Abstract
Many studies have been performed on the mimetic muscle and the facial nerve of adult humans. However, the morphological features of the mimetic muscle and the facial nerve in fetuses have not been elucidated. The aim of this study was to examine the mimetic muscle and the facial nerve in fetuses and to elucidate the features of the mimetic muscle and the facial nerve in newborns and infants. In this study 8 sides of 5 cadavers aged 23 to 36 weeks of gestation were investigated. Concerning the differentiation of the mimetic muscle, although the muscles, inserted around palpebral fissures and oral fissures, differentiated well, the muscles inserted around the nose and eyebrows differentiated poorly. Concerning the development of the facial nerve in each mimetic muscle, although the zygomatic, buccal, mandibular and cervical branches developed well, the temporal branch developed poorly. Therefore, the differentiation of the mimetic muscle and the development of the facial nerve correlate to each other ; the mimetic muscle and the facial nerve around palpebral fissures and oral fissures develop better than around the nose and the eyebrow.
