Peripheral hypermyelination Myelin tomacula Tomacula The presence of multiple sausage-shaped swellings of the myelin sheath (The Latin tomaculum means sausage). Several mechanisms that may lead to the formation of a tomaculum-for example, hypermyelination, redundant loop formation, the presence of a second mesaxon, transnodal myelination, two Schwann cells forming one myelin sheath, and disruption of the myelin sheath. Sural nerve biopsies typically show regions of myelin thickening as well as features of demyelination and remyelination. UMLS:C4020904