Editing Pterosaur (section)

===Shoulder girdle===
[[File:UCMP Pteranodon dorsal body.JPG|thumb|The shoulder girdle connected to the notarium]]
The [[shoulder girdle]] was a strong structure that transferred the forces of flapping flight to the [[thorax]]. It was probably covered by thick muscle layers.{{sfn|Witton|2013|p=44}} The upper bone, the [[shoulder blade]], was a straight bar. It was connected to a lower bone, the [[coracoid]] that is relatively long in pterosaurs. In advanced species, their combined whole, the scapulocoracoid, was almost vertically oriented. The shoulder blade in that case fitted into a recess in the side of the notarium, while the coracoid likewise connected to the breastbone. This way, both sides together made for a rigid closed loop, able to withstand considerable forces.{{sfn|Witton|2013|p=31}} A peculiarity was that the breastbone connections of the coracoids often were asymmetrical, with one coracoid attached in front of the other. In advanced species the shoulder joint had moved from the shoulder blade to the coracoid.{{sfn|Witton|2013|p=32}} The joint was saddle-shaped and allowed considerable movement to the wing.{{sfn|Witton|2013|p=31}} It faced sideways and somewhat upwards.{{sfn|Wellnhofer|1991|p=52}}

The breastbone, formed by fused paired ''sterna'', was wide. It had only a shallow keel. Via sternal ribs, it was at its sides attached to the dorsal ribs.{{sfn|Wellnhofer|1991|p=51}} At its rear, a row of belly ribs or [[gastralia]] was present, covering the entire belly.{{sfn|Wellnhofer|1991|p=52}} To the front, a long point, the ''cristospina'', jutted obliquely upwards. The rear edge of the breastbone was the deepest point of the thorax.{{sfn|Witton|2013|p=32}} Clavicles or interclavicles were completely absent.{{sfn|Wellnhofer|1991|p=52}}