If a giraffe’s neck only has seven vertebrae, how is it so flexible?
Certain characteristics of giraff necks give them a flexibility rivaling any Slinky. The first feature is the way that the vertebrae in the neck, called the cervical vertebrae, are joined together. Remember that giraffes have seven of these bones, just like we do. However, giraffe cervical vertebrae are bound together with ball-and-socket joints [source: Owen]. These are the kinds of joints that link your arm with your shoulder and offer a 360-degree range of motion. Also, the joint between its neck and skull permits the giraffe to extend its head almost completely perpendicular to the ground.
Moving down to where the neck meets the back, we find the second important anatomical feature for the giraffe’s slinkiness. We call the vertebrae in the top portion of our backs the thoracic vertebrae. In humans, thoracic vertebrae are joined at the middle of the bone to provide added stability; and our cervical vertebrae fuse at the front and back for more mobility. Giraffe anatomy doesn’t follow this same construction, and its first and second thoracic vertebrae are bound in the same way that its cervical ones are, with ball-and-socket joints [source: Dagg and Foster]. That adaptation gives the giraffe an extra point of flexibility. It also accounts for the giraffe’s signature hump [source: Encarta].
As another result of the long neck, a giraffe’s blood has a long journey to travel. For that reason, the anatomy of a giraffe is quite amazing.