Editing Rib (section)

==Other animals==
[[File:Dog anatomy lateral skeleton view.jpg|thumb|right|Skeleton of a dog showing the location of the ribs]]
[[File:Eptesicus fuscus ribcage.jpg|thumb|right|Rib cage of the [[big brown bat]] (''Eptesicus fuscus'')]]
In [[jawed fish]], there are often two sets of ribs attached to the vertebral column. One set, the '''dorsal ribs''', are found in the dividing septum between the upper and lower parts of the main muscle segments, projecting roughly sideways from the vertebral column. The second set, the '''ventral ribs''' arise from the vertebral column just below the dorsal ribs, and enclose the lower body, often joining at the tips. Not all species possess both types of rib, with the dorsal ribs being most commonly absent. [[Shark]]s, for example, have no ventral ribs, and only very short dorsal ribs. In some [[teleost]]s, there may be additional rib-like bones within the muscle mass.<ref name=VB>{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 170–173|isbn= 0-03-910284-X}}</ref>

[[Tetrapod]]s, however, only ever have a single set of ribs which are probably [[homology (biology)|homologous]] with the dorsal ribs of fishes. In the earlier [[tetrapodomorph|choanates]], every vertebra bore a pair of ribs, although those on the [[thoracic vertebra]]e are typically the longest. The [[sacral vertebrae|sacral ribs]] were stout and short, since they formed part of the [[pelvis]], connecting the backbone to the [[hip bone]]s.<ref name=VB/>

In most true tetrapods, many of these early ribs have been lost, and in living [[amphibian]]s and [[reptile]]s, there is great variation in rib structure and number. For example, [[turtle]]s have only eight pairs of ribs, which are developed into a bony or cartilaginous [[carapace]] and [[plastron]], while snakes have numerous ribs running along the full length of their trunk. [[Frog]]s typically have no ribs, aside from a sacral pair, which form part of the pelvis.<ref name=VB/>

In birds, ribs are present as distinct bones only on the thoracic region, although small fused ribs are present on the [[cervical vertebra]]e.  The thoracic ribs of birds possess a wide projection to the rear; this '''uncinate process''' is an attachment for the shoulder muscles.<ref name=VB/> 
Usually dogs have 26 ribs.
Mammals usually also only have distinct ribs on the thoracic vertebra, although fixed cervical ribs are also present in [[monotreme]]s. In [[theria]]n mammals, the cervical and lumbar ribs are found only as tiny remnants fused to the vertebrae, where they are referred to as '''transverse processes'''. In general, the structure and number of the true ribs in humans is similar to that in other mammals. Unlike reptiles, [[caudal vertebrae|caudal]] ribs are never found in mammals.<ref name=VB/>