Atelectasis be bibasal in pattern. Chest CT or Bronchoscopy may be necessary if the cause of atelectasis is not clinically apparent. Direct signs of atelectasis include displacement of interlobar fissures and mobile structures within the thorax, overinflation of the unaffected ipsilateral lobe or contralateral lung, and opacification of the collapsed lobe. Atelectasis may be an acute or chronic condition. In acute atelectasis, the lung has recently collapsed and is primarily notable only for airlessness. In chronic atelectasis, the affected area is often characterized by a complex mixture of airlessness, infection, widening of the bronchi (bronchiectasis), destruction, and scarring (fibrosis). The atmosphere
Ultimopharyngeal body during development. Failure of development of ultimobranchial body is seen in DiGeorge syndrome. Ultimopharyngeal body The ultimopharyngeal body or ultimobranchial body or ultimobranchial 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—also called parafollicular cells or C cells—of the thyroid gland. In humans, this body is a derivative of the ventral recess of the fourth pharyngeal pouch (technically fifth, but that one is rudimentary and merges with the fourth). The cells that give rise to the parafollicular cells are actually