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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,   C8 , lateral musclular  branch of C3, and C4;
synergists: Scalenus medius, Scalenus Anterior, Sternocleidomastoid, Longus Capitis, longus coli, suprahyoid, infrahyoid, and platysma