The medial surface of the labyrinth of ethmoid
consists of a thin lamella
, which descends from the under surface of the cribriform plate
, and ends below in a free, convoluted margin, the middle nasal concha
It is rough, and marked above by numerous grooves, directed nearly vertically downward from the cribriform plate; they lodge branches of the olfactory nerves, which are distributed to the mucous membrane covering the superior nasal concha.