Nasal Cavity PDF

Nasal Cavity DPM Program Learning Objectives: 1. Describe the nasal cavity. 3.0 2. Describe the paranasal sinuses and their innervations. 3.0 3. Describe the pterygopalatine fossa and its contents. 3.0 4. Describe the major arteries that supply the lateral wall and nasal septum in relation to nosebl...

Nasal Cavity DPM Program Learning Objectives: 1. Describe the nasal cavity. 3.0 2. Describe the paranasal sinuses and their innervations. 3.0 3. Describe the pterygopalatine fossa and its contents. 3.0 4. Describe the major arteries that supply the lateral wall and nasal septum in relation to nosebleeds. 3.0 1 The Paranasal Sinuses Paired and found in the frontal, maxillary, ethmoid, and sphenoid bones. -Normally filled with air -Mucousa is innervated by branches of the trigeminal nerve -Function to provide vocal resonance, lighten the skull bones, and increase surface area of the nasal mucosa for air conditioning 2 Osteology 3 The Nasal Cavity The nasal cavities open to the outside through the nostrils or anterior nares and open to the nasopharynx through the CHOANAE. The mucous membrane lining the nasal cavity is divided into an OLFACTORY AREA in the upper 1/3 and a RESPIRATORY AREA in the lower 2/3. VESTIBULE: entrance to the nasal cavity. Nasal cavity divided into two parts by the NASAL SEPTUM: 1) Perpendicular plate of the Ethmoid bone 2) Vomer 3) Septal Cartilage CONCHAE: -Found on the lateral wall of the nasal cavity. -Purpose is to increase the surface area for conditioning inspired air -INFERIOR, MIDDLE, SUPERIOR, & SUPREME CONCHAE MEATUS: -the space inferior and lateral to each concha is called a meatus INFERIOR MEATUS: inferior to inferior concha; nasolacrimal duct drains here MIDDLE MEATUS: inferior to middle concha; anterior & middle ethmoid air cells, the maxillary sinus,& frontal sinus drain here. Also contains the ETHMOIDAL BULLA. SUPERIOR MEATUS: inferior to superior concha. Posterior ethmoid air cells drain here. The space above and posterior to the superior concha is called the SPHENOETHMOIDAL RECESS. Sphenoidal sinus drains here. 4 5 6 Neurovasculature of the Nasal Cavity BLOOD SUPPLY Anterosuperior – primarily from Ophthalmic a. - e.g., branches of nasociliary a. Posteroinferior– primarily from Maxillary a. - e.g., sphenopalatine a. to nasal septum INNERVATION Anterosuperior – (Ophthalmic n. V1) - e.g., branches of nasociliary Posteroinferior– (Maxillary n. V2) - e.g., nasopalatine n. to nasal septum KIESSELBACH’S AREA where 5 arteries anastomose on the anterior aspect of the nasal septum. Where most nose bleeds occur Note: arteries to the lateral nasal wall do not contribute to the blood supply in Kiesselbach’s area, however, they do arise from the maxillary, ophthalmic and facial arteries (to the nasal vestibule). 7 The Pterygopalatine Fossa The pterygopalatine fossa is a relatively small space, shaped like an upside-down pyramid, and situated between the pterygoid process of the sphenoid bone and the posterior aspect of the maxilla. The importance of the pterygopalatine fossa is that it serves as a ̳distribution center‘ for the following: -Maxillary division of trigeminal nerve -Parasympathetic fibers from the Facial Nerve -Sympathetic fibers from the Superior Cervical Ganglion -Terminal Branches of the Maxillary Artery 8 Maxillary Artery in the Pterygopalatine Fossa While in the parotid gland, the external carotid artery ends by bifurcating into the (superficial temporal a. – to the scalp) and the maxillary artery. - The maxillary a. travels through the infratemporal fossa where it supplies the mm. of mastication, dentition, and gives off the middle meningeal a. - The maxillary a. then enters the pterygopalatine fossa where it gives off branches to the palate, nasopharynx and poster inferior aspect of the nasal cavity. 9 Maxillary Nerve in the Pterygopalatine Fossa The Maxillary nerve gives off GSA branches to: - the dermatome of the face (e.g. infraorbital nerve) - nasopharynx - hard & soft palates (greater/ lesser palatine nn.) - posteroinferior nasal cavity (e.g. nasopalatine) - upper dentition (superior alveolar nn.) The pterygopalatine (GVEp) ganglion is suspended from The Maxillary division of Trigeminal (V2) in the pterygopalatine fossa. Postsynaptics hitchhike on branches of V2 to reach their targets 10