TY  - CHAP
M1  - Book, Section
TI  - Vasculature of the Central Nervous System and the Cerebrospinal Fluid
A1  - Martin, John H.
PY  - 2016
T2  - Neuroanatomy Text and Atlas, 4e
AB  - CLINICAL  CASE  |  Middle  Cerebral  Artery  Occlusion,  Right  Side  Paralysis,  and  Global  AphasiaA  57-year-old  male  was  brought  to  the  emergency  room  after  being  discovered  by  his  wife  to  be  unable  to  move  his  right  arm  or  leg.  On  testing,  his  right  upper  limb  strength  was  0/5  and  the  lower  limb,  1/5.  The  left  limbs  had  normal  strength  and  spontaneous  movements.  In  addition,  there  was  drooping  of  the  right  side  of  the  lower  face.  Pinch  of  the  nail  beds—a  mildly  noxious  stimulus  that  elicits  a  withdrawal—revealed  withdrawal  of  the  left  arm  but  no  response  for  the  right  arm.  The  patient  was  able  to  look  to  the  left  but  not  the  right;  there  were  no  saccadic  (rapid,  conjugate)  eye  movements  to  the  right.  The  patient  was  unable  to  speak  and  only  followed  simple  commands.Figure  3–1A  shows  a  horizontal  MRI.  The  large  white  territory  corresponds  to  the  infarcted  region  on  the  left  side  of  the  cerebral  hemisphere.  Figure  3–18B  is  a  magnetic  resonance  angiogram  (MRA),  showing  the  distribution  of  arteries  with  flowing  blood.  Note  the  asymmetry  in  the  MRA,  with  an  absence  of  middle  cerebral  artery  perfusion  on  the  left  side.Answer  the  following  questions  based  on  your  readings  of  the  case  report  and  this  chapter.1.  The  patient's  lesion  is  large.  Occlusion  of  which  cerebral  artery  produced  the  lesion,  and  what  was  the  contribution  of  its  deep  and  superficial  branches?2.  Damage  to  what  single  key  structure  could  produce  the  major  limb  and  facial  motor  signs?Key  neurological  signs  and  corresponding  damaged  brain  structuresParalyzed  right  arm  and  legThe  corticospinal  tract,  which  is  key  to  controlling  the  contralateral  arm  and  leg,  descends  subcortically  and  then  travels  in  the  posterior  limb  of  the  internal  capsule  (see  Figure  2–17).  This  subcortical  white  matter  and  the  more  dorsal  parts  of  the  posterior  limb  of  the  internal  capsule  are  supplied  by  deep  branches  of  the  middle  cerebral  artery.  The  infarction  also  would  have  destroyed  part  of  the  lateral  precentral  gyrus,  where  the  corticospinal  tract  to  the  arm  segments  of  the  spinal  cord  originates.  This  is  supplied  by  superficial  branches  of  the  middle  cerebral  artery.  By  contrast,  the  infarction  spares  the  leg  area  of  motor  cortex  (see  Figure  10–8).  Whereas  the  descending  axons  are  destroyed  when  they  are  in  the  internal  capsule,  as  we  shall  see  in  later  chapters  sparing  of  the  cortex  may  help  during  neurorehabilitation.Right  lower  facial  droopThe  corticobulbar  tract  controls  facial  muscles.  This  is  the  component  of  the  descending  cortical  motor  pathway  that  controls  cranial  motor  nuclei  in  the  brain  stem.  (Bulb  is  an  archaic  term  to  describe  the  lower  brain  stem.)  The  tract  travels  subcortically  from  lateral  part  of  the  precentral  gyrus  (face  area  of  motor  cortex)  to  the  genu  and  posterior  limb  of  the  internal  capsule,  rostral  to  the  corticospinal  tract  axons.  The  subcortical  white  matter  and  dorsal  parts  of  the  internal  capsule  are  largely  supplied  by  the  deep  branches  of  the  middle  cerebral  artery.  The  face-controlling  area  of  motor  cortex  is  supplied  by  superficial  branches  of  the  middle  cerebral  artery.  Interestingly,  control  of  the  lower  face—like  that  of  ...
SN  - 
PB  - McGraw-Hill Medical
CY  - New York, NY
Y2  - 2024/04/19
UR  - neurology.mhmedical.com/content.aspx?aid=1129848941
ER  -