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Transverse myelitis
A guide for patients and carers
The spinal cord
The spinal cord carries messages from the brain to the body and from the body to the brain. It is made up of cells called neurons and surrounding support cells. Neurons have long extensions/projections called axons that carry the messages (electrical impulses) up and down the spinal cord. To increase the speed at which nerve messages travel, most axons are surrounded by an insulating material called myelin which is produced by specialised cells called oligodendrocytes.
You will find a diagram of the brain, spine and spinal cord in the printed bound booklet and the free downloadable pdf.
You will find a diagram of the brain, spine and spinal cord in the printed bound booklet and the free downloadable pdf.
Axons are arranged in bundles called tracts that are grouped together on the basis of what they do. Some are involved in motor function (i.e. they stimulate muscles to produce movement), while others carry sensory messages (i.e. touch, pain, position and vibration).
The symptoms of transverse myelitis depend on which tracts are damaged by the inflammation. For example the tracts that relay messages from the brain to the muscles run together in the front part of the spinal cord. The tracts that bring touch messages and messages about joint movement to the brain are found on the back of the spinal cord. Messages for pain and temperature travel in tracts on the side of the spinal cord as do messages between the bladder and the brain.
Within each tract, the axons carrying messages to and from a particular region of the body lie close to each other. Nerves from the arms join the spinal cord in the neck region and if there is damage to the spinal cord below this (as is usually the case in transverse myelitis), the legs but not the arms are affected. In other words, the effects of damage to the spinal cord are felt below the damaged area.
The symptoms of transverse myelitis depend on which tracts are damaged by the inflammation. For example the tracts that relay messages from the brain to the muscles run together in the front part of the spinal cord. The tracts that bring touch messages and messages about joint movement to the brain are found on the back of the spinal cord. Messages for pain and temperature travel in tracts on the side of the spinal cord as do messages between the bladder and the brain.
Within each tract, the axons carrying messages to and from a particular region of the body lie close to each other. Nerves from the arms join the spinal cord in the neck region and if there is damage to the spinal cord below this (as is usually the case in transverse myelitis), the legs but not the arms are affected. In other words, the effects of damage to the spinal cord are felt below the damaged area.
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