page_title: Zygomatic bone
section_title: Non-mammalian vertebrates
hierarchical_section_title: Zygomatic bone / Other animals / Non-mammalian vertebrates
caption_attribution_description: Isolated right jugal bone (Os jugale; lateral view) from the skull of the large duckbill dinosaur Edmontosaurus annectens from the Late Cretaceous (Maastrichtian, ~68 million years ago) of North America, in the permanent collection of The Children’s Museum of Indianapolis.
context_page_description: In the human skull, the zygomatic bone is a paired irregular bone which articulates with the maxilla, the temporal bone, the sphenoid bone and the frontal bone. It is situated at the upper and lateral part of the face and forms the prominence of the cheek, part of the lateral wall and floor of the orbit, and parts of the temporal fossa and the infratemporal fossa. It presents a malar and a temporal surface; four processes, and four borders.
context_section_description: In non-mammalian vertebrates, the zygomatic bone is referred to as the jugal bone, since these animals have no zygomatic arch. It is  found in most reptiles, amphibians, and birds. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species.
  This bone is considered key in the determination of general traits of the skull, as in the case of creatures, such as dinosaurs in paleontology, whose entire skull has not been found. In coelacanths and early tetrapods the bone is relatively large. Here, it is a plate-like bone forming the lower margin of the orbit and much of the side of the face. In ray-finned fishes it is reduced or absent, and the entire cheek region is generally small. The bone is also absent in living amphibians.
  With the exception of turtles, the jugal bone in reptiles forms a relatively narrow bar separating the orbit from the inferior temporal fenestra, of which it may also form the lower boundary. The bone is similarly reduced in birds. In mammals, it takes on broadly the form seen in humans, with the bar between the orbit and fenestra vanishing entirely, and only the lower boundary of the fenestra remaining, as the zygomatic arch.
caption: This jugal bone from an Edmontosaurus is over three feet (1 meter) long
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