US Patent 8123810 Expandable intervertebral implant with wedged expansion member

An expandable intervertebral implant is described for insertion between vertebrae of a human spine. The intervertebral implant includes an upper body that engages a first vertebra of the human spine, a lower body that engages a second vertebra of the human spine, an insert, and an expansion member. The expansion member may include a first angled portion and a second angled portion. The expansion member may be advanced such that a first angled portion of the expansion member engages an angled portion of the insert to increase a separation distance between the upper body and the lower body of the intervertebral implant. An advancing element may engage a second angled portion of the expansion member such that a direction of advancement of the advancing element is different than the direction of advancement of the expansion member.