The aim of this study was to elucidate the precise anatomy of the zygomaticomandibularis muscle through cadaveric dissection and magnetic resonance imaging (MRI). Five fresh human cadavers and 10 fixed cadavers were dissected. Nine preserved human cadavers were used for the MRI study. Four volunteers took MRIs of their head as well. Zygomaticomandibularis muscle was found in all the cadaveric specimens. It is a fan shaped muscle. The length of the muscle is 25.1 ± 4.6 mm, and the width at the zygomatic arch is 16.6 ± 4.2 mm. The thickness is approximately 4.8 ± 1.9 mm. It originates from the deep layer of the deep temporal fascia approximately 1 cm above the zygomatic arch and is inserted into the superior border and outer surface of the mandible between the coronoid process and mandibular notch. The deepest layer of the masseter muscle covers the lateral surface of zygomaticomandibularis. We believe that this muscle functions as coordinator of the temporalis and masseter in mammals with strong masticatory power but is a degraded or rudimentary muscle in humans.
From the *Department of Plastic Surgery, Inha University Hospital, Incheon, Korea, the †Department of Radiology, Sungkyunkwan University School of Medicine, Gyunggi, Korea, the ‡Dongyang Aesthetic Plastic Surgical Clinic, Seoul, Korea, and the §Department of Anatomy and BK 21 Project for Medical Science, College of Medicine, Yonsei University, Seoul, Korea.
Address correspondence to Hwang Kun, Department of Plastic Surgery, College of Medicine, Inha University. 7-206 Sinheung-dong, Jung-gu, Incheon, 400-711, Korea; E-mail: firstname.lastname@example.org
This work was supported by grant (R01-2005-000-10018-0) from KOSEF.