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Next to neurenteric cysts,

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I find diastematomyelia as one of my favorite spinal lesions.

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This is,

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again a congenital lesion in which the spinal cord is

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separated into two components. These are hemicords,

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if you will, that are within one enlarged thecal sac,

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and these hemicords will recombine

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lower down in the lumbar region.

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The thing that separates the two halves of the cord

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is most commonly fibrous tissue.

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However,

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it can occasionally be secondary to bone in between the two

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hemicords. This is to be distinguished from diplomyelia.

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With diplomyelia,

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you have two separate spinal cords that are duplicated,

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and each of those spinal cords has two sets of

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nerve roots going to the right and to the left.

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With diastematomyelia , you have a split core.

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But each of the hemicords only has one side nerve roots.

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So the left side obviously would have the left nerve roots,

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and the right side would have the right nerve roots.

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Here is an MRI scan showing a patient who has

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diastematomyelia. When we look at these T1-weighted scans,

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we see that the cord appears to be split.

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And what is splitting it is something that has

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dark signal intensity on T1-weighted scan,

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as well as bright signal intensity

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on the T1-weighted scan.

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This is in point affect bone marrow

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fat as well as bone cortex,

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which is separating the two hemicords of this patient

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with diastematomyelia. As I mentioned, lower down,

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when the separation is no longer present,

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these two hemicords will recombine to a cord that looks a

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little bit bizarre because it's got a more narrow central

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portion here representing the two hemicords.

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However, it does recombine, and the patient does have

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intact nerve roots.

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You'll notice that on this T1-weighted scan, that we have nerve

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roots both anteriorly as well as posteriorly on both sides.

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Diastematomyelia may be associated

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with abnormalities with spina bifida,

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a syrinx in the spinal cord above the separation,

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and rarely will have myelomeningoceles,

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as well as Arnold-Chiari malformation associated with it.