Changes

**Excavated to contain air spaces, such as the skull in the instance of paranasal sinuses, and the post-cranial skeleton of birds

**Excavated to contain air spaces, such as the skull in the instance of paranasal sinuses, and the post-cranial skeleton of birds

==Composition of Bone==

==Composition of Bone[[Bones and Cartilage - Anatomy & Physiology|right|top]]==

[[Image:Bone histo.jpg|right|thumb|100px|<small><center>Histological structure of bone (Courtesy of RVC Histology images)</center></small>]]

[[Image:Bone histo.jpg|right|thumb|100px|<small><center>Histological structure of bone (Courtesy of RVC Histology images)</center></small>]]

[[Image:Bone micro structure.jpg|right|thumb|100px|<small><center>Microscopic bone (Courtesy of RVC Histology images)</center></small>]]

[[Image:Bone micro structure.jpg|right|thumb|100px|<small><center>Microscopic bone (Courtesy of RVC Histology images)</center></small>]]