This is an uncommon bone cancer that most commonly arises from flat bones of the skull, but can arise from other flat bones (ex: ribs, pelvic, shoulder). (cuvs.org)
These are the areas where the immature bones of the skull are still growing together. (womenandinfants.org)
The dense bone of the skull and palate does not allow sound waves to penetrate thus making this diagnostic tool useless for your purpose. (halifaxveterinaryhospitalinc.com)