2 types of hair cells – type 1 & type 2 – are present in the maculae.
Type 1 hair cells in the vestibule (saccule and utricle) are damaged by vestibulotoxic drugs like Streptomycin, Gentamicin, Tobramycin.
3 semicircular canals are present arranged at 90 degrees to each other – superior/anterior, horizontal/lateral and posterior.
Each semicircular canal has an ampullated (dilated) and non-ampullated ends.
The 2 non-ampullated ends of posterior and superior semicircular canals fuse to form the crus commune.
All the semicircular canals open into utricle only with their 5 openings (3 ampullated and 2 non-ampullated).
These semicircular canals sense the angular movement.
The structural and functional unit sensing these movements are called as cristae, present in ampullated end of each semicircular canal. A gelatinous cupula lies over crista.
Any abnormality of these maculae and cristae will cause vertigo.