A structure that serves as a stay or support to another. ... Origin: L. A prop, fr. Sustento, to hold upright ... (05 Mar 2000) ... 
(sus″tәn-tak´u-lәm) Latin word meaning a support. a term used in anatomy. adj., sustentac´ular., adj.
Type: Term Pronunciation: sŭs′ten-tak′yū-lŭm, -lă Definitions: 1. A structure that serves as a stay or support to another.
sustentaculum 1. A strong, moveable spine inserted near the termination of the tarsus of each posterior leg, on the under side, as with some spiders. 2. Some species are aided by peculiar spines (called sustentacula) attached to the last joints of the posterior legs.
Latin = a support, which sustains; sustentaculum tali - the ledge on the calcaneus supporting part of the talus.