Abstract: Expandable intervertebral spacer implants are illustrated for insertion into an intervertebral space between a superior vertebral body and an inferior vertebral body. The implant is formed as a first and second member having a variable distance therebetween, each member having a first end and a second end with a length therebetween, a proximal side and a distal side with a width therebetween, and a pair of internally guided legs which are rotatable about one or more common axes and are positioned to successively interlock with a plurality of detents formed within each said first and second members to facilitate maintenance of a specific distance therebetween.