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9. Describe the innervation and vasculature of the nasal cavity.
9. Describe the innervation and vasculature of the nasal cavity.
Nasal septum (medial wall of nasal cavity):
The nasal septum receives vasculature from three general sources:
superiorly, from the anterior ethmoidal a. (via anterior septal brs.) and the posterior ethmoidal a.,
posteriorly from the sphenopalatine a. (via posterior septal brs.), and
anteriorly from the superior labial a. (via nasal septal brs.) and greater palatine a.
These arteries come from the ophthalmic a. (anterior & posterior ethmoidal aa.), maxillary a. (sphenopalatine & greater palatine aa.), and the facial a. (superior labial a.). The arteries of the nasal septum anastomose on the anterior aspect of the septum, and area known as the Kiesselbach’s area/plexus. A preponderance (>90%) of episodes of epistaxis (‘nose bleed’) originate in Kiesselbach’s area.
The nasal septum is innervated by branches of V1 and V2.
V1 supplies the septum through:
medial nasal brs. (from internal nasal brs. of the anterior ethmoidal n.), whereas
V2 supplies the septum through:
nasopalatine n., and the
posterior superior medial nasal brs.
Most of the nasal septum is innervated by nasopalatine n. A small part of the nasal roof and superior portion of the septum is innervated by the posterior superior medial nasal brs. The anterior portion of the nasal septum is innervated by medial nasal brs. (of internal nasal brs. of the anterior ethmoidal n.).
One of the more obvious contributions of neurovasculature to the nasal septum is the collection of olfactory nn. (CN I). The olfactory nn. can be located descending inferiorly from the cribriform foramina of the ethmoid bone.
Lateral wall of nasal cavity:
The lateral nasal wall is served by branches of the same arteries which serve the nasal septum, namely the:
anterior ethmoidal (via anterior lateral nasal brs.) & posterior ethmoidal aa.,
sphenopalatine a. (via posterior lateral nasal aa.), and the
facial a. (via lateral nasal br.).
The lateral nasal wall is innervated by branches of V1 and V2 that also serve the nasal septum.
V1 supplies the lateral wall through:
lateral nasal brs. (from internal nasal brs. of the anterior ethmoidal n.), whereas
V2 supplies the lateral wall through:
posterior superior lateral nasal brs.,
posterior inferior lateral nasal brs. (from greater palatine n.),
nasal brs. of the anterior superior alveolar n., and
internal nasal br. of the infra-orbital n.
The mid- to posterior aspects of the lateral nasal wall are innervated by posterior superior lateral nasal brs. and posterior inferior lateral nasal brs. (from greater palatine n.). Posterior superior lateral nasal brs. innervate the superior and middle nasal meatuses, whereas the posterior inferior lateral nasal brs. innervate the middle and inferior nasal meatuses. The anterior aspect of the lateral wall is innervated superiorly by lateral nasal brs. (from internal nasal brs. of the anterior ethmoidal n.) and inferiorly by nasal brs. (of the anterior superior alveolar n.) and internal nasal brs. (of the infra-orbital n.).
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