Metatarsal II
Long Bone; part of the limb (appendicular) skeleton
Also known as: Second Foot Bone or Long Bone of the Second Toe
Classification
Long Bone; part of the limb (appendicular) skeleton
Dimensions
A slender and elongated bone, usually the longest of its neighbors in the mid-foot area, featuring a narrow shaft with slightly expanded ends.
Key Features
This specific bone is recognized by its long, straight central shaft and a distinctive triangular base at the top end. It is unique among its neighbors for sticking out slightly further back toward the ankle, locking into a notch between the smaller cube-shaped ankle bones to create a very stable central arch.
Similar Bones
It can be easily confused with the Metacarpals (the long bones of the hand). However, foot bones are generally narrower, more compressed from side-to-side, and lack the rounded, bulbous 'knuckle' tops found on the hand bones. It also looks like its neighbor, the Third Metatarsal, but the Second is typically longer and has a more complex, wedged base.
Across Species
In many animals, these mid-foot bones are highly specialized. For instance, in horses, the second metatarsal is significantly reduced to a small 'splint bone,' while the third becomes the main weight-bearing cannon bone. In birds, multiple metatarsals fuse together to create a single, strong tarsometatarsus, providing a stable platform for perched landing and powerful takeoffs.
Evolutionary History
These bones originated in early land-dwelling vertebrates as simple structural bars for crawling. Over millions of years, they lengthened and reorganized to facilitate different types of movement, from the flat-footed shuffle of early mammals to the efficient, toe-running stride of modern hunters and the specialized hopping of macropods like kangaroos.
Photography Tips
To capture the best identification features, take a photo from directly above the foot to show the relative lengths of the bones. A second 'profile' shot from the side helps show the natural arch of the bone's shaft. Always place a common object like a coin or a ruler next to the specimen to provide a clear sense of scale.
Notes
what is the highlighed part