Editing Acromion (section)

==In other animals==
The '''acromion process''' of [[bat]]s ([[Mammalia]]: [[Chiroptera]]) is particularly elongated compared to that of  [[human]]s.

[[Turtle]]s have an acromion that forms the anterior part of the triradiate [[pectoral girdle]] (together with the [[coracoid]] and [[scapula]]).  In this highly specialized [[Endoskeleton|endoskeletal]] structure, the scapula is a dorsal (directed upwards) process attached to the first rib; the coracoid is a posteroventral (directed backward and down) process; and the acromion is a medioventral (directed inwards and down) process (also known as the prescapular process) located at the base of the scapula.  This had led to some controversy regarding the evolutionary origin of turtles, because in both [[pareiasaur]]s and non-mammalian [[therapsid]]s the acromion is located at the dorsal tip of the scapula.
<ref>{{Harvnb|Rieppel|Reisz|1999| p=}}</ref>

In modern [[turtle]]s, the acromion projects ventrally and articulates with the [[plastron]] (the flat lower part of the shell), but it [[Evolution|evolved]] independently in [[pareiasaur]]s and turtles long before the plastron.<ref>{{Cite journal|title = The evolutionary position of turtles revised|journal = Naturwissenschaften|date = 2001-05-01|issn = 0028-1042|pages = 193–200|volume = 88|issue = 5|doi = 10.1007/s001140100228|pmid = 11482432|first1 = Rafael|last1 = Zardoya|first2 = Axel|last2 = Meyer| bibcode=2001NW.....88..193Z | s2cid=7836810 |url = http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-34962}}</ref>  In these primitive ancestors, the acromion projected forward to form a strong and flexible articulation between the shoulder girdle and the clavicle.  Notwithstanding these changes, the acromion of turtles retains its original function, to support the shoulder girdle and increase stride length.
<ref>{{Harvnb|Lee|1996| loc=Abstract}}</ref>

<gallery>
 File:Snapping turtle shoulder girdle.JPG|The shoulder girdle of a [[snapping turtle]]. (1) Acromion, (2) scapula, and (3) coracoid
</gallery>