Cervical Spine Anatomy Explained
The cervical spine is an extremely complex area of the body, with myriad structures, blood vessels, nerves, and tissues that can both cause, and be affected by, pathological changes in the neck. There are thirty-one segments of the spinal cord, eight of them existing in the cervical spine, along with seven cervical vertebrae and eight cervical spinal nerves. Between each vertebrae is an intervertebral disc which helps to keep the spine stable and absorb shock from bodily movements. Nerves exit the spine and spinal column through intervertebral foramen (in most cases) and are at peril of compression from conditions causing stenosis of the spine such as:
The vertebrae that make up the cervical spine have a similar structure to the vertebrae in the lumbar and thoracic regions with the exception of the uppermost cervical vertebrae. The Axis and the Atlas have a unique joint structure which allows for extra rotation of the head and neck. This, in turn, leads to an increased possibility of wear and tear and acute injury from trauma such as whiplash or contact sports injury. Adverse changes in posture also compromise the neck and can lead to chronic or acute neck pain, spinal degeneration, spinal stenosis, and compression of the spinal cord.
Spinal Cord Injury and Trauma
Extreme trauma to the neck, or chronic compression of the spinal cord from tumor growth or stenosis which remain unaddressed or untreatable, can lead to defects in spinal cord function. As the cervical spinal cord has the majority of nerve signals from and to the whole body passing through it, any dysfunction in this area can have enormous consequences for general health and mobility. Nerve damage and spinal cord dysfunction may lead to loss of sensation, poor reflex control, paralysis, muscle spasticity, and incontinence, amongst other things. Initial symptoms of cervical spinal cord compression may include radiculopathy in the upper limbs, muscle weakness, numbness, and tingling. Longer term consequences may include the atrophy of muscles through disuse, paralysis, and loss of sensation.
Cervical Spine Blood Vessels
Numerous blood vessels pass through the cervical spinal area, with some closely connected to the spinal column and responsible for delivering oxygenated blood to the spinal structures themselves. Similarly, waste material from general cell metabolism in the spine is taken away by venous circulation. Compression of the spine may impact these blood vessels and lead to dysfunctional circulation to the chest, arms, neck, head, and spine itself. Ischaemia can cause pain and atrophy of tissue, with further issues such as hyper- or hypomobility of the muscles which in turn increases the possibility of injury to the neck.
Muscles and Ligaments of the Cervical Spine
Many muscles support the neck and head and these are put under constant strain during our daily activities. Computer neck, text neck, tension headaches, neck stiffness, fibromyalgia, and even jaw pain are amongst the problems that can arise through excess strain on the muscles of the cervical spine. Those with fibromyalgia may have abnormal fatty tissue where these muscles should be, and this can lead to dysfunctional motor neurone firing resulting in spasms and pain. Ligaments in the cervical spine also act to support the vertebral column and the head on top of the neck, with these liable to become strained if posture is poor or if injury such as whiplash occurs.
Pharynx, Larynx, Trachea, and Thyroid
Other structures in the neck include the pharynx, larynx, thyroid, and trachea. These frequently share innervation from cervical spinal nerves and circulation from major blood vessels such as the inferior thyroid artery or carotid artery. If the health of the trigeminal nerve or other major nerves is affected by spinal compression or stenosis then numerous problems may arise in the correct function of these structures. Respiratory issues, difficulty swallowing, abnormal hormone responses, and changes to the voice are all potential difficulties occurring due to pathological changes in the cervical spine.
Pathology of the Cervical Spine
Cervical spinal anatomy is complex, which is one of the reasons that spinal surgery in this region can be difficult and contraindicated in many cases. Treating conditions of the cervical spine usually takes a conservative route unless there is acute potential for further damage which surgery may help prevent. Those suffering neck pain are usually able to rest and recuperate with no long-lasting trouble, but there is little room for manoeuvre in the cervical spine making even a small structural defect become a major issue.