Air sac

This article is about a component of dinosaur and bird skeletal systems. For the structures in mammalian lungs, see air sac (lung).

Air sacs are spaces within an organism where there is the constant presence of air. Among modern animals, birds possess the most air sacs (9–11), with their extinct dinosaurian relatives showing a great increase[clarification needed] in the pneumatization (presence of air) in their bones.[1] Birds use air sacs for respiration as well as a number of other things.[2][clarification needed] Theropods, like Aerosteon, have many air sacs in the body that are not just in bones, and they can be identified as the more primitive form of modern bird airways.[3][clarification needed] Sauropods are well known for the large number of air pockets in their bones (especially vertebra), although one theropod, Deinocheirus, shows a rivalling number of air pockets.[4][5]

  1. ^ Cite error: The named reference Romer_1977 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference :0 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Sereno_2008 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Lee_2014 was invoked but never defined (see the help page).
  5. ^ Schwarz-Wings D, Meyer CA, Frey E, Manz-Steiner HR, Schumacher R (January 2010). "Mechanical implications of pneumatic neck vertebrae in sauropod dinosaurs". Proceedings. Biological Sciences. 277 (1678): 11–17. doi:10.1098/rspb.2009.1275. PMC 2842622. PMID 19801376.