BACKGROUND AND OBJECTIVE: The omohyoid muscle is one of the muscles among the infrahyoid muscles. Due to the connections and proximity of this muscle to the brachial plexus, carotid sheath, phrenic nerve and sternocleidomastoid muscle, it is very important to be aware of all possible variations of this muscle in terms of anatomic, clinical and surgical factors.
CASE REPORT: During the dissection of posterior carotid triangle on the left side of the neck of a 55-year-old male cadaver (who had been purchased about two years ago from Tehran University of Medical Sciences) for master's students of anatomy in the dissection room of Babol University of Medical Sciences, it was observed that instead of passing under the sternocleidomastoid muscle, the intermediate tendon of the omohyoid muscle passes through its two origins connected to the sternum and the clavicle.
CONCLUSION: This type of variation of the omohyoid muscle can be very important due to the proximity of this muscle to the surrounding elements and its effect on the large vessels of the carotid sheath and surrounding tissues.