Phalanx
Long bone, part of the appendicular skeleton
Also known as: Finger bone or toe bone
Classification
Long bone, part of the appendicular skeleton
Dimensions
Small and slender, featuring an elongated central shaft with broadened ends for joint connections, varying in length depending on its specific position along the digit.
Key Features
Smooth, rounded joint surfaces at both ends, a narrow middle shaft, and a miniature long-bone profile that fits entirely in the palm of a hand.
Similar Bones
Can be confused with metacarpals or metatarsals from the main part of the hand or foot; finger bones are typically narrower, shorter, and feature distinct joint surfaces on both ends rather than a flat anchoring base.
Across Species
Across the animal kingdom, these bones show incredible adaptability. In bats, they are remarkably elongated to support wings for flight; in whales and dolphins, they are multiplied in number to form broad, sturdy flippers; and in running animals like horses, they are reduced and fused into a single strong hoof-bearing column.
Evolutionary History
Originating from the fin rays of ancient fish ancestors, these skeletal elements transformed as tetrapods adapted to walking on land, gradually shifting from supportive webbed arrays into distinct, weight-bearing digits suited for grasping and locomotion.
Photography Tips
Place the bone on a neutral, non-reflective background with strong, even side-lighting to highlight surface curves and bumps, and include a small ruler or coin for scale reference.