Picture of the Adenoids

Human Anatomy

Medically Reviewed by Carol DerSarkissian, MD on June 23, 2021
2 min read

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The adenoids are a mass of soft tissue behind the nasal cavity. Like lymph nodes, adenoids are part of the immune system and are made of the same type of tissue (lymphoid tissue). White blood cells circulate through the adenoids and other lymphoid tissue, reacting to foreign invaders in the body. 

We all have adenoids at birth and in childhood, but as we head into adolescence they start to shrink. By adulthood, most people's adenoids have disappeared.

  • Adenoiditis: Inflammation of the adenoids, often from infection. Bacteria or viruses may cause adenoiditis.
  • Enlarged adenoids: In children, the adenoids can get larger because of infection or reasons that are unclear. Very large adenoids can interfere with breathing or with the flow of mucus.
  • Obstructive sleep apnea: While sleeping, enlarged adenoids may intermittently block the flow of air through the throat. This can cause a person to stop breathing for a few seconds (known as apnea) and can occur several times each night.
  • Ear infections (otitis): In children, enlarged adenoids may block the Eustachian tubes, which drain fluid from the ears into the throat. If these tubes are unable to drain, it can lead to repeated ear infections.
  • Endoscopy: A small, flexible tube with a lighted camera on the end is inserted into the nose or throat. A doctor can view the nasal passages and adenoids on a video screen during endoscopy.
  • Computed tomography (CT): A CT scanner takes multiple X-rays, and a computer constructs detailed images of the sinuses, nasal cavities, and adenoids. 
  • Magnetic resonance imaging (MRI): An MRI scanner uses a high-powered magnet and a computer to create highly detailed images of the nasal passages, sinuses, and adenoids.


  • Adenoids surgery (adenoidectomy): Surgery to remove the adenoids is often required when the adenoids are large enough to cause other health problems. Children's adenoids may be removed surgically with no apparent ill effects.
  • Antibiotics: Antibiotics kill bacteria, usually curing sinus or ear infections caused by bacteria.