282  FACIAL  NEBYE  DC  THB  TBHPOBAL  BOITK.
222.  Pneumo-gtuiric  wtfnv.— This  nerve  leaves  the  cranium  in
company  with  the  nervus  accessorius>  through  a  canal  in  the  dura
mater  hehind  that  for  the  glosso-pharyngeal.  At  its  entrance  into
the  canal  it  is  composed  of  a  numher  of  separate  filaments ;  hut
the  filaments  very  soon  hecome  closely  aggregated  and  imhedded
in  a  small  ganglion.  This  ganglion,  first  described  by  Arnold,'*'  is
rather  round  in  form,  and  about  ^  of  an  inch  in  diameter.  It  is
connected  by  filaments  to  the  S3rmpathetic  and  to  the  petrous  gan-
glion of  the  glosso-phar3mgeal.  But  its  most  singular  branch  is
one  named  by  Arnold  "  the  auricular"  because  it  is  distributed  to
the  pinna  of  the  ear.  This  branch  enters  a  minute  foramen  in  the
jugular  fossa,  near  the  styloid  process,  and  then  proceeds  through
the  substance  of  the  bone  to  the  aqueductus  Fallopii,  where  it
divides  into  two  branches ;  one  joins  the  facial  nerve,  the  other
passes  to  the  outside  of  the  head  through  a  canal  between  the  front
of  the  mastoid  processs  and  the  meatus  auditorius,  and  is  distri-
buted to  the  back  of  the  cartilage  of  the  ear.
Immediately  below  this  its  first  ganglion  the  pneumo-gastric
nerve  is  joined  by  two  branches  from  the  nervus  accessorius,  and
consequently  becomes  afler  this  junction  a  compound  nerve. f
The  great  ganglion  of  this  nerve  at  the  base  of  the  skull  has
been  already  examined  (§91,  A.)


PISSFCTION  OF  THE   FACIAL   NERVE  THROUGH  THE   TEMPORAL

BONE.
