CutaTieO'jphalangeal  Ligaments, — Strong  ligamentous  fibres,
first  described  I  believe  by  Professor  Cleland,  extend  from  the
sides  of  the  phalanges  near  their  articulations  and  are  inserted
into  the  skin  about  the  joints,  more  especially  into  the  thicker
and  wrinkled  skin  of  their  dorsal  aspect  These  ligaments
retain  in  its  place  the  integument  at  the  back  and  sides  of  the
joints  during  flexion.  They  are  present  about  the  joints  of  the
thumb  as  well  as  of  the  fingers.  Though  seen  at  the  distal
joints,  they  are  best  developed  at  the  first  inter-phalangeal
articulations  of  the  fingers.  The  fibres  are  attached  to  the
lateral  ridges  of  both  the  phalanges  of  a  joint  and  decussate —
some  passing  upwards  and  others  downwards — as  they  proceed,
behind  the  digital  artery  and  nerve,  before  spreading  out  into
the  skin  on  both  palmar  and  dorsal  aspects.
The  SYNOVIAL  MEMBRANE  of  each  of  these  joints  is  ample  and
loose,  and  extends  upwards  a  little  way  along  the  shaft  of  the
proximal  bone.  It  is  very  thinly  covered  above  the  upper
margin  of  the  fibro-cartQaginous  plate.
The  Arteries. — Blood  is  freely  supplied  to  these  joints  by
little  vessels,  which  after  coming  off  from  the  digital  arteries  run
along  in  the  sheaths  of  the  tendons,  one  on  each  side.  These
little  vessels  anastomose  beneath  the  tendons  at  both  ends  of
each  phalanx,  and  send  branches  through  the  fibrous  tissue  to
the  synovial  lining  of  the  joint.  These  vessels  are  very  constant
and  uniform  in  their  arrangement  and  distribution.
The  Nerves  are  supplied  from  the  digital  branches  of  the
corresponding  fingers.
