Extrathecal

Antimyelin antibodies are produced in an extrathecal site, as occurs in Sydenham's chorea.

These clinical and imaging features are highly suggestive of CSF leak in a patient with SIH syndrome, but more definitive diagnosis is achieved with demonstration of extrathecal CSF collections on spinal imaging (Fig. 10.13).

Numerous extrathecal developments have been recognized in graptolites, and are here discussed in relation to their position on the colony and the precise development.