Pneumaticity is the presence of air spaces or cavities within bones, which are produced when air sacs, attached to the lungs, invade said bones.
Dinosaur pneumaticity may be directly linked to a "flow through" breathing system as seen in modern birds, or serve to lighten the bones as seen in, well, modern birds. Heck, pneumaticity may be there for some as-yet unknown reason, as is the case with human sinuses; we know we have them but no-one really knows what they do, other than get bunged up with gunk when we get a cold.
Dinosaur pneumaticity may be directly linked to a "flow through" breathing system as seen in modern birds, or serve to lighten the bones as seen in, well, modern birds. Heck, pneumaticity may be there for some as-yet unknown reason, as is the case with human sinuses; we know we have them but no-one really knows what they do, other than get bunged up with gunk when we get a cold.
