Nasal Septum and Nasal Wall Vascularization

Introduction


The nasal cavity has a rich vascular network. Arteries that supply the nasal septum and the lateral nasal wall include vessels originating from the external carotid artery (maxillary and facial artery) and from the internal carotid artery (ophthalmic artery).


3.2 Branches of Maxillary Artery (Arteria Maxillaris)


The maxillary artery (MA) is one of the two main end arteries from of the external carotid artery. It is located behind the neck of the mandible and passes lateral or medial to the lateral pterygoid muscle to reach the pterygopalatine fossa (PF) through the pterygopalatine fissure (pterygopalatine segment) ( ▶ Fig. 3.1). In the PF, the MA and its branches are located anteriorly to the neural elements. Through the PF different branches supply the orbit, the nasal cavity, the nasopharynx, the cavernous sinus, and the carotid canal. In some cases branches of the first segment of the MA (mandibular segment) can supply the nasopharynx through their extracranial branches (the middle meningeal artery and accessory meningeal artery).



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Fig. 3.1 Axial computed tomography angiography with maximum intensity projection: the maxillary artery crosses lateral (a) and medial (b) to the lateral pterygoid muscle (*).


3.2.1 Sphenopalatine Artery (Arteria Sphenopalatina)


It is the terminal branch of the MA that emerges from the superomedial part of the PF and enters the nasal cavity through the sphenopalatine foramen. This foramen is usually located in the superior meatus, although it may also be found in the middle meatus or at the transition of both meatuses, according to its location above or below the ethmoidal crest. This anatomic landmark is an optimal bone reference to localize the sphenopalatine artery because it is just posterior to this crest ( ▶ Fig. 3.2).



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Fig. 3.2 The ethmoidal crest (EC) in the left nasal cavity. The two main branches of the sphenopalatine artery are posterior to this crest. MT, middle turbinate.


It gives off two main branches, the posterior lateral nasal artery (PLNA) and the posterior septal artery (PSA), 1,​ 2 which can be divided into one or two trunks medial to the ethmoidal crest, before or after crossing the sphenopalatine foramen. It is rarely possible to identify more than two trunks. 1,​ 3 The PLNA supplies the region of the lateral nasal wall giving off branches to the inferior turbinate (inferior turbinate artery), middle turbinate (middle turbinate artery), mucosa of the fontanelle, and to the mucosa of the maxillary sinus 4 ( ▶ Fig. 3.3, ▶ Fig. 3.4). In approximately 20% of cases this artery supplies the superior turbinate. 5 The inferior turbinate artery enters a bony canal and runs anteriorly along the turbinate. It usually gives off two terminal branches, within or adjacent to the bone, supplying the mucosa of the turbinate ( ▶ Fig. 3.5). The artery gives off several small vessels to the maxillary sinus and to the ethmoidal complex. The middle turbinate artery gives off several branches, some of which run along the medial surface of the turbinate whereas the other branches supply the lateral turbinate surface and anterior ethmoidal complex (see ▶ Fig. 3.3).



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Fig. 3.3 The posterior lateral nasal artery in the left nasal cavity gives off the inferior turbinate (IT) artery (*) and middle turbinate (MT) artery (**). MS, maxillary sinus.



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Fig. 3.4 The posterior lateral nasal artery in the left nasal cavity gives off branches to the mucosa of the fontanelle and maxillary sinus (MS) (*). IT, inferior turbinate; MT, middle turbinate.



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Fig. 3.5 Two terminal branches along the inferior turbinate in the left nasal cavity. AF, accessory foramen; IT, inferior turbinate; MS, maxillary sinus; MT, middle turbinate; PLNA, posterior lateral nasal artery.


The PSA crosses the anterior wall of the sphenoid sinus in a subperiosteal plane, between the choana and sphenoidal ostium. In most cases the artery bifurcates into the superior and inferior branches ( ▶ Fig. 3.6). In this area it supplies the superior turbinate (superior turbinate artery), sphenoid sinus, and posterior ethmoid complex. The superior turbinate artery can arise from the superior division of the PSA or directly from the trunk of the PSA. 6 The PSA branches on the nasal septum irrigating the inferior two-thirds. The distal extreme of the inferior branch of the PSA, the nasopalatine artery, vascularizes the inferior septal area and ends in the incisive canal where it anastomoses with the greater palatine artery (GPA). 1,​ 2 Furthermore, the PSA presents anastomosis in the septal area with the ethmoidal arteries and with branches from the SLA ( ▶ Fig. 3.7).



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Fig. 3.6 The posterior septal artery (PSA) crosses between the choana and the sphenoidal ostium (SO) in the left nasal cavity. The artery bifurcates into superior and inferior branches. MT, middle turbinate.



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Fig. 3.7 Nasal septum vascularization. AEA, anterior ethmoidal artery; NPA, nasopalatine artery; PEA, posterior ethmoidal artery; SLA, superior labial artery.


3.2.2 Posterior Superior Alveolar Artery (Arteria Alveolaris Superior Posterior)


The posterior superior alveolar artery (PSAA) usually represents the first branch of the pterygopalatine segment of the MA. It runs close to the periosteum of the convexity of the maxillary tuberosity and divides into two branches: a lateral descending vessel (dental branch) and an internal vessel (peridental branch). This internal branch perforates the tuberosity of the maxilla and courses endosseously supplying the mucosa of the maxillary sinus and anastomosing with the IOA 2,​ 4,​ 7 ( ▶ Fig. 3.8).



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Fig. 3.8 Sagittal computed tomography angiography with maximum intensity projection. The infraorbital artery (IOA) runs along the roof of the maxillary sinus and the posterior superior alveolar artery (PSAA) courses in the lateral wall of the maxillary sinus.


3.2.3 Infraorbital Artery (Arteria Infraorbitalis)


The infraorbital artery (IOA) originates from the MA or from a common trunk with the PSAA. The artery enters the maxillary sinus through the inferior orbital fissure. It runs into the infraorbital groove, which then becomes an infraorbital canal and emerges through the infraorbital foramen (see ▶ Fig. 3.8). Through a wide middle antrostomy or through an accessory ostium, we can observe the artery running anterolaterally in the roof of the maxillary sinus ( ▶ Fig. 3.9). Within the infraorbital canal, it gives off branches to the mucosa of the roof, the medial and anterior wall of the maxillary sinus (anterior superior alveolar arteries). At the infraorbital foramen it can anastomose with the SLA and the dorsal nasal artery (terminal branch of the ophthalmic artery). 4,​ 7,​ 8,​ 9



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Fig. 3.9 The infraorbital canal seen through a middle meatal antrostomy.

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Nov 27, 2018 | Posted by in OTOLARYNGOLOGY | Comments Off on Nasal Septum and Nasal Wall Vascularization
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