Scapula
Flat bone, part of the appendicular skeleton
Also known as: Shoulder Blade
Classification
Flat bone, part of the appendicular skeleton
Dimensions
Varies widely by animal size, typically forming a thin, triangular or elongated flat plate with a prominent ridge running across one surface.
Key Features
Recognizable by its flat, blade-like body crossed by a prominent raised ridge on the back surface, tapering down to a narrower end featuring a socket connection point.
Similar Bones
Can be confused with large pelvic fragments or other flat bones, but is distinguished by its characteristic long spine-like ridge dividing the surface into two main hollowed areas.
Across Species
In humans, the shoulder blade is a broad, flat triangle that lies flush against the upper back. In running animals like horses and dogs, it becomes much longer and narrower, sliding along the side of the chest to give a longer stride. In flying birds, it fuses with other elements to form a sturdy brace for wing muscles.
Evolutionary History
The shoulder blade has ancient origins among land-dwelling vertebrates, evolving from part of the shoulder girdle that connected the front limbs to the main body trunk and supported locomotion on land.
Photography Tips
Photograph from the top-down flat perspective to capture the entire outline and the ridge running across the surface. Use side-angled lighting to make the raised ridge stand out, and always include a ruler or standard scale reference.