Ultimobranchial body

The ultimobranchial body or gland is a small organ found in the neck region of many animals.

In humans, the ultimobranchial body is an embryological structure that gives rise to the calcitonin-producing cells&mdash;also called parafollicular cells or clear cells&mdash;of the thyroid gland. In humans, this body is a derivative of the ventral recess of the fourth pharyngeal pouch (or fifth)