A device to space apart vertebral members comprising: an upper endplate comprising a first engagement surface configured to engage a first vertebra and an opposite inner surface, the upper endplate comprising first projections (38a, 38b, 38c, 38d) extending from the inner surface, the first projections (38a, 38b, 38c, 38d) each comprising a first inclined surface (44a, 44b, 44c, 44d); a lower endplate comprising a second engagement surface configured to engage a second vertebra that is adjacent to the first vertebra and an opposite inner surface, the lower endplate comprising second projections (58a, 58b, 58c, 58d) extending from the inner surface of the lower endplate, the second projections (58a, 58b, 58c, 58d) each comprising a second inclined surface (64a, 64b, 64c, 64d); and a wedge positioned between the endplates (22, 24), the wedge comprising first mating parts (80a, 80b, 82a, 82b) that engage the first inclined surfaces (44a, 44b, 44c, 44d) and second mating parts (86a, 86b, 88a, 88b) that engage the second inclined surfaces (64a, 64b, 64c, 64d), wherein the wedge is movable relative to the endplates (22, 24) to move the device between a first configuration having a first height between the engagement surfaces (34, 54) and a second configuration having an increased second height between the engagement surfaces (34, 54); a frame having an interior cavity, at least a portion of the endplates and the wedge being positioned within the interior cavity as the device moves between the first and second configurations, wherein the frame comprises a plurality of rails (108a, 108b, 110a, 110b, 112a, 112b) that define recesses therebetween, the projections (38a, 38b, 38c, 38d, 58a, 58b, 58c, 58d) each being disposed in one of the recesses such that side surfaces of the projections (38a, 38b, 38c, 38d, 58a, 58b, 58c, 58d) engage two of the rails (108a, 108b, 110a, 110b, 112a, 112b) and the projections (38a, 38b, 38c, 38d, 58a, 58b, 58c, 58d) translate within the recesses as the device moves between the first and second configurations. an upper endplate comprising a first engagement surface configured to engage a first vertebra and an opposite inner surface, the upper endplate comprising first projections (38a, 38b, 38c, 38d) extending from the inner surface, the first projections (38a, 38b, 38c, 38d) each comprising a first inclined surface (44a, 44b, 44c, 44d); a lower endplate comprising a second engagement surface configured to engage a second vertebra that is adjacent to the first vertebra and an opposite inner surface, the lower endplate comprising second projections (58a, 58b, 58c, 58d) extending from the inner surface of the lower endplate, the second projections (58a, 58b, 58c, 58d) each comprising a second inclined surface (64a, 64b, 64c, 64d); and a wedge positioned between the endplates (22, 24), the wedge comprising first mating parts (80a, 80b, 82a, 82b) that engage the first inclined surfaces (44a, 44b, 44c, 44d) and second mating parts (86a, 86b, 88a, 88b) that engage the second inclined surfaces (64a, 64b, 64c, 64d), wherein the wedge is movable relative to the endplates (22, 24) to move the device between a first configuration having a first height between the engagement surfaces (34, 54) and a second configuration having an increased second height between the engagement surfaces (34, 54); a frame having an interior cavity, at least a portion of the endplates and the wedge being positioned within the interior cavity as the device moves between the first and second configurations, wherein the frame comprises a plurality of rails (108a, 108b, 110a, 110b, 112a, 112b) that define recesses therebetween, the projections (38a, 38b, 38c, 38d, 58a, 58b, 58c, 58d) each being disposed in one of the recesses such that side surfaces of the projections (38a, 38b, 38c, 38d, 58a, 58b, 58c, 58d) engage two of the rails (108a, 108b, 110a, 110b, 112a, 112b) and the projections (38a, 38b, 38c, 38d, 58a, 58b, 58c, 58d) translate within the recesses as the device moves between the first and second configurations.