[[Image:Bird skull.jpg|thumb|right|200px|'''Bird skull''', nabrown, 2008]] Birds have '''pneumatised skull bones''' which connect to airways in the head rather than the air sacs. They have large orbits and their skull plates are separated by spongy bone. A '''single occipital condyle''' articulates with the '''atlas''' allowing more rotation of the head. In parrots, the nasal bone and frontal bone are joined by a flexible cartilage structure allowing greater jaw opening which is called the craniofacial hinge. This allows kinesis to occur. Birds have thin '''jugal arches''' (equivalent to zygomatic arch) and the middle ear contains only the columella (equivalent to the stapes). <br> <br> | [[Image:Bird skull.jpg|thumb|right|200px|'''Bird skull''', nabrown, 2008]] Birds have '''pneumatised skull bones''' which connect to airways in the head rather than the air sacs. They have large orbits and their skull plates are separated by spongy bone. A '''single occipital condyle''' articulates with the '''atlas''' allowing more rotation of the head. In parrots, the nasal bone and frontal bone are joined by a flexible cartilage structure allowing greater jaw opening which is called the craniofacial hinge. This allows kinesis to occur. Birds have thin '''jugal arches''' (equivalent to zygomatic arch) and the middle ear contains only the columella (equivalent to the stapes). <br> <br> |