﻿art. 
  27 
  ASYMMETRY 
  IN 
  SKULLS 
  OF 
  MAMMALS 
  HOWELL 
  5 
  

  

  Inquiring 
  more 
  fully 
  into 
  the 
  pathological 
  situations 
  present 
  it 
  is 
  

   found 
  that 
  — 
  

  

  (a) 
  The 
  right 
  mastoid 
  is 
  unusual 
  only 
  in 
  being 
  shortened 
  laterally 
  

   and 
  in 
  having 
  a 
  marked 
  process 
  inferiorly. 
  The 
  lateral 
  shortening 
  

   of 
  the 
  whole 
  right 
  side 
  of 
  the 
  occipital 
  is 
  probably 
  because 
  of 
  injury 
  

   to, 
  and 
  subsequent 
  abnormal 
  development 
  of, 
  the 
  muscles 
  originating 
  

   upon 
  the 
  infero-lateral 
  part 
  of 
  its 
  surface. 
  

  

  (b) 
  The 
  deformity 
  of 
  the 
  petrous 
  portion 
  of 
  the 
  temporal 
  is 
  not 
  

   marked, 
  aside 
  from 
  its 
  misplacement. 
  Its 
  chief 
  point 
  of 
  interest 
  lies 
  

   in 
  the 
  fact 
  that 
  there 
  is 
  almost 
  complete 
  closure 
  of 
  the 
  jugular 
  fora- 
  

   men 
  and 
  obliteration 
  of 
  its 
  fossa, 
  probably 
  through 
  the 
  healing 
  of 
  a 
  

   small, 
  diseased 
  portion 
  of 
  both 
  the 
  petrous 
  and 
  occipital 
  margins 
  of 
  

   the 
  foramen. 
  The 
  occipital 
  was, 
  perhaps, 
  chiefly 
  instrumental, 
  for 
  

   its 
  border 
  has 
  extended 
  farther 
  forward 
  than 
  normal, 
  and 
  the 
  pet- 
  

   rous 
  is 
  correspondingly 
  displaced. 
  It 
  is, 
  of 
  course, 
  impossible 
  that 
  

   the 
  jugular 
  vein 
  was 
  suddenly 
  severed, 
  else 
  the 
  animal 
  had 
  died 
  at 
  

   once. 
  Rather 
  was 
  its 
  gradual 
  atrophy 
  brought 
  about, 
  enabling 
  

   other 
  veins 
  to 
  care 
  for 
  the 
  venous 
  blood 
  that 
  is 
  normally 
  carried 
  by 
  

   the 
  right 
  jugular. 
  The 
  functional 
  alteration 
  has 
  not, 
  however, 
  re- 
  

   sulted 
  in 
  any 
  increase 
  in 
  the 
  size 
  of 
  the 
  left 
  jugular 
  foramen, 
  for 
  the 
  

   latter 
  is, 
  in 
  fact, 
  smaller 
  than 
  seems 
  to 
  be 
  usual 
  in 
  this 
  genus. 
  

  

  (c) 
  The 
  condition 
  of 
  the 
  right 
  auditory 
  meatus 
  indicates 
  much 
  

   damage 
  to 
  the 
  inner 
  ear, 
  very 
  possibly 
  causing 
  complete 
  deafness 
  

   upon 
  that 
  side, 
  induced 
  by 
  severe 
  suppuration 
  of 
  the 
  parts. 
  The 
  

   passage 
  is 
  greatly 
  enlarged, 
  both 
  superiorly 
  and 
  inferiorly, 
  being 
  

   about 
  13 
  mm. 
  in 
  diameter, 
  as 
  against 
  7 
  for 
  this 
  measurement 
  of 
  the 
  

   left 
  passage. 
  The 
  lateral 
  length 
  of 
  the 
  inferior 
  border 
  of 
  the 
  meatus, 
  

   measured 
  from 
  the 
  carotid 
  foramen, 
  is 
  about 
  18 
  mm. 
  shorter 
  upon 
  

   the 
  right 
  than 
  the 
  left 
  side. 
  This 
  was 
  evidently 
  brought 
  about 
  by 
  

   suppuration 
  and 
  partial 
  absorption 
  of 
  the 
  bony 
  lining 
  of 
  the 
  meatus, 
  

   with 
  subsequent 
  healing 
  and 
  growth 
  of 
  new 
  bony 
  tissue 
  only 
  upon 
  

   its 
  outer 
  or 
  inferior 
  face. 
  

  

  (d) 
  The 
  right 
  glenoid 
  fossa 
  proper 
  is 
  not 
  greatly 
  altered, 
  but 
  the 
  

   eminentia 
  articularis, 
  anteriorly 
  adjoining, 
  is 
  flattened 
  and 
  much 
  

   pitted. 
  The 
  same 
  condition 
  of 
  pitting 
  obtains 
  upon 
  the 
  squamous 
  

   eminence 
  adjoining 
  the 
  process 
  of 
  the 
  tensor 
  palati. 
  The 
  conditions 
  

   to 
  be 
  observed 
  in 
  the 
  glenoid 
  region 
  are 
  naturally 
  correlated 
  with 
  

   the 
  following: 
  

  

  (e) 
  The 
  right 
  articular 
  surface 
  of 
  the 
  mandibular 
  condyle 
  is 
  flat- 
  

   tened, 
  broadened 
  in 
  an 
  antero-posterior 
  direction, 
  and 
  much 
  pitted 
  

   and 
  roughened, 
  and 
  the 
  neck, 
  as 
  measured 
  from 
  the 
  base 
  of 
  the 
  

   coronoid 
  process, 
  shortened 
  by 
  about 
  7 
  mm. 
  It 
  is 
  very 
  likely 
  that 
  

   the 
  functions 
  of 
  the 
  abnormal 
  side 
  of 
  the 
  jaw 
  were 
  even 
  more 
  se- 
  

   verely 
  interfered 
  with 
  than 
  can 
  now 
  be 
  told 
  from 
  an 
  examination 
  of 
  

   the 
  skull, 
  through 
  destruction 
  of 
  part 
  of 
  the 
  condyloid 
  ligaments. 
  

  

  