Nasal Cavity and Paranasal Sinuses Flashcards
Name the paranasal sinuses and air cells (6), where they directly open to, and which branch of trigeminal innnervates them.
Maxillary sinus - opens to semilunar hiatus and innervated by CN V2
Frontal sinus - opens to semilunar hiatus via frontonasal duct and innervated by CN V1
Sphenoid sinus - opens to sphenoethmoidal recess and is innervated by CN V2
Anterior ethmoidal air cells - open to the semilunar hiatus and innervated by CN V1
Middle ethmoidal air cell - opens to ethmoidal bulla and innervated by CN V1
Posterior ethmoidal air cell - opens to superior nasal meatus and innervated by CN V1
What are complications of sinusitis?
Spread of infection to eye, CN II, brain, meninges, and teeth.
Note: Transillumination can be utilized to assess fluid levels in the sinuses
Why is the maxillary sinus susceptible to infection?
This sinus is susceptible due to the drainage pattern it exhibits.
Note: Infections can spread from the maxillary teeth to the maxillary sinus
Describe the drainage of the sinuses (nasolacrimal duct, maxillary, frontal, ethmoid, and sphenoid)
The nasolacrimal duct drains to the inferior nasal meatus. The maxillary sinus drains to the middle nasal meatus via the semilunar hiatus. The frontal sinus drains through the frontonasal duct to the semilunar hiatus and eventually the middle nasal meatus. The anterior ethmoidal air cells drain to the semilunar hiatus and middle nasal meatus. The middle ethmoidal air cells drain to the ethmoid bulla and then middle nasal meatus. The posterior ethmoidal air cells drain to the superior nasal meatus. The sphenoid sinus drains to the superior nasal meatus via the sphenoethmoidal recess.
Describe the course and branches of the anterior/posterior ethmoidal aa. in supplying the nasal cavity.
Ant./Post. ethmoidal arteries are branches of the ophthalmic a. They enter the nasal cavity by descending through the ethmoidal sinuses. They also supply blood to the ethmoidal sinuses.
Anterior ethmoidal artery provides ant. lat. and ant. septal nasal aa. to the nasal cavity and an external nasal artery to the dorsum of the nose.
Posterior ethmoidal artery provides lateral and septal nasal arteries.
Describe the course and branches of the sphenopalatine artery in supplying the nasal cavity.
The sphenopalatine artery traverses the sphenopalatine foramen to enter the nasal cavity. Here it gives rise to the post. lat. nasal and post. septal aa.
Describe the course and branches of the greater palatine a. in supplying the nasal cavity.
After coursing along the inferior surface of the palate the greater palatine a. enters the nasal cavity through the incisive canal. Here it provides nasal septal branches.
Describe how the facial artery provides blood to the nasal cavity.
The superior labial branch of the facial a. provides septal branches to the most anterior portion of the septum
What is the Kiesselbach area?
This is the area of anastomosis of the anterior ethmoidal, greater palatine, superior labial, and sphenopalatine aa. on the anterior septum.
Where do the fibers of CN I synapse?
In the forebrain, specifically the olfactory bulb.
Where are the bipolar neurons associated with CN I located?
Olfactory epithelium
Specifically describe the GSA innervation of the nasal cavity and paranasal sinuses provided by CN V1 (4 branches)
supraorbital and supratrochlear nn. provide GSA innervation to the frontal sinus
Posterior ethmoidal n. provides GSA to the ethmoid sinus
Anterior ethmoidal n. provides GSA to the ethmoid sinus. Ant. lateral nasal and septal nn. and external nasal n.
Describe the GSA innervation of the nasal cavity and paranasal sinuses provided by CN V2 (6 branches)
Infraorbital n - maxillary sinus and lateral nose
Posterior superior alveolar n. - maxillary sinus
Nasopalatine n. - enters the nasal cavity through the sphenopalatine foramen and provides innervation to the nasal septum
Pharyngeal n. - ascends to the sphenoid sinus
Post. sup. lat. nasal n. - enters the nasal cavity through the sphenopalatine foramen and innervates most of the sup. lat. nasal wall
Post. inf. lat. nasal n. - enters the nasal cavity through an unamed foramen as a branch of greater palatine n. and innervates most of the inf. lat. nasal wall
Describe the parasympathetic innervation of the nasal cavity.
Preganglionic cell bodies lie in the salivatory nucleus and their fibers run with CN VII and follow the greater petrosal nerve from the middle ear. In the middle cranial fossa the greater petrosal n. joins the deep petrosal n. to form the vidian n. This will synapse at the pterygopalatine ganglion. Fiber project from here along CN V2 to the nasal cavity and paranasal sinuses.
Describe the sympathetic innervation of the nasal cavity
Preganglionic cell bodies lie in the lateral horn of spinal segments T1-4. These fibers ascend the sympathetic chain to synapse at the superior cervical sympathetic ganglion. From here fibers run with the deep petrosal n. to piggy-back on branches of CN V2 to the nasal cavity and paranasal sinuses.
