The term tomaculous neuropathy
is derived from the Latin tomaculum signifying sausage and usually called hereditary neuropathy with liability to pressure palsy, or HNPP. It is a rare hereditary genetic disease affecting the nerves. On examination, the myelin coating around the nerves is much thicker than usual, giving them a sausage-like appearance, hence the term 'tomaculous'. Myelin is a fatty sheath that protects nerve fibers and accelerates the nerve's transfer of information. HNPP neuropathy has symptoms of pins and needles, or numbness or paralysis of varying length in one area of the body, in particular in the arms or legs.