SINIS´TRAD, _a._ Toward the left.
SINISTRAL, _a._ On the left side.
SI´NUS, _n._ Name of numerous and various cavities of the body.
SKEL´ETON, _n._ Sum of the bones of a body. It generally means only
the _endoskeleton_ proper, or internal bony framework of the body, as
distinguished from _exoskeleton_ or _dermoskeleton_.