  The ultrastructure fluctuations and complex dynamics of the multi-layered
membrane structure of myelin are fundamental for understanding and control its
formation process and its degeneration and repair in neurological diseases such
as multiple sclerosis (MS). Myelin is considered a liquid-crystal but
information are confined to its average structure due to limitations of the
available standard techniques. To overcome this limitation in this work we have
used Scanning micro X-ray Diffraction (S{\mu}XRD) which is a unique
non-invasive probe of both k-space and real space allowing to visualize
disorder in myelin with high spatial resolution in real space. We have used
this method to examine the myelin sheath in the sciatic nerve of Xenopus
laevis. Our results open could open new venues for understanding formation and
degradation of myelin.
