Os lenticularis

The os lenticularis (os lenticulare) is a minute accessory auditory ossicle located in the articulation between incus and stapes that extends rostrally and somewhat medially form the distal end of the incus.

When the connection between the incus and stapes ossified (in man, and occasionnaly in dogs), this connection forms the lenticular process.

Note : for some authors (like Barone), the os lenticularis is never present in mammiferes and always results from a broken lenticular process