What type of joint is between the ribs and coastal carilage?

Costochondral joint ( Costo- = Rib, Chondro- = Cartilage) - these joints 'articulate' the ribs with the costal cartilage of the thoracic wall. However, there is no movement between the two.

The Structural Classification for this joint is; Cartilaginous (Synchodrosis).

The Functional Classification for this joint is; Synarthrosis.