The =palatine bones= (Ossa palatina) are situated on either side of the
posterior nares, and form the posterior margin of the hard palate. Each
is twisted so as to form a horizontal and a perpendicular part.
The =horizontal part= (Pars horizontalis) is a narrow plate which forms
the posterior part of the hard palate. It presents smooth =nasal= and
=palatine surfaces=. The =internal border= meets its fellow at the
median palatine suture, on the nasal aspect of which is the nasal crest.
The =anterior border= joins the palate process of the maxilla at the
transverse palatine suture, and forms with it the anterior palatine
foramen. The =posterior border= is concave and free; it gives attachment
to the aponeurosis of the soft palate.
The =perpendicular part= (Pars perpendicularis) is more extensive and
forms the outer boundary of the posterior nares. The =nasal= or
=internal surface= is in the greater part of its extent concave and
smooth; it is marked by a narrow rough area to which the pterygoid bone
is attached. Below this the bone curves outward, forming the pterygoid
process. The =maxillary= or =external surface= (Facies maxillaris)
presents three areas for consideration. The largest articulates with the
maxilla; it is rough and is crossed by a groove which enters into the
formation of the palatine canal. Behind this is a smooth part which
assists in forming the =pterygo-palatine fossa=. The rough area below
this is overlapped by the pterygoid process of the sphenoid bone. The
=superior border= is perforated by the =sphenopalatine foramen=. Behind
the foramen the two plates of the bone separate to inclose part of the
=sphenopalatine sinus=. The inner plate curves inward to articulate with
the vomer. The outer plate joins the maxilla and frontal and the orbital
wing of the sphenoid.
=Development.=—The palatine bone ossifies in membrane from a single
center.