The spine is the frame of the body. Its alignment affects all the organs and vessels that surround or are attached to it, including the brain and its blood vessels. The spine also houses the cord, as well as its blood vessels and cerebrospinal fluid (CSF) pathways.
This post is about the impact of scoliosis on the contents of the posterior fossa of the skull, which includes the drainage system of the brain. Abnormal curvatures in the spine alter the normal alignment and relationship of the head and spine, and as a result, the normal relationship of the brain and cord. Curvatures also alter their circulatory routes.
While there may be an attachment of the covering of the upper cord to the foramen magnum, for the most part, the brain is unattached and floats freely inside compartments within the cranial vault. Similarly, the spinal cord is unattached and moves fairly freely inside the spinal canal to accommodate movement of the spine. The end of the spinal cord, called the filum terminale, attaches to the tail end of the spine, called the coccyx. Certain movements of the spine, such as flexion stretch and strain the cord somewhat. Abnormal curvatures of the spine stretch and strain the spine that much more and thus deform the cord and brainstem.
Scoliosis is an abnormal sidewards curvature of the spine. It is typically thought of as a childhood condition but adults can get scoliosis as well. A thoracolumbar scoliosis affects the thoracic and lumbar spines. The thoracic spine is attached to the ribcage. The lumbar spine is the low back.
A double major scoliosis starts in the low back and pelvis and bends one way and then reverses itself and bends the other way in the thoracic spine. The thought is the second curve is to help balance the head on the spine. This may not be the case all the time. The x-ray above is of a young female not quite seventeen. It is a perfect example of a double major scoliosis. The x-ray was contributed to Wikimedia by the University of Utah Hospital Department of Radiology from a case in 2009.
In most cases the cause of childhood scoliosis is unknown but it affects females far more than it does males. In this regard there is also a connection of scoliosis to tethered cord syndromes. In tethered cord the spinal cord is genetically too short for the length of the spine. This creates a strain putting tension on the cord, which causes a downward traction on the brainstem.
Compared to males, females finish developing neurologically much earlier than males. The body, however, can continue to grow and outgrow the length of the cord. It makes sense that the normal growth of the spine could be restrained by the tension caused by the cord thus resulting in a scoliosis. This could explain why tall females seem to be somewhat more susceptible to scoliosis.
In addition to tethered cords, scoliosis can also alter the normal position of the brain within the cranial vault. Tethered cords for example pull the brain down toward the foramen magnum and base of the skull. Head tilts and twists due to scoliosis, likewise, alter the normal alignment of the brain on top of the spine and inside the cranial vault. It is not surprising then, that scoliosis is also associated with Chiari malformations in which the cerebellum is dislocated to a position out of the posterior fossa and into the foramen magnum.
Adults can acquire scoliosis later in life due to injuries and degeneration of the spine such as from arthritis or osteoporosis. Parkinson’s disease also affects the normal alignment of the spine causing it to bend forward into flexion. Rheumatoid arthritis can cause severe destruction of the spine and subsequent scoliosis. Tethered cords can also be caused in adults by injuries and scar tissue inside the spinal canal that restrict the normal movement of the cord.
In addition to scoliosis, kyphosis is an abnormal backwards curve in the spine. Parkinson’s disease and osteoporosis can cause kyphosis. Some people are born with a kyphosis. Kyphosis of the cervical spine can occur as a result of whiplash injuries. Kyphosis, like scoliosis, alters the normal course of blood vessels. It can also create tension in the cord similar to scoliosis when it tethers the cord.
In addition to Chiari malformations and tethered cords, scoliosis and kyphosis alter the normal course of blood vessels and cerebrospinal fluid (CSF) pathways and can thus affect blood and CSF flow. Scoliosis and kyphosis most likely play a significant role in chronic cerebrospinal venous insufficiency, better known as CCSVI. It’s another topic I will cover in the future.
To get a better picture of the potential impact of scoliosis, Chiari malformation, and tethered cord on the brainstem and cerebellum in the posterior fossa click on the following link http://www.upright-health.com/posterior-fossa-chiari.html .