The Collaborative International Dictionary of English v.0.48:
Sustentacular \Sus`ten*tac"u*lar\, a. [See Sustenance.] (Anat.) Supporting; sustaining; as, a sustentacular tissue. [1913 Webster]WordNet (r) 3.0 (2006):
sustentacular adj 1: serving to sustain or support; "sustentacular cells"