We consider the
space, CRp(M), consisting of CR functions which also lie in Lp(M) on a
quadric submanifold M of Cn of codimension at least one. For 1 ≤ p ≤∞, we
prove that each element in CRp(M) extends uniquely to an Hp function on
the interior of the convex hull of M. As part of the proof, we establish a
semi-global version of the CR approximation theorem of Baouendi and Treves for
submanifolds which are graphs and whose graphing functions have polynomial
growth.