RT Book, Section
A1 Berkowitz, Aaron L.
SR Print(0)
ID 1174549355
T1 Motor Neuron Disease
T2 Clinical Neurology and Neuroanatomy: A Localization-Based Approach
YR 2016
FD 2016
PB McGraw-Hill Education
PP New York, NY
SN 9781259834400
LK accessmedicine.mhmedical.com/content.aspx?aid=1174549355
RD 2024/04/19
AB This  chapter  discusses  a  group  of  diseases  that  affect  motor  neurons  in  isolation,  collectively  referred  to  as  motor  neuron  disease.  Motor  neuron  disease  can  affect  upper  motor  neurons  (motor  neurons  of  the  central  nervous  system),  lower  motor  neurons  (motor  neurons  of  the  peripheral  nervous  system),  or  both  (Table  28–1).  The  primary  symptom  of  motor  neuron  disease  is  weakness.  The  distribution  of  weakness,  associated  signs  (upper  motor  neuron  vs  lower  motor  neuron  vs  both;  see  “Upper  Motor  Neuron  Lesions  Versus  Lower  Motor  Neuron  Lesions”  in  Ch.  4),  and  pace  of  progression  differ  depending  on  the  disease.  Just  as  there  are  upper  and  lower  motor  neurons  for  the  muscles  of  the  extremities,  the  motor  cranial  nerves  contain  lower  motor  neurons  under  the  control  of  upper  motor  neuron  cortical  input  (corticobulbar  tract).  The  muscles  of  the  face,  larynx,  and  pharynx  (bulbar  muscles)  are  affected  in  many  motor  neuron  diseases.