Nasal and Sinus Anatomy (and Histology)


External Nose:

the external nose – the part of the nose that you see – is there for more than just to make your child beautiful.  Those cartilage and bone structures are there to keep the nasal airway open.  Think of the boxer with the pulverized nose who can no longer breathe through his nose.  Anyone who has ever broken their nose – elbow during basketball, softball to the nose, whatever – knows that having those structures intact helps keep your nose open, helps keep your breathing open and smooth.

Nasal Cavities:

where all the action takes place:

  • air conditioning – humidification, warming or cooling incoming airstream
  • filter the incoming airstream of microorganisms and pollutants
  • immune function – preventing infection by airborne microorganisms
  • olfaction – sense of smell
  • voice quality – affects voice resonance

Nasal Septum:

divides the nose into right and left halves.  If the nasal septum is deviated (born like that or acquired from trauma), obstruction can result.  If severe enough, septal deviation may warrant surgery (septoplasty) to improve nasal airway.

Lateral View, Upper Airway

Lateral Nasal Airway: Turbinates, Adenoids, Eustachian Tube Opening


3 swellings along the side wall of the nasal cavity.  Their function:

  • create turbulent airflow – this aides in sense of smell, and helps mucus trap microorganisms and pollutants in the airstream (a good thing)
  • cover the openings to the paranasal sinuses (why, we don’t know)
  • alter voice resonance ? (we’re pretty much guessing here)


The Adenoids lie in the nasopharynx at the very back of the nose.  The adenoid tissue is lymphoid tissue.  It looks well, pretty gross.  It is involved in killing microorganisms that are captured by the nasal secretions. Those secretions are swept to the back of the lose by cilia motion.  This is the area where the nose, sinuses, adenoids and tonsils, and the openings to the Eustachian tubes (to the middle ears), all connect.

Therefore, in a way, the adenoids are sort of a key to keeping everything here (nose, sinuses, eustachian tube and middle ears) healthy.  Unhealthy adenoids – acute or chronic adenoiditis – can be a cause of major nose, sinus, and ear problems.

If you look at the picture below, taken through the mouth using an angled endoscope, looking forward toward the front of the nose, the top of the palate is at the bottom, you can see the nasal septum in the middle, the nasal turbinates attached to either side of the nose, the Eustachian tube opening on the right side is visible (there is one on the left also), and the adenoids at the top of it all.

If the adenoids are too big, they can block the nose – nasal obstruction.  The result is difficulty breathing through the nose, and probable rhinitis and sinusitis.

View of Back of Nose: Adenoids, Turbinates, Back of Septum

Paranasal Sinuses:

pediatric sinusitis pediatric allergies allergic rhinitis children toddlers infants

Frontal, Ethmoid (E), and Maxillary (M) Sinuses

air-filled cavities within the bones of the face, connected to the nasal cavities.   There is great variation in sinus shape and size between people.  Have uncertain role; some speculate that they help lighten the facial skeleton, sort of like hollow bird bones make them lighter.

The sinuses consist of four paired cavities each of which is named after the bone in which it is located.  The four sinus pairs:

  • Maxillary sinuses – in bones of cheeks, one on each side.  May grow to be as large as 15ml (could hold about 3 tablespoons).
  • Ethmoid sinuses – usually 6 – 10 per side, situated between the orbits (eye sockets), up to the skull base.  Responsible for more complications from sinusitis than other sinuses, usually involving the orbits (eye sockets) and tissues around the eyes.  The Ethmoid sinuses are small and irregular, sort of like the “nooks and crannies” that you see when you cut open an English muffin.
  • Sphenoid sinus – 1 or 2 lie in the very middle of the head, surrounded by the pituitary (part of the brain), optic nerves (from the eyes), internal carotid arteries – all important structures.  Rarely a source of sinusitis complications, but due to location, complications can be life-threatening (meningitis, brain abscess).
  • The Frontal sinuses – situated in the eyebrow area of forehead bone of the skull.  Usually one each side, but one or both are absent in about 5% of us.  Due to the fact that the brain is just behind the frontal bones, sinusitis complications in the frontal sinuses can be serious (meningitis, brain abscess); fortunately this is rare.


The lining of the nose is our first line of defense against airborne microorganisms and pollutants.  This task is handled by the epithelium through mucociliary clearance (more about this in another post).  The nasal epithelium functions to:

  • Acts as a physical barrier to inhaled foreign materials
  • Entraps and clears foreign material by …
  • Mucus secretion and
  • Cilia activity
  • Is an active part of our immune response – contains enzymes and antibodies
  • Helps condition the air we breathe in: warm it, cool it, moisturize it

Respiratory Epithelium: Nasal and Sinus

Nasal (and sinus) epithelium:

is comprised of

  • cells with cilia
  • cells without cilia
  • goblet cells, and
  • basal cells
  • transient immune cells – lymphocytes and mast cells

The ciliated and non-ciliated cells help create most of the physical barrier as they form a tightly-connected sheet that lines the nasal cavity.  This “tight junction” that is formed between these cells, effectively keeps foreign materials – pollutants and microorganisms – from getting into our tissues and bloodstreams.  A breakdown in this barrier can be dangerous.

The goblet cells produce mucus – snot.  Nasal mucus, in the proper viscosity (thickness, stickiness) and amount, is the key to the system of mucociliary clearance working normally.  Mucociliary clearance is the holy grail for healthy sinuses.  Achieve this, you achieve respiratory health.


The most important feature of the respiratory epithelium, shown in the picture above, are the cilia.

Cilia of the ciliated epithelial cells work together to sweep out the mucus that contains any adherent foreign material, including microorganisms and pollutants.  In order to work normally, these cilia need a certain level of humidity.  They are also VERY sensitive to airborne pollutants.  These include toxins that are in cigarette smoke, in common air pollution, and various volatile organic compounds (VOC’s).  VOC’s are all around us in our synthesized, plasticized, man-made world.  They come out of our cleaning agents, out of adhesives, and out of all that plastic.  These toxins prevent the cilia from working properly.

If mucociliary clearance does not function, we can expect chronic respiratory illness, and life-threatening infections can result.  These cilia are on the respiratory epithelial cells that line the upper and lower respiratory tract, including the nose, the sinuses, and the middle ear, as well as the trachea and bronchioles.  The result can be rhinitis, sinusitis, otitis (ear infections), bronchitis, and pneumonia.

The basal cells are progenitor cells – baby cells – that will divide and grow to replace the other cell types when they grow old or are lost due to a toxic environment.  The immune response of the nasal epithelium helps us fight off attacks from various microorganisms (viruses, bacteria, mold), but if it goes haywire, can contribute to allergic rhinitis.

Immune Function:

Finally, the mucus contains special antibodies and enzymes that:

  • prevent viruses and bacteria from sticking to the epithelial lining
  • help our white blood cells to recognize viruses and bacteria as invaders and to kill them

Sorry for the dry, boring anatomy lesson, but it is important to have some idea of how the sinuses relate to the nose and rest of the upper airway.  It is important to have some understanding of how it all fits together and how it works if we are to succeed at keeping it all healthy.  This knowledge will help you as we move forward to control your child’s rhinitis and sinusitis, and improve their asthma or other chronic aero-digestive inflammatory disorders.  See you here again as we move toward that goal.  I will refer to this post often.  There will be a quiz next week ;-)

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Best health and success to you and your families.

It seems that some families of my former patients have found my blog and have left a couple very kind comments.  Thanks you so much! Please post a comment so that we can all learn to achieve sinus health, and healthy airways.  And please, “be excellent to one another.”

Until next time, remember … you can pick your friends, and you can pick your nose, but you can’t pick your friend’s nose (unless you’re a boogor doctor ;~D)


  1. Thank you for much for a wonderful, informative site with the added pleasure of a sense of humor!

    • Russell A. Faust, PhD, MD says:

      Hi Letitia,

      Thank you for your kind comments.
      I am grateful for your readership, and that you have taken the time to leave a comment.


  2. Elizabeth says:

    I am currently on antibiotics for sinusitis. Several days ago when my symptoms were at their worse, I tried sinus irrigation and my sinuses were totally blocked. The fluid, I think, went in my eustachian tubes and ever since, although my sinus symptoms have subsided, I have a totally blocked and a constantly crackling right ear. What do I do? Will it eventually go away? It’s been like it almost a week now.

    • Russell A. Faust, PhD, MD says:

      Hi Elizabeth,
      That is common. In fact, I get rinse up my eutstachian tube with every nasal/sinus rinse (oddly, only the right side). The fluid in the middle ear WILL make odd noises – crackles and pops – but should not cause any further problems. It should also dissipate within a week or so. Since I do nasal saline rinses every day, I commonly have some crackling and popping in my right ear, but it never becomes infected or painful. It is much less annoying than my chronic sinusitis was, so I continue the saline rinses and put up with it. I also find that it helps to use less force when I do the rinses, and mostly rinse the other side. The saline goes through both nasal airways, regardless, so I still get the benefits on both sides.
      Please let me know how this turns out for you.

  3. Hi Dr. Faust,

    I stumbled onto your website; very informative, thanks.

    Three basic questions: First, are all of the sinuses connected to one another? The reason for asking is that when I do nasal irrigation (after being in dusty/pollen situations) I have wondered if the irrigation flushes ALL of the sinuses or just the maxillary? My second question — some sites caution against using nasal irrigation if you have nasal polyps OR a deviated septum — I probably have a somewhat deviated septum, but nasal polyps? (How would one know, short of being scoped in the nasal area?) Should I still irrigate not knowing if I have nasal polyps?
    Finally, I do get transient dizziness around the same time I go on an irrigation campaign; the dizziness goes away, eventually. But I wonder; was the dizziness related to the allergies (ear involvement) or the use of the irrigation? Note: I use ONLY microwave-warmed distilled water along with the salt packets from Neil Medical under the most sterile conditions, following the neti-pot / irrigation process directions to the letter.

    Any thoughts?


    • Russell A. Faust, PhD, MD says:

      Hi Frank,
      The sinuses are all connected, in the sense that they all empty into the nasal cavity. When I think of nasal saline rinses, I think of rinsing the nose, not really rinsing the sinuses, since most of that saline does not actually make it into the sinuses. That’ okay though, because the area that you want to affect – to reduce swelling – is at the opening of the sinuses, not necessarily inside the sinuses. And: you want to rinse away all of the allergens, irritants, and particulate pollutants that collect in the nasal cavity (they stick to the mucus). So, nasal saline rinses help in a couple ways. They rinse away irritants; and they reduce swelling at the opening to the sinuses, allowing the sinuses to normally aerate.
      The dizzy symptom is a new one for me; should ask your ENT doc.
      Thanks for taking the time to share. Please keep me updated.

  4. says:

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  5. Awesome site you have here but I was curious about
    if you knew of any forums that cover the same topics discussed here?
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  6. Rebecca says:

    Every morning I wake up with you might call a “mucous plug” deep in my nostrils. The only way I can get it out is with my pinkie finger. The size and shape of it, as well as how it feels when I’m getting it out, tell me that the plug extends into both nostrils. It seems to wrap gently behind and on either side of the septum. Is this normal (it’s not painful, and it doesn’t impede my breathing). And does this mean my septum is perforated? Many thanks!

    • Russell A. Faust, PhD, MD says:

      Hi Rebecca,
      You might consider using a humidifier at night in your bedroom; also consider trying nasal saline rinses – I use the system (no financial relationship). That will provide excellent nasal hygiene by rinsing away things that irritate your nose – pollutants; cigarette smoke particles; allergens; etc. This is assuming that you don’t smoke tobacco; if you do – QUIT!
      Thank you for visiting and taking time to share.

      • Rebecca says:

        Thanks for your reply. I was actually trying to ask a specific question about nasal anatomy. Is it possible to have a single “boogor” stretching behind the nasal septum, with one end stretching into the left nostril and the other end stretching into the right nostril? Or should the nasal septum completely separate the nostrils? Thanks :)

        • Russell A. Faust, PhD, MD says:

          Hi Rebecca,
          What you describe may be a sino-nasal polyp. If you are experiencing what you describe, you should consider visiting with an Ear, Nose & Throat doc (otolaryngologist) for an exam. Best success.

  7. Hi Doctor,

    Thanks for such clear explanation of this stuff! That’s hard to find on the internet, sadly.

    I have kind of a weird issue that I was hoping you might be able to shed some light on. I get this feeling of fullness in my left ear and also sometimes in the right. When I speak, the sound of my voice sort of reverberates through my head from the inside and is very loud and distracting. When I yawn or move my jaw in a certain way I feel and hear this popping and cracking sound in my ears. I saw my family doc and had my ears irrigated and there is no blockage that is causing this from the outside of the ear. She sent me to an ENT who did some looking around and didn’t find anything, but did order a CT (I haven’t done that yet). They did a hearing test and I have no hearing loss.

    So here’s the weird part (please bear with me): I happen to do this exercise where I do a handstand against a wall, and when I do it (i.e., when I’m upside down) the condition goes away instantly and completely! Any ideas what might be causing this issue?

    About three years ago I had surgery for sleep apnea (turbinate reduction, tonsillectomy, he straitened my septum and took out some of my soft palate–with no complications, thank god.). This issue existed prior the surgery and I kind of assumed that it was related to my mild springtime allergies, but why would it go away when I’m upside down? I hope I don’t sound like a crazy person. It’s all true.


    • Russell A. Faust, PhD, MD says:

      Hey Joe,

      You MAY be crazy, but what you describe is common: eustachian-tube-dysfunction.
      Take a look online for more info, but here’s a good description from my friend, Dr. Chang:

      Let me know if you have questions after looking into this.
      Thanks for visiting, and please keep me updated!

  8. Dr. Faust,
    Since 2012 I started with my nose stopping up & eventually just went from bad to worse. I wake up with my nose stopped up then I start sneezing & then I have to start blowing my nose then the pain comes. Feels like someone has a blow torch up my left nostril. I have pain in my left eye. So much pressure & pain. Went to an ENT almost 2 years ago she did a Cr scan told me I had chronic sinusitis & a severely deviated septum. She said I needed surgery. I came up with the money to pay her but the hospital wanted to charge over 15,000 to do the surgery there. My family doctor gives me hydocodone for pain but it doesn’t help. We also have no insurance. My life is miserable & I’m in pain every day. I mean severe pain!!!!! I have a few side effects. When I blow my nose alot of snot comes out but it’s all clear as can be. I’m not sure when I can have surgery. Can you suggest something that will give me relief 😌??? I have been dealing with this for a long time. Thank you for your time. Sincerely, Carla

    • Russell A. Faust, PhD, MD says:

      Hi Carla,
      I’m so sorry but I have no way to help over the internet :(
      My best recommendation is to find a more holistic practitioner (ND?) and see if they can find underlying issues that can be corrected without surgery. Best success on your path to health and wholeness!

  9. Hello Dr. Faust,
    I’m so glad I came across your website! I have suffered with ear, nose and jaw problems my entire life and I am about to turn 47 in August. I had my tonsils and adenoids removed when I was 14 (due to always having breathing problems, sinus infections and strep throat). I have also suffered with a poor Immune System and enlarged spleen since I was 10 years old (my parents knew and prayed it was something that would just take care of itself). As the years have passed by I have watched my face keep changing (my chin has kept moving to the left of my face). When I was 28 years old I decided to have Rhinoplasty (not to actually straighten my nose, because the Doctor said it was nearly impossible with my facial structure), I had a small plastic square piece put into my chin (to try and at least show a little symmetry with my chin and my nose) and some fat was lipo-suctioned out of my neck. About 2 1/2 years ago I had a 3D scan done of my face through our local Orthodontist and he said I had an unusual cyst in my left sinus cavity and I should watch it. I saw our local ENT and he wasn’t to concerned about it, so neither was I. In the beginning of this year the left side of my face started aggravating me and so did my ear, but I wasn’t able to get into my Doctor @ the Clinic. I just kept messing with my face (rubbing it constantly…even though it hurt), using an ice pack as much as possible (even sleeping with one), different methods for my ear, etc..,
    One evening while watching television with my husband, I was rubbing my face and heard (also felt) something pop (hurt really bad😐). I knew at that moment something terrible had happened and just had no idea what?!?! I was up all night and gradually I watched (looking in the mirror frequently; not something I am very fond of at this stage in my life) and I took selfies of myself at different hours in the morning as my face changed shape. I couldn’t believe the transformation that I was watching. Wow! This was one of the scariest moments of my life (yes, vanity was out of control and all kinds of things were running through my mind…I actually thought I was going to die). My 15 year old son looked at me and said, “Mom, Are you going to look like that for the rest of your life? Could you die?” I truly didn’t know the answer to that question.
    I ended up having a really bad left staph ear infection and left sided facial Cellulitis. Could you possibly tell me how someone gets Cellulitis in the face? Am I doing something to cause it? Also, I live in a very small town in Wyoming and Doctors are limited. When I got out of the Hospital the ENT who saw me twice and I was supposed to see when I got out (actually had a scheduled appointment with him) called me the day of my appointment and had his assistant tell me he couldn’t help me and when I asked her why, she said that he said, “I can’t help that poor woman!”

    I still have sinus, ear, facial, jaw and other facial discomforts. Do you possibly know anyone that could help me? I suffer with a lot of health problems that started in 2007 with West Nile, Encephalitis and Fibromyalgia. The list just goes on…
    I am currently a young woman that is extremely frustrated, misses being a go-getter like she’s always been, misses a lot of family events and is watching the years fly by!!!

    I am Disabled, unable to work, sleep most of the days away, not really able to exercise due to the pain and have gained 30lbs since 2007.

    I’m no working on myself and starting from my head to my toes “literally!”

    Thank you for letting me vent…(even if this isn’t the right forum;)😊

    • Russell A. Faust, PhD, MD says:

      Hi Karla,

      Sounds frustrating! And the fact that you are asking for my opinion only reflects your level of desperation. My best advice: find a physician with a holistic approach – perhaps a Naturopathic Doctor (ND) – even if that means traveling to another state. Of course, there are very well-trained holistic physicians in California, though I know of many in other states. I’m sorry that I don’t have other recommendations beyond that: find a physician who will help educate you and who will listen (not in order), and who will work with you as a team. Thank you for sharing. Best success.

  10. Does many cilated epithelial cells seen in sinus gram stain indicate fungal growth/infection?

    • Russell A. Faust, PhD, MD says:

      No: epithelial cells are normally present in gram stain swabs from sinuses. It’s a positive sign that you have ciliated epithelial cells present.

  11. Hi Doctor,
    5 months ago I felt a fullness in my left ear. I used sinus rinse and after a day my nose was blocked and I wasn’t able to smell.Went to the ENT turned out that the fullness in my ear was fluid built in my ear. My turbinates were so inflammed and the ENT prescribed some antibiotics. A week later the fluid was gone. But It seemed that was having a severe sinus infection. It cleared after after a month. But since then I can’t smell or taste anymore. Is this about the fluid in my ear spreading the virus to my olfactory nerve via sinus rinse ? And if the fluid was viral how could antibiotics clear it out ? Can a sinus rinse spread a virus from ear to olfactory area?

    • Russell A. Faust, PhD, MD says:

      Hi Denise:

      Virus anywhere in the upper respiratory tract can affect you sense of smell: the olfactory sensory nerves are very sensitive. Saline nasal rinses are unlikely the cause of “spreading virus from your ear to your olfactory area,” but I suppose it’s possible. I have occasionally seen patients (or in my own personal experience) where a sinus infection seems to spread to an ear infection. That MAY have been related to saline rinse moving through an infected area (nasal passages) into the throat (where Eustachian tubes travel to the middle ear), but again: that ‘spread’ of infection may have occurred even if saline rinses were not being done.

      It is rare that loss of olfaction does not recover. Sense of smell usually recovers within a few weeks following the injury done by viral infection.

      Hoping that you sense of smell recovers!
      Thanks so much for visiting, and especially for taking time to share.
      Please keep me updated.

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