  The masses of the $D^\ast_{s0}(2317)$ and $D_{s1}(2460)$ resonances lie below
the $DK$ and $D^\ast K$ thresholds respectively, which contradicts the
predictions of naive quark models and points out to non-negligible effects of
the $D^{(\ast)}K$ loops in the dynamics of the even-parity scalar ($J^\pi=0^+$)
and axial-vector ($J^\pi=1^+$) $c\bar s$ systems. Recent lattice QCD studies,
incorporating the effects of the $D^{(\ast)}K$ channels, analyzed these
spin-parity sectors and correctly described the
$D^\ast_{s0}(2317)-D_{s1}(2460)$ mass splitting. Motivated by such works, we
study the structure of the $D_{s0}^\ast(2317)$ and $D_{s1}(2460)$ resonances in
the framework of an effective field theory consistent with heavy quark spin
symmetry, and that incorporates the interplay between $D^{(\ast)}K$ meson-meson
degrees of freedom and bare P-wave $c\bar s$ states predicted by constituent
quark models. We extend the scheme to finite volumes and fit the strength of
the coupling between both types of degrees of freedom to the available lattice
levels, which we successfully describe. We finally estimate the size of the
$D^{(\ast)}K$ two-meson components in the $D^\ast_{s0}(2317)$ and
$D_{s1}(2460)$ resonances, and we conclude that these states have a
predominantly hadronic-molecular structure, and that it should not be tried to
accommodate these mesons within $c\bar{s}$ constituent quark model patterns.
