In the standard routine for testing cranial nerve function following a cere
brovascular accident (CVA) compromising the corticonuclear supply to the cr
anial nerves, sternomastoid muscle ISM function is checked by means of head
rotation against resistance. SCM appears to be an exception to the general
ly contralateral motor weakness resulting from a CVA. The thrust of this ar
ticle is that appearances can be deceptive: SCM is more likely to be a post
ural stabilizer than a prime mover in head rotation. (C) 2001 Wiley-Liss. I
nc.