allows the stiff segment to cause problems in several areas of the neck which were previously unaffected.
Filed under back pain and leg pain by Jonathan Blood Smyth
