  It is argued that constituent quarks live in an effective theory that
possesses an approximate conformal invariance. An effective lagrangian is
constructed which in the large-$\nc$ approximation incorporates Regge
asymptotic constraints. The resulting picture explains why linear-sigma models
provide successful constituent quark descriptions, both at zero and finite
temperature. Our analysis suggests an interesting relation between non-linearly
realized conformal invariance and the completion of chiral multiplets in the
broken symmetry phase.
