Introduction:Anatomical variations of the neck muscles have previously been reported, involving in particular the omohyoid and sternothyroid muscles. We herein report a novel variant neck muscle found during a routine surgical procedure.Case Report:A 63-year-old women underwent a pelvi-mandibulectomy with bilateral neck dissection for a squamous cell carcinoma of the floor of mouth pT3N1. On the right neck dissection, the present peculiar muscle was discovered. It was located in the lateral region of the neck, deeply to the sternocleidomastoid muscle and caudally to the hyoid bone. It took origin from the sixth cervical vertebrae’s transverse process and attached caudally to the middle third of the clavicular bone, after having passed superficially to the omohyoid muscle’s intermediate tendon.Conclusions:Neck muscles are important during head and neck surgery due to their significance as surgical landmarks and their relationship with noble vessels. Being aware of possible variant that can alter classical anatomical reference points is important to prevent iatrogenic trauma.