Nasal and Sinus Anatomy (and Histology)

ANATOMY:

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

Turbinates:

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)

Adenoids:

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.

HISTOLOGY:

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.

Cilia:

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 ;-)

For a free download of this article in PDF format, go to the download page here: http://wp.me/PR4iB-s7

If this blog is helpful for you, please click here to subscribe for free email updates (did I mention it’s FREE):

Simply type your best email address (the one you actually use) into the orange-outlined box at the upper right of the page, and click the subscribe button. When you receive the confirmation email, click on the link to give your okay to receive weekly email updates.

No advertising, no spam.  It’s easy, it’s convenient, it’s free. You can un-subscribe any time.

Stay informed, stay healthy.

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)

Comments

  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.

      RF

  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.
      RF

  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?

    Frank

    • 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. http://stage4bonecancer.tumblr.com/post/52530912969/bone-cancer-survival-rate says:

    Good post. I learn something new and challenging on sites I stumbleupon
    every day. It will always be helpful to read content from other authors and use
    something from their web sites.

  5. Awesome site you have here but I was curious about
    if you knew of any forums that cover the same topics discussed here?
    I’d really love to be a part of group where I can get feedback from other knowledgeable people that share
    the same interest. If you have any suggestions, please let me know.
    Cheers!

  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 Nasopure.com 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.

Trackbacks

  1. […] time. And the several pairs of sinuses grow at different rates. Here are the articles that review the anatomy and histology of the nose and sinuses, and development of the sinuses in children. For those of you who don’t want to wade through a […]

Speak Your Mind

*

Hide me
Sign up below to receive FREE email updates
Email Address
Show me
Build an optin email list in WordPress [Free Software]