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.
