Palpation of the thyroid tumor in a cat with hyperthyroidism. To do this, Dr. Peterson uses his thumb and forefinger and gently feels on both sides of the cat's trachea (windpipe) from the larynx (voice box) to where the trachea decends into the chest cavity. As the cat's thyroid gland develops a tumor and enlarges, the thyroid tumor commonly falls from it's normal location just below the larynx and may even fall into the chest cavity where it cannot be palpated.