Scalenus Posterior
origin: posterior tubercles of transverse processes of 4th, 5th, and 6th cervicals; insertion: lateral superior surfaces of 2nd rib behind attachment of Serratus Anterior; action: acting unilaterally, flexes and rotates cervical vertebrae; when acting bilaterally, flexes the neck and raises 2nd rib; nerve supply: posterior branches of C5 , C6 , C7, … Read more