just in case there is a 1 in 10000 chance the needle can hit a small arteriole or veinThen why the need to teach aspiration during IM injections?
the real danger is local infiltration of lidocaine . in large enough dose and administered intravenously it is cardiotoxic
which unfortunately did happen in the SAF ward many many years ago. some young MO go and push a walloping dose into a large vein while trying to excise a lipoma and the poor patient went into arrhythmia and died
that's why we aspirate . in my business anything can happen . however remote.