( which ( ( is ( ( the layer ) ( that ( binds ( ( the skin ) ( of ( ( the ( ( palm or ) sole ) ) ( to ( the ( underlying skeleton ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (WDT which)) (VP (VBZ is) (NP (NP (DT the) (NN layer)) (SBAR (WHNP (WDT that)) (S (VP (VBZ binds) (NP (NP (DT the) (NN skin)) (PP (IN of) (NP (NP (DT the) (NN palm) (CC or) (NN sole)) (PP (TO to) (NP (DT the) (VBG underlying) (NN skeleton))))))))))) (. .)))
which is the layer that binds the skin of the palm or sole to the underlying skeleton.
(ROOT (S (NP (NP (DT The) (JJ thick) (NN skin)) (, ,) (VP (VBN found) (ADVP (RB only)) (PP (IN on) (NP (NP (NP (DT the) (NNS palms)) (PP (IN of) (NP (DT the) (NNS hands)))) (CC and) (NP (NP (DT the) (NNS soles)) (PP (IN of) (NP (DT the) (NNS feet))))))) (, ,)) (VP (VBZ has) (NP (DT an) (JJ extra) (NN layer))) (. .)))