Medical devices suitable for implantation in spaces between bones aredescribed. Anexample medical device suitable for use as an intervertebral spacer includes amainbody having an exterior proximal wall, an exterior distal wall, a firstexterior lateralwall, a second exterior lateral wall, an upper surface, a lower surface, aninteriorproximal wall, an interior distal wall, a first interior lateral wall, asecond interiorlateral wall, and a longitudinal axis. The interior proximal wall, theinterior distalwall, the first interior lateral wall, and the second interior lateral wallcooperativelydefine an interior cavity. The first and second exterior lateral walls areoutwardlydirected at an angle from the lower surface to the upper surface relative tothelongitudinal axis.
