Anatomy of the transversus nuchae muscle and its relationship with the superficial musculoaponeurotic system.

[BACKGROUND] Previous studies have proved the existence of muscle fibers in the superficial musculoaponeurotic system (SMAS) of the parotid and masseter region; however, no studies have investigated the origination of the muscle fibers in the SMAS. Theoretically speaking, the muscle fibers within the SMAS in the parotid and masseter region might originate from a certain muscle with a definite origin and insertion. Based on this hypothesis, the authors' study investigated the origination of the muscle fibers in the SMAS of the parotid and masseter region to provide anatomical evidence that can improve our understanding of the SMAS.

[METHODS] An anatomical study was performed on 20 halves of seven fixed and three fresh adult cadavers (seven male and three female cadavers). A traditional bilateral face-lift incision was designed in each cadaver, and the muscle fibers within the SMAS in the parotid and masseter region, along with the origin and insertion, were investigated, dissected, analyzed, and photographed.

[RESULTS] The transversus nuchae muscle can be divided into two sections according to the origin of its tendons. The muscular fasciculi of the two sections run transversely across the sternocleidomastoid muscle, insert into the superficial fascia above the parotidomasseteric fascia, and terminate in the zygomatic region. The muscle fibers within the SMAS in the parotid and masseter region come from the transversus nuchae muscle.

[CONCLUSIONS] The authors' study first investigated the transversus nuchae muscle combined with the SMAS and clarified the issue that has been neglected by previous studies for more than 30 years. The authors hope this will unify their understanding of the SMAS and offer plastic surgeons and readers a brief insight into the SMAS.