The Stroh formalism and analytic continuation approach are used to dev
elop a systematic study for two-dimensional line defects in anisotropi
c elastic solids. The line defects are classified as either belonging
to the craze type or line inhomogeneity type. A crack and rigid line a
re considered as two special cases of these categories. The governing
equations, given in terms of the Stroh matrix notation, show many comp
lementary features between these two line defects. In addition, a disc
ussion is given showing why the line defect field cannot in general be
developed from the Eshelby inclusion solution [1], except for the spe
cial cases of a crack and rigid line inhomogeneity.