Calcaneus
Short bone, part of the appendicular skeleton (lower limb)
Also known as: Heel bone
Classification
Short bone, part of the appendicular skeleton (lower limb)
Dimensions
Robust and blocky in shape, representing the largest of the foot bones, typically measuring several inches in length depending on the overall body scale.
Key Features
Characterized by its large, blocky body, a prominent rear overhang where the powerful calf muscles attach, and distinct articular surfaces on the upper and front sides for connecting with neighboring ankle bones.
Similar Bones
Can be confused with other large tarsal or carpal bones, but its elongated, heavy build and distinct rear anchor shape readily distinguish it from wrist bones or smaller foot elements.
Across Species
In humans, the calcaneus forms a prominent rear heel that supports standing upright and bipedal walking. In digitigrade animals like dogs and cats, this bone is lifted high off the ground as part of the ankle region, forming the point of the hock. In marine mammals like whales, the foot bones are heavily reduced or absent entirely, streamlining the body for swimming.
Evolutionary History
The calcaneus evolved from the tarsal elements of early tetrapods, shifting its proportions over millions of years to support new modes of locomotion, transitioning from sprawling movements to upright, weight-bearing locomotion.
Photography Tips
Capture the bone from a side profile view against a neutral, high-contrast background using soft, angled lighting to highlight the surface contours and the prominent rear projection. Include a small ruler or coin for scale.