diff --git a/docs/yap.tex b/docs/yap.tex
index fd967d673..198f912cd 100644
--- a/docs/yap.tex
+++ b/docs/yap.tex
@@ -3900,7 +3900,10 @@ Integer bitwise negation.
 The greatest common divisor of the two integers @var{X} and @var{Y}.
 
 @item msb(@var{X})
-The most significant bit of the integer @var{X}.
+The most significant bit of the positive integer @var{X}.
+
+@item lsb(@var{X})
+The least significant bit of the positive integer @var{X}.
 
 @item [@var{X}]
 Evaluates to @var{X} for expression @var{X}. Useful because character