Many low-mass stars in the Orion nebula are associated with very compact (≃ 1 arcsec) emission knots, known variously as proplyds, PIGs or LV knots. Some of these knots are teardrop-shaped, with “tails” pointing away from the massive star θ
1 Ori C, which is the principal exciting star of the nebula. We discuss models of such knots, which invoke the interaction of the fast stellar wind from θ
1 Ori C with a transonic photoevaporated flow from the surface of an accretion disk around a young low-mass star. We review previous analytic work and compare the results of the model with the observed brightnesses, morphologies and emission line profiles of the knots, as well as presenting new results from numerical hydrodynamical simulations.