Anatomical characteristics of middle ear bones in rat

The aim of this study was to determine the anatomical features of the auditory ossicles in rat. Twenty temporal bones from 10 adult rats were used. The features of the ossicles were assessed with an ocular micrometer and photographed by a stereomicroscope. Finally, all data were evaluated and analysed using the Sigma Statt software. Temporal bone in rat was similar to other animals consists of three parts; squamous, tympanic and petrous. Tympanic bulla was cone shaped and its base was adjacent acoustic meatus caudolaterally. Average tympanic bulla height and length of the ear canal were 8 mm and 1 -1.5 mm respectively. The auditory ossicles were three bones: the malleus, the incus, and the stapes. The lenticular bone was a distinct bone, articulated with the tip of the long crus of incus. Morphometrical rtesults showed that the malleus was 3.34 ± 0.03mm in total length. In addition to head and handle, the malleus had three distinct processes; lateral, anterior and muscular. The incus had a total length 1.18 ± 0.04mm. It had long and short crura although the long crus developed better than short crus. The stapes had a total length 0.79 ± 0.03mm. It had a stapedial base with anterior and posterior crura. The length of anterior crus was more than posterior.