Lateral Cuneiform
Short bone; part of the limb (appendicular) skeleton within the midfoot.
Also known as: Third Cuneiform or Outer Wedge Bone
Classification
Short bone; part of the limb (appendicular) skeleton within the midfoot.
Dimensions
A small, wedge-shaped bone that is roughly four-sided. It is typically the middle-sized of the three 'wedge' bones in the foot, longer than it is wide.
Key Features
It looks like a small, blunt wedge or a lopsided cube. It has several flat, smooth surfaces where it touches its neighbors. Its most distinctive feature is that it sits right in the center of the foot's arch, nestled between the navicular and the long bones of the toes.
Similar Bones
It is often confused with its two neighbors, the Intermediate and Medial Cuneiforms. The Lateral Cuneiform is specifically the one that lines up with the third toe (counting from the big toe). It is smaller than the Medial Cuneiform but slightly larger and more complex in shape than the Intermediate Cuneiform.
Across Species
While humans use these bones to support a stable arch for upright walking, in many tree-dwelling primates, these bones are more flexible to allow the foot to grasp branches. In hoofed animals like horses, many of these mid-foot bones are fused or reduced to provide a rigid, high-speed lever for running.
Evolutionary History
These bones evolved from a primitive pattern of many small, similar pebbles in the feet of early land-dwelling vertebrates. Over millions of years, they specialized into distinct wedge shapes that lock together, allowing for the complex weight-bearing arch that defines the modern vertebrate foot.
Photography Tips
To identify this bone, take photos from the top (dorsal) view of the foot to see its position in the row. A side view is also helpful to see how it fits into the arch. Always include a coin or ruler nearby to show the small scale.
Notes
what is the highlighed part