The styloauricular muscle: clinical relevance and literature review of this rare muscle.

PURPOSE: In humans, the styloauricularis is a rare muscle extending from the tragal cartilage of the auricle to the styloid process. When it contracts, by bearing on the styloid process, it increases the cephalo-auricular angle. It can be a landmark for the facial nerve. We report a case with bilateral presence of the styloauricularis.

METHODS: Bilateral presence of the styloauricularis was discovered during routine dissection of the head and neck.

RESULTS: In the presented case, styloauricularis muscles arose from the cartilage of the external acoustic meatus on both sides of the head, crossing halfway along the facial nerve trunk and inserting the styloid process. Both muscles were vascularized by a branch of the posterior auricular artery, and innervated by the facial nerve.

CONCLUSIONS: The ventral auricular muscle, formed by the auricular parotid and the styloauricular muscles, is a muscle that lowers and abducts the auricle in animals. There is generally considered to be no equivalent for these muscles in humans, however, this bilateral case reveals evidence to the contrary. There is a dearth of scientific literature about the styloauricularis. The study of this muscle demonstrated the usefulness of comparative anatomy in understanding its action in increasing the cephalo-auricular angle.