Macroanatomic structure and morphometric analysis of middle ear in ostrich (Struthio camelus)

Ostrich (Struthio camelus) is a species belonging to the Struthionidae family of Struthioniformes order that does not have the flying ability among birds. The aim of this study was to make a subgross investigation on anatomical structures of middle ear in ostrich and to determine the morphometry of the columella. In the present study, 4 adult ostrich heads were used in the study. Tympanic cavity and the formations inside are removed from the skull by protecting the cranial roof. Subgross examinations of tympanic cavity, columella and other anatomic structures were then performed, and morphometric measurements of columella and some anatomical structures were performed using a digital calliper.It was determined that tympanic cavity, surrounded by ear capsule (os oticum), had a conical shape and was covered with mucosa that was tightly adjacent to the periosteum. Tympanic membrane, columella and osteochondral structures, ligaments, a branch of external ophthalmic artery and the presence of chorda tympani were detected in tympanic cavity. It was observed that columella was placed diagonally in tympanic cavity. The vestibular (proximal) end having a circular shape was found to have a large basis and annular ligament which ended up with thickened, small columns.