The peripheral nerves and muscles can get affected by a whole range of conditions.  Again I would refer the reader to specific texts or to raise questions of myself within instruction so that much more extensive explanation can be given.


The peripheral nerves as a whole however may be damaged by such conditions as diabetes and excess alcohol intake.  There are also a number of inflammatory conditions.  Nerves may also be damaged by injury or inadvertently damage during anaesthesia or surgery. 


Muscles tend to get damaged by either metabolic processes such as thyroid disease or by inflammatory diseases.  Unfortunately they may also be damaged as part of a range of congenital or genetic disorders as in fact can be most of the nervous system.


There are vast texts written about each group of disorders and even isolated rare conditions.