origin: posterior tubercles of the transverse process of 2nd to 7th cervical vertebrae;
insertion: superior surface of the 1st rib behind subclavian groove;
action: acting unilaterally, flexes and rotates cervical vertebrae; raises first rib; when acting bilaterally, flexes the neck;
nerve supply: posterior branches of anterior primary rami of C3, C4; lateral muscular branches C3, C4;
synergists: sternocleidmastoid, Scalenus Anterior & Scalenus Posterior, Longus Capitis, longus coli, suprahyoid, infrahyoid and the platysma
Original Text by Clifford R. Wheeless, III, MD.
Last updated by Data Trace Staff on Thursday, December 15, 2011 11:21 am