question: why does only one nostril get plugged up when you have a “stuffy nose”
comment: [“Why Is Only Half of My Nose Working?” by SciShow]( URL_0 ) Relevant Tl;dr: it is always like that but it is more noticeable when you have a stuffy nose.
passages: In 1927, Heetderks described the alternating turgescence of the inferior turbinates in 80% of a normal population. According to Heetderks, the cycle is the result of alternating congestion and decongestion of the nasal conchae or turbinates, predominantly the inferior turbinates, which are by far the largest of the turbinates in each nasal fossa. Turbinates consist of bony projections covered by erectile tissue, much like the tissues of the penis and clitoris. The turbinates in one fossa fill up with blood while the opposite turbinates decongest by shunting blood away. This cycle, which is controlled by the autonomic nervous system as described above, has a mean duration of two and a half hours. He further observed and documented that the turbinates in the dependent nasal fossa fill when the patient is in the lateral decubitus (lying down on your side) position. Some postulate that this alternating positional obstruction has the purpose of causing a person to turn from one side to the other while sleeping in order to prevent bedsores. Others note that the asymmetric airflow may have some benefit to overall olfactory sensitivity. The nasal cycle is an alternating one, with the total resistance in the nose remaining constant. In patients with a fixed septal deviation and intermittent nasal obstruction, the interplay of the nasal cycle becomes evident; the sensation of obstruction frequently mirrors the congestion phase.
   There are two possible options for access to the sphenoidal sinus, including of endonasal approach (through the nostril) or sublabial approach (through an incision under the upper lip); many factors such as the size of nostril, the size of the lesion, and the preferences of the surgeon cause the selection of one access route over the other.
   Some odor chemicals bind with olfactory receptors easily, even under conditions of high airflow, and other odors need more time, under low airflow conditions, to bind with receptors. With high airflow on one side and low airflow on the other side, the olfactory center detects a greater range of smells.
  
  Section::::Distinction.
  
  The nasal cycle should not be confused with pathological nasal congestion: individuals with normal nasal breathing usually do not realize their breathing is asymmetric unless there is underlying nasal obstruction. In pathological conditions, however, the nasal cycle may influence the symptoms.
  
  Section::::Research on the effects.
   It has been shown that the cilia of the congested side suspend their motility until that side decongests. Thus the cycle ensures that one side of the nose is always moist, to facilitate humidification, which is one of the three functions of the nose, the other two being filtration and warming of inspired air prior to its entering the lungs.
  
  Section::::Benefits in olfaction.
   Section::::Distribution.
   In the most primitive living vertebrates, the lampreys and hagfish, there is only one nostril and olfactory pouch. Indeed, the nostril also opens into the hypophysis. This is not necessarily, however, a primitive trait, but one that may have arisen later in the evolution of these particular groups. For example, the fossil heterostracans had paired nostrils, and these were also a very early vertebrate group.
  
  Section::::See also.
  
  BULLET::::- Human nose
  
  BULLET::::- Nasal bridge
  
  BULLET::::- Rhinarium, the wet, naked surface around the nostrils in most mammals, absent in haplorrhine primates such as humans
   A common anatomic variant is an air-filled cavity within a concha known as a concha bullosa. In rare cases a polyp can form inside a bullosa. Usually a concha bullosa is small and without symptoms but when large can cause obstruction to sinus drainage.
   The "middle conchae" are smaller. In humans, they are usually as long as the little finger. They project downwards over the openings of the maxillary and anterior and middle ethmoid sinuses, and act as buffers to protect the sinuses from coming in direct contact with pressurized nasal airflow. Most inhaled airflow travels between the inferior concha and the middle meatus.
  
  The "inferior conchae" are the largest, and can be as long as the index finger in humans, and are responsible for the majority of airflow direction, humidification, heating, and filtering of air inhaled through the nose.
   The superior conchae completely cover and protect the nerve axons piercing through the cribriform plate (a porous bone plate that separates the nose from the brain) into the nose. Some areas of the middle conchae are also innervated by the olfactory bulb. All three pairs of conchae are innervated by pain and temperature receptors, via the trigeminal nerve (or, the fifth cranial nerve). Research has shown that there is a strong connection between these nerve endings and activation of the olfactory receptors, but science has yet to fully explain this interaction.
  
  Section::::Clinical significance.
  
  Section::::Clinical significance.:Dysfunction.
   There is a reinforcing structure known as the nasal scroll that resists internal collapse from airflow pressure generated by normal breathing. This structure is formed by the junction between the lateral and major cartilages. Their edges interlock by one scrolling upwards and one scrolling inwards.
  
  Section::::Structure.:External nose.
  
  The nasal root is the top of the nose that attaches the nose to the forehead. The nasal root is above the bridge and below the glabella, forming an indentation known as the nasion at the frontonasal suture where the frontal bone meets the nasal bones.
   On the lateral wall of each cavity are three shell-like bones called conchae, arranged as superior, middle and inferior nasal conchae. The conchae are also known as "turbinates." Below each concha is a corresponding superior, middle, and inferior nasal meatus, or passage. Sometimes when the superior concha is narrow, a fourth supreme nasal concha is present situated above and sharing the space with the superior concha. The conchae extend along the length of the nasal cavity.
  
  Section::::Structure.:Internal nose.:Roof of cavity.
   The internal nasal valve comprises the area bounded by the upper lateral-cartilage, the septum, the nasal floor, and the anterior head of the inferior turbinate. In the narrow (leptorrhine) nose, this is the narrowest portion of the nasal airway. Generally, this area requires an angle greater than 15 degrees for unobstructed breathing; for the correction of such narrowness, the width of the nasal valve can be increased with spreader grafts and flaring sutures.
  
  Section::::Nasal analysis.
   Section::::Nerve supply.:Parasympathetic supply.
   At the back of the nasal cavity there are two openings, one from each fossa, called choanae. The choanae are also called the posterior nostrils and give entrance to the nasopharynx and rest of the respiratory tract.
  
  Section::::Structure.:Internal nose.:Nasal valves.
   Nasal cycle
  
  The nasal cycle is the often unnoticed alternating partial congestion and decongestion of the nasal cavities in humans and other animals. It is a physiological congestion of the nasal conchae, also called the nasal turbinates, due to selective activation of one half of the autonomic nervous system by the hypothalamus. It should not be confused with pathological nasal congestion. The nasal cycle was studied and discussed in the ancient yoga literature of pranayama. In the modern western literature, it was first described by the German physician Richard Kayser in 1895.
  
  Section::::Description.
   It is possible that the nasal cycle may exacerbate the nasal congestion caused by the common cold, as the lack of motility of the cilia in one half of the nose may lead to an uncomfortable sensation of not being able to shift mucus by blowing the nose.
  
  Section::::Benefits in breathing.
   The nostrils are separated by the septum. The nostrils are a premature set of wings; those who are still able to flair said nostrils are known to be slightly less mature in the process of evolution. The septum can sometimes be deviated, causing one nostril to appear larger than the other. With extreme damage to the septum and columella, the two nostrils are no longer separated and form a single larger external opening.
   Badly positioned alar cartilages lack proper support, and can affect the function of the external nasal valve. This can cause breathing problems particularly during deep inhalation. The surgical procedure to correct breathing problems due to disorders in the nasal structures is called a rhinoplasty, and this is also the procedure used for a cosmetic surgery when it is commonly called a "nose job". For surgical procedures of rhinoplasty, the nose is mapped out into a number of subunits and segments. This uses nine "aesthetic nasal subunits" and six "aesthetic nasal segments". A septoplasty is the specific surgery to correct a nasal septum deviation.
   The sphenoid sinuses are extensions of the ethmoid sinuses into the sphenoid bones. They appear in the fifth month of life and continue to enlarge during childhood. The frontal sinuses develop in the fifth or sixth year of childhood a of the middle meatus.nd continue expanding throughout adolescence. Each frontal sinus is made up of two independent spaces that develop from two different sources; one from the expansion of ethmoid sinuses into frontal bone, and the other develops from invagination. They never coalesce so drain independently.
  
  Section::::Function.
  
  Section::::Function.:Respiration.
   The nasal septum can depart from the centre line of the nose in a condition that is known as a deviated septum caused by trauma. However, it is normal to have a slight deviation to one side. The septum generally stays in the midline until about the age of seven, at which point it will frequently deviate to the right. An operation to straighten the nasal septum is known as a septoplasty.
   Nostril
  
  A nostril (or naris , plural "nares" ) is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation. Fish do not breathe through their noses, but they do have two small holes used for smelling, which may, indeed, be called nostrils.
  
  In humans, the nasal cycle is the normal ultradian cycle of each nostril's blood vessels becoming engorged in swelling, then shrinking.
   There is a nasal valve area in the cavity responsible for providing resistance to the flow of air. This enables an increased time for warming and moistening the air. This area is of two nasal valves. The internal nasal valve is the narrowest part of the airway in the middle third of the cavity. The larger external nasal valve is located in the alar wall.
  
  Section::::Structure.:Internal nose.:Nasal vestibule.
   These nerves, with the exception of CN V, pass through the cavernous sinus to enter the orbital apex through the superior orbital fissure. The maxillary nerve, division V of the trigeminal nerve travels through the lower portion of the sinus and exits via the foramen rotundum. The maxillary branch passes external to, but immediately adjacent to, the lateral wall of the sinus)
  
  A mnemonic exists to remember the orientation of the vertical and horizontal content of the sinus: O TOM CAT. (OTOM are the lateral wall contents from superior to inferior; CAT are the horizontal contents from medial to lateral)
   The conchae comprise most of the mucosal tissue of the nose and are required for functional respiration. They are enriched with airflow pressure and temperature-sensing nerve receptors (linked to the trigeminal nerve route, the fifth cranial nerve), allowing for tremendous erectile capabilities of nasal congestion and decongestion, in response to the weather conditions and changing needs of the body. In addition, the erectile tissue undergoes an often unnoticed cycle of partial congestion and decongestion called the nasal cycle. The flow of blood to the nasal mucosa in particular the venous plexus of the conchae is regulated by the pterygopalatine ganglion and heats or cools the air in the nose.
   Nasal septum
  
  The nasal septum () separates the left and right airways in the nose, dividing the two nostrils.
  
  It is depressed by the depressor septi nasi muscle.
  
  Section::::Structure.
  
  The fleshy external end of the nasal septum is called the columella or columella nasi, and is made up of cartilage and soft tissue. The nasal septum contains bone and hyaline cartilage. It is normally about 2 mm thick.
  
  The nasal septum is composed of four structures:
  
  BULLET::::- perpendicular plate of ethmoid bone
  
  BULLET::::- vomer bone
  
  BULLET::::- septal nasal cartilage
  
  BULLET::::- maxillary crest
  
presuppositions: Only one nostril gets plugged up. Only one nostril gets plugged up when someone has a stuffy nose.
corrections: Both nostrils are always at different levels of openness and when you are stuffy it is exagerated. One nostril is always plugged up, but this is only noticeable when someone has a stuffy nose.
raw_presuppositions: Only one nostril gets plugged up. Only one nostril gets plugged up when someone has a stuffy nose.
raw_corrections: Both nostrils are always at different levels of openness and when you are stuffy it is exagerated. One nostril is always plugged up, but this is only noticeable when someone has a stuffy nose.