1) Case 2) Neurilemma 3) Sheath 1) Neurilemma 
Neurolemma (also known as neurilemma or sheath of Schwann (Schwann`s Sheath)) is the outermost nucleated cytoplasmic layer of Schwann cells that surrounds the axon of the neuron. It forms the outermost layer of the nerve fiber in the peripheral nervous system. The neurolemma is underlain by the basal lamina (referred to as the medullary sheath in....
Synonym: neurilemma. ... Origin: neuro-+ G. Lemma, husk ... (05 Mar 2000) ... 
(noor″o-lem´ә) neurilemma.
Type: Term Pronunciation: nū′rō-lem′ă Synonyms: neurilemma
The neurolemma or neurilemma is the thin membrane that forms a sheath around nerve fibres.
[n] - thin membranous sheath around a nerve fiber
neurilemma noun thin membranous sheath around a nerve fiber
Greek neuron = nerve, and lemma = peel or rind; hence, the covering layer of a nerve.