|It is always a good idea to learn the bones of a region before proceeding
further. The bones of the nasal septum and other landmarks are:
|The skeleton of the lateral nasal wall include:
|Usually when the head is bisected, the nasal septum is either destroyed
or left behind on one side.
The nasal septum is made up of the following:
|The septum and the nasal cavity, in general is highly vascularized.
One reason for this might be to warm the air before it reached the bronchi
and lungs. The major arteries of the septum are:
|Sensory innervation to the nose is also important in that it provides
reflexes (such as the sneeze reflex) to keep foreign particles out of the
respiratory system. The sensory nerves to the septum are:
|Be sure you know which is front and back and up and down. Look at the
lateral wall of the nasal cavity and identify:
The superior and middle conchae are parts of the ethmoid bone.
The inferior concha is a separate bone of the skull.
|Once the most obvious structures are identified, removal of the middle
and inferior conchae reveals other items to be identified:
|In order to get an idea as to the relationship of the nasal cavity
to the air sinuses, a frontal section is shown in the image. Again use
familiar structures to orient yourself, like the orbits with the optic
foramen (black circle). Identify:
Also note that the floor of the nasal cavity is made up of the palatine processes of the maxilla (6).
|The paranasal sinuses are lined with a mucous membrane that secretes
a fluid to keep the lining moist. Under normal conditions, the sinuses
drain into various parts of the nasal cavity.
You should also realize that when the drainage pores are closed off due to irritation, the mucous can no longer drain out of the sinuses, they fill up and cause pressure which can then cause headaches (sinus headaches).
Sinus medication reduces the swelling so that the mucous can drain.
|Continuing to work you way laterally, you can remove the bone further and open up the maxillary sinus. You can also see the nasopalatine nerve (1) emerging through the sphenopalatine foramen. Once the foramen is identified, you can then see a small bulge formed by the bony greater palatine canal. If this is broken down, you would see the greater palatine nerve and artery in the canal.|
|After more of the lateral nasal wall has been removed, you can see
the major nerve coming into this region, the maxillary division of the
|As you go posterior to the inferior concha, you enter the nasopharynx.
The roof is the body of the sphenoid, the floor is the soft palate and
it is open to nasal cavity anteriorly and pharynx posteriorly. When the
mucous membrane is carefully removed, you can see the small muscles of
the soft palate and upper pharynx. Landmarks are the tubal elevation (torus
tubarius) and the uvula (u).
The muscles are:
The palato- and salpingopharyngeus muscles join the stylopharyngeus to form the longitudinal muscles of the pharynx. The help elevate the pharynx when you swallow.
|The major sensory innervation to the nasal cavity is from branches of the maxillary division of the trigeminal (nasopalatine, infraorbital, greater palatine). Other sensory branches are from the ophthalmic division (anterior ethmoidal nerve). Any secretory glands of the nasal cavity are supplied by branches of the pterygopalatine ganglion. The olfactory epithelium in the roof of the nasal cavity is innervated by the olfactory nerve (I) and receives smell sensations.|
|The major arterial supply to the nasal cavity are from the ophthalmic and maxillary arteries by way of anterior and posterior ethmoidal branches and sphenopalatine branches respectively.|
|tensor palati||scaphoid fossa of pterygoid fossa||aponeurosis of soft palate||elevates and tenses soft palate||V3|
|levator palati||apex of petrous temporal bone and auditory tube||aponeurosis of soft palate||pulls soft palate up and back||X|
|palatopharyngeus||aponeurosis of soft palate||wall of pharynx||elevates pharynx||X|
|salpingopharyngeus||cartilage of auditory tube||wall of pharynx||elevates pharynx||X|
|Pharynx||Oral Cavity & Paranasal Sinuses|
|Copyright© 1999 by Wesley Norman, PhD, DSc|