My Spine - Lumbar
The cyst is filled with synovial fluid that is usually found in the joint space
for lubrication. These are completely benign (harmless) lesions and should
not be confused with cancerous lesions. They can, however, cause nerve com-
pression and foraminal stenosis.
Tarlov cyst – This cyst is filled with spinal fluid and develop in the mem-
brane that covers the nerve roots. If it is large, it can cause nerve compression
and pain. Surgery for this benign lesion can be difficult. The diagnosis is
made based on the fact that the cyst is in direct contact with a nerve root.
Arachnoid cyst – This is also a benign lesion and is formed from the inner
layer of the covering of the spinal cord. It is usually asymptomatic and will
only require surgery if it is very large and is causing symptoms secondary to
nerve compression.
Cauda Equina – This term is Latin for horse’s (Equina) tail (Cauda). It
describes the nerve roots that dangle down from where the spinal cord ends
and looks like a horse's tail. The spinal cord ends at approximately the level
of the first lumbar vertebra. When these nerve roots become compressed the
resulting syndrome of pain, weakness and paraesthesia (pins and needles) in
the legs with associated bladder and bowel dysfunction is called Cauda
Equina syndrome. This is a spinal emergency and requires immediate surgery.
Conus Medullaris (Conus) – This is the name given to the end of the spinal
cord. It has a tapered conical shape and the nerve roots of the Cauda Equina
exit from here. It is usually at the level of the first lumbar vertebra.
Filum Terminale (Filum) – This is the continuation of the conus medullaris
and is the thin cord-like structure that extends down to the end of the spinal
canal.
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