Classification

The Classification of dinosaurs.

    Dinosaurs are classified into two major groups the Ornithischia (the bird-hipped) and the Saurischia (lizard-hipped). This classification is related to the structure of the dinosaurs hip joints.

      Ornithischia

The Ornithischian dinosaurs have the hip bones arranged where the pubis lies back against the ischium, and arrangement similar to that seen in birds.

     Saurischia

The Saurischian dinosaurs have hip bones arranged so that the three bones on each side of the hip radiate outward from the hip socket.
The illium connects with the vertebrae (the spinal cord) providing stability.
The lower two bones, the Pubis and the Ischium point in opposing directions. Providing areas for the leg muscles to attach too.

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Ornithischia
	The Ornithischian dinosaurs have the hip bones arranged where the pubis lies back against the ischium, and arrangement similar to that seen in birds.

Saurischia
	The Saurischian dinosaurs have hip bones arranged so that the three bones on each side of the hip radiate outward from the hip socket. The illium connects with the vertebrae (the spinal cord) providing stability. The lower two bones, the Pubis and the Ischium point in opposing directions. Providing areas for the leg muscles to attach too.