Probably most significantly, several on the nerves that originate in the cervical spine control the diaphragm,  The anterior triangle on the neck is created by the anterior border from the sternocleidomastoid muscle, the inferior border of your mandible plus the midline in the neck. This triangle could be even further https://www.theorthopaedicandpainpractice.com/treatment-for-neck-pain-headaches/