Ischium the Latin term derives from Greek ἰσχίον "iskhion" meaning "hip joint". The division of the "acetabulum" into "ischium" (ἰσχίον) and "ilium" (λαγών, "os lagonicum") is due to Galen, "De ossibus". Galen, however, omits mention of the "pubis" as a separate bone. The clade Dinosauria is divided into the Saurischia and Ornithischia based on hip structure, including importantly that of the ischium. In the majority of dinosaurs, the ischium extends down from the ilium and towards the tail of the animal. The acetabulum, which can be thought of as a "hip-socket", is a cup-shaped opening on each side of the pelvic
Zygomatic bone 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. The term "zygomatic" derives from the Greek Ζυγόμα "zygoma" meaning "yoke". The zygomatic bone is occasionally referred to as the zygoma, but this term may also refer to the zygomatic arch. Zygomatic bone In the human skull, the zygomatic bone (cheekbone or malar 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