Objectives : The aim of this study is to review the gross anatomy and variations of the stapedius muscle and its relations to the structures forming the retrotympanic area. In ad­dition, this study will try to present a theory to explain the reason for these variations from a developmental point of view. ....-*.>
Subjects and Methods : Thirty-five temporal bones were dissected, and studied utilizing a microscope and otoendoscopes. The muscle gross anatomy and its relations were stud­ied. •..-.••. .",:_ - .". --. .•
Results : Marked variations in the origin and size of the muscle, the
course of its bony canal and its rela­tion to the facial nerve canal were de­tected. These were mainly influenced by the sinus tympani development. These variations affected the length of the tendon and the pyramidal emi­nence. The presence of ectopic mus­cle bundles was confirmed in one specimen.
Conclusion : The stapedius mus­cle anatomy can vary significantly from one temporal bone to another. In some situations, these variations can be of surgical importance worth enough to be recognized.