The scalenus anterior muscle elevates the first rib and is also used to flex and bend the neck. The muscle starts at the anterior tubercles of 3rd cervical vertebrae and runs down through to the 6th cervical vertebrae before attaching to the scalene tubercle on the first rib. It is located between the subclavian artery and the subclavian vein, with the phrenic nerve crossing over this muscle's anterior surface. The phrenic nervice is the only motor innervation to the body's diaphragm. The scalenus anterior muscle is an important landmark in the neck and is used to reference the supraclavicular triangle. The subclavian vein and the subclavian artery is also in this same area. The subclavian artery is posterior to the scalenus anterior and the subclavian vein lies anterior to the scalenus anterior muscle. The scalenus anterior muscle is a muscle of inspiration. Its primary job is to rotate and flex the cervicals unilaterally as well as to raise the first rib. When the muscle is moving bilaterally, it flexes the neck.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Scalenus anterior