[2] The cells are located within the lateral mass (labyrinth) of each ethmoid bone and are variable in both size and number.

[5] The ethmoidal labyrinth is divided by multiple obliquely oriented, parallel lamellae.

The basal lamella is continuous medially with the bony middle nasal concha.

[9] Onodi cells are clinically significant because they lie in close proximity to the optic nerve and internal carotid artery, so surgeons should be aware of their existence when performing surgery on the sphenoid sinus so as not to damage these important structures.

[11] This article incorporates text in the public domain from page 154 of the 20th edition of Gray's Anatomy (1918)