Cervical Vertebrae
Irregular bones belonging to the axial skeleton (the central core)
Also known as: Neck Bones
Classification
Irregular bones belonging to the axial skeleton (the central core)
Dimensions
Typically the smallest bones in the spine, these are thin and delicate compared to the thick bones of the lower back. They are often wider than they are deep to allow for a broad range of movement.
Key Features
Look for a small, ring-like or square-shaped central body with thin, wing-like projections extending to the sides. The most telling feature is the presence of small holes on the sides (transverse foramina) which serve as protected pathways for blood vessels. The very top bone is shaped like a simple ring, while the second bone has a distinctive peg-like bump on top that fits into the first ring.
Similar Bones
They can be confused with the bones of the middle back (thoracic vertebrae). To tell them apart, check for the small holes on the sides; neck bones have them, while back bones do not. Back bones also usually have much longer, downward-pointing spikes on the back that look like a giraffe's nose when viewed from the side.
Across Species
Most mammals, from the tiny mouse to the towering giraffe, possess exactly seven neck bones. In a giraffe, these bones are incredibly elongated, sometimes reaching over ten inches in length each. In contrast, whales have neck bones that are highly compressed and often fused together to support their heavy heads while swimming. The blue sections in the illustration represent intervertebral discs, which act as rubbery cushions between the bones and are much thicker in animals that require high neck flexibility.
Evolutionary History
Neck bones evolved as early land animals needed to move their heads independently of their bodies to hunt and look for predators. Ancient lobe-finned fish had heads directly attached to their shoulder girdles, but as amphibians and early reptiles emerged, the first neck bones appeared, creating a transition zone that eventually allowed for the complex, multi-directional rotation seen in modern mammals.
Photography Tips
Place the bone on a dark, non-reflective background. Take one photo looking straight down through the central hole and another from the side to show the profile of the wing-like projections. Including a coin or a ruler in the frame is essential for showing the small scale of these bones.
Notes
What is the blue part of the bone?