The high-speed drumming motion of the golden-fronted woodpecker causes a tremendous amount of stressed force on the animal, termed “incident mechanical excitations.” The hyoid bone, located in the cranium, secures and diverts vibrational forces away from the brain.
The hyoid bone is a strong, flexible bone covered in muscle that allows the woodpecker to extend its tongue out of its beak to grab food. It also serves as an attachment site for muscles around the throat, tongue, and head.
The hyoid bone begins in the nostril of the upper beak, where it divides into two parts between the eyes, and then travels over the top of the skull and around the back. At the base of the skull, the separate pieces rejoin and attach to the muscle of the tongue (see diagram). The woodpecker not only uses the hyoid bone to gather food for meals, but to protect the brain from neurological trauma. This happens in two ways.
First, when the woodpecker pecks a tree, the muscles surrounding the relaxed hyoid bone contract, propelling the tongue forward inside the beak, and forward even farther when collecting food. The tension results from the contracted muscles pulling on the hyoid bone. This tension stabilizes the cranium and spine, acting as a “seat belt” to prevent excessive movement of the brain.
Second, the hyoid bone design diverts vibrations (and any forceful impact) away from the cranium. Because of its longer length, the upper beak will absorb more of the shock than the lower beak when striking a surface. The forces will then travel up the beak where they will encounter the hyoid bone in the nostril before they hit the spongy bone in the skull. The stress forces will then travel along the path of the hyoid bone, rather than continuing to the skull, diffusing into the muscles covering the bone, or traveling to the tongue.
You can see an illustration of this strategy on AskNature.