What are the two bones that make up the posterior nasal septum?

The nasal septum is the internal part of the nose that
separates the left and right airways.  There are five structures that compose the nasal
septum:

1.    perpendicular plate of ethmoid bone
2.   
vomer bone
3.    cartilage of the septum
4.    crest of the
maxillary bone
5.    crest of the palatine bone

The two
structures at the posterior of the nasal septum are the perpendicular plate of ethmoid
bone, and the vomer bone.  Both of these bones contribute to forming the nasal septum. 
Both of these bones have small furrows for blood vessels, and grooves for
nerves.