The anterior and middle scalene muscles lift the first rib and bend the neck to the side they are on.

It arises from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebrae, and descending, almost vertically, is inserted by a narrow, flat tendon into the scalene tubercle on the inner border of the first rib, and into the ridge on the upper surface of the second rib in front of the subclavian groove.

The middle scalene arises from the posterior tubercles of the transverse processes of the lower six cervical vertebrae.

It descends along the side of the vertebral column to insert by a broad attachment into the upper surface of the first rib, posterior to the subclavian groove.

[2] The anterior and middle scalene muscles lift the first rib and bend the neck to the same side as the acting muscle;[3] the posterior scalene lifts the second rib and tilts the neck to the same side.

[7] The muscles are named from Greek σκαληνός (skalēnós), meaning 'uneven'[8] as the pairs are all of differing length.