Cervical  Enlargement. — We  are  chiefly  concerned  with  the  lower  brachial  part  of
this  region,  that  below  the  fourth  cervical.  The  upper  part  contains  centres  for  the  muscles
of  the  neck,  especially  for  the  sterno-mastoid  and  upper  part  of  the  trapezius.  The  diaphragm
is  probably  represented  in  the  gray  matter  at  -the  level  of  its  nerve  roots,  the  fourth  cervical.
In  the  brachial  region  of  the  cervical  enlargement,  the  muscles  of  the  shoulder  are  repre-
sented chiefly  in  the  upper  part ;  the  intrinsic  muscles  of  the  hand  in  the  lower  part.  The
flexors  of  the  elbow  are  represented  above  its  extensors ;  and  the  supinators  and  extensors  of
the  wrist  above  the  flexors  of  the  wrist.
Deltoid,  Scapular  Muscles,  Pectoralis,  and  Serratus. — Fifth  and  sixth  segments,  for  the  most
part  the  sixth,  and  probably  the  outer  group  of  nerve  cells.  The  centres  for  the  two  parts  of
the  pectoralis  are  separate,  and  are  associated — the  clavicular  with  that  of  the  serratus  mag-
nus,  the  costal  with  that  of  the  latissimus  dorsi  (see  p.  49).  These  associated  muscles  are
represented  near  together,  but  not  at  the  same  spot ;  the  association  is  often  present  in  dis-
ease of  the  anterior  cornu,  but  one  muscle  may  be  affected  without  that  which  is  commonly
associated  with  it.
The  Flexors  of  the  elbow  and  supinators  probably  correspond  nearly  in  level  with  the
deltoid.     The  whole  of  this  series  of  muscles  may  be  affected  alone   by  disease  of  the  nerve

*  Archiv  f.  Psychialrie,  vol.  ix.
