The Splenius Cervicis is a muscle located in the back of the neck. It is part of the splenius group, which also includes the Splenius Capitis. This muscle originates from the upper thoracic vertebrae and inserts into the cervical vertebrae, specifically the transverse processes of the second to fourth cervical vertebrae. Its primary function is to assist in the rotation and extension of the neck. When the Splenius Cervicis contracts, it helps turn the head to the side and supports the head's backward movement. This muscle plays a crucial role in maintaining proper posture and facilitating head movements, making it important for activities such as looking around and nodding.