The posterior scalene is one of the three scalene muscles located in the neck. It is situated at the back of the neck, alongside the anterior and middle scalene muscles. This muscle originates from the cervical vertebrae and attaches to the second rib, playing a role in elevating the rib during breathing and assisting with neck movement. The posterior scalene is innervated by the cervical spinal nerves and is involved in the overall function of the neck and upper respiratory system. It is important for maintaining proper posture and can be affected by conditions such as cervical radiculopathy or muscle strain.