1. A layer of myelin encasing (and insulating) the axons of medullated nerve fibers
   - myelin sheath

Derived forms: medullary sheaths

Type of: case, sheath

Part of: medullated nerve fiber [US], medullated nerve fibre [Brit, Cdn], myelinated nerve fiber [US], myelinated nerve fibre [Brit, Cdn]

Encyclopedia: Medullary sheath

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