Tympanic annulus

The tympanic annulus is the thickened edge of the pars tensa of the tympanic membrane, anchoring it in the tympanic sulcus .

Gross anatomy

The tympanic annulus is formed by a fibrocartilaginous thickening of the edge of the pars tensa and has a horseshoe-shaped configuration. It is deficient superiorly at the notch of Rivinus, where the pars flaccida is found . The tympanic annulus inserts into the tympanic sulcus, a shallow groove of the external acoustic canal (EAC), attaching the tympanic membrane to the EAC. The annulus has a triangular cross-section with the base inserted into the sulcus and the apex pointing towards the tympanic membrane .

History and etymology

The notch of Rivinus was first described by Augustus Quirinus Rivinus (1652–1723), a German anatomist .