Embodiments disclosed herein relate to devices implantable into a human lung, for example to reduce the volume of air trapped in a diseased portion of the lung to prevent inhalation while permitting expiration out of the diseased portion. In some embodiments, the device comprises a distal portion with an anchor system that may anchor the device into tissue of an air passageway wall, and the distal portion may be connected to a proximal portion via a flexible portion that permits the distal portion to articulate substantially with respect to the proximal portion, such that the distal portion and the proximal portion may be non-collinear along a longitudinal axis of the distal portion. This may facilitate implantation of the device into a non-linear air passageway.
