Adjustable arcuate implant

An expanding implant for insertion between two regions of tissue, the implant comprising:

• a base having a contact surface for contacting a first region of tissue, said base comprising a proximal portion in sliding engagement with a distal portion so as to define an arcuate path of relative motion between said proximal portion and said distal portion, said base assuming an initial state with a first arcuate extent and being adjustable towards a second state by changing an extent of overlap to vary an arcuate extent of said base;
• a displaceable portion having a contact surface for contacting a second region of tissue;
• a first rigid linking segment having a first end and an opposing second end, said first end including a first articulating connection with said displaceable portion and said second end including a second articulating connection with said distal portion of said base;
• a second rigid linking segment having a first end and an opposing second end, said first end including a third articulating connection with said displaceable portion and said second end including a fourth articulating connection with said proximal portion of said base;
• wherein each one of said first articulating connection, said second articulating connection, said third articulating connection, and said fourth articulating connection is a polyaxial joint such that adjustment of said base from said initial state towards said second state causes an increase in a distance between said contact surfaces of said base and said displaceable portion.