Capitate
Short bone, part of the limb (appendicular) skeleton
Also known as: Head-shaped wrist bone, Large carpal
Classification
Short bone, part of the limb (appendicular) skeleton
Dimensions
This is the largest of the wrist bones, appearing somewhat like a stout rectangular block with a rounded, head-like dome on its upper side.
Key Features
Look for a distinctively 'head-shaped' rounded top that fits into a socket formed by neighboring bones. It is the central pillar of the wrist, sitting directly above the long bone of the middle finger.
Similar Bones
It can be confused with the Hamate, but the Hamate has a unique hook-like projection on its front side, whereas the Capitate is characterized by its smooth, rounded 'head' and central position.
Across Species
While humans have a versatile capitate for fine motor skills, in hoofed animals like horses, these wrist bones (the 'knee' of the front leg) are tightly packed and cube-shaped to absorb the shock of running. In bats, this bone is elongated to help support the complex mechanics of flight.
Evolutionary History
This bone originates from a series of small, mosaic-like elements found in the fins of ancient lobe-finned fish. Over millions of years, as land-dwelling vertebrates emerged, these elements became more specialized to provide a stable central anchor for the hand and digits.
Photography Tips
Position the bone so the rounded 'head' is clearly visible. Take photos from both the front and back views, and include a coin or ruler to show the small scale of these intricate wrist elements.
Notes
what is the highlighed part