reversal lines

reversal lines,

n.pl stained scalloped microscopic lines caused by the resorption in bone and cementum.
References in periodicals archive ?
The second enabling factor is that, because it is not easy to produce pairs of reversal lines that mesh both grammatically and semantically with neighboring lines in two separated parts of a poem while at the same time accommodating rhyme and meter, the lines in rhyming palindromic verse are generally made to be grammatically and semantically self-contained.