上隅骨

thumb|Skull diagram of the dinosaur Proceratosaurus, showing location of surangular thumb|Skull and jaws diagram of the primitive Synapsida|synapsid [[Dimetrodon, showing location of surangular]] The surangular or suprangular is a jaw bone found in most land vertebrates, except mammals. Usually in the back of the jaw, on the upper edge, it is connected to all other jaw bones: dentary, angular, splenial and articular. It is often a muscle attachment site. It has been noted in dinosaurs.