The perpendicular plate of the ethmoid bone (vertical plate) is a thin, flattened lamina,

polygon In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed '' polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two ...

al in form, which descends from the under surface of the

cribriform plate In mammalian anatomy, the cribriform plate (Latin for lit. ''sieve-shaped''), horizontal lamina or lamina cribrosa is part of the ethmoid bone. It is received into the ethmoidal notch of the frontal bone and roofs in the nasal cavities. It supp ...

, and assists in forming the

septum of the nose The nasal septum () separates the left and right airways of the nasal cavity, dividing the two nostrils. It is depressed by the depressor septi nasi muscle. Structure The fleshy external end of the nasal septum is called the columella or col ...

; it is generally deflected a little to one or other side. The anterior border articulates with the spine of the frontal bone and the crest of the nasal bones. The posterior border articulates by its upper half with the

sphenoidal crest The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the o ...

, by its lower with the

vomer The vomer (; lat, vomer, lit=ploughshare) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right max ...

. The inferior border is thicker than the posterior, and serves for the attachment of the

septal nasal cartilage The septal nasal cartilage (cartilage of the septum or quadrangular cartilage) is composed of hyaline cartilage. It is somewhat quadrilateral in form, thicker at its margins than at its center, and completes the separation between the nasal cavit ...

of the nose. The surfaces of the plate are smooth, except above, where numerous grooves and canals are seen; these lead from the medial foramina on the cribriform plate and lodge filaments of the

olfactory nerves The olfactory nerve, also known as the first cranial nerve, cranial nerve I, or simply CN I, is a cranial nerve that contains sensory nerve fibers relating to the sense of smell. The afferent nerve fibers of the olfactory receptor neurons tr ...

Additional images

File:Slide2rome.JPG, Perpendicular plate of Ethmoid.

References

External links

* - "Diagram of skeleton of medial (septal) nasal wall." * - "Nasal septum, lateral view" * () Bones of the head and neck {{musculoskeletal-stub