Pharynx, Larynx, Nasal Cavity and Pterygopalatine Fossa
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Pharynx, Larynx, Nasal cavity And Pterygopalatine Fossa Mikel H. Snow, Ph.D. Dental Anatomy [email protected] July 29, 2018 Pharynx Food & Air Passage Pharynx The pharynx is a skeletal muscle tube that opens anteriorly with 3 regions. The upper part communicates with nasal cavity, the middle communicates with oral cavity, and the lower communicates with the larynx. Nasal cavity Nasal Oral cavity cavity Larynx Air Nasopharynx: between Oral sphenoid sinus & uvula Food/ cavity Oropharynx: between uvula & epiglottis drink Laryngopharynx: between epiglottis & esophagus Esophagus Trachea The posterior and lateral walls are 3 skeletal muscles (constrictors) that propel food/liquid inferiorly to the esophagus. Constrictors innervated by CNX. Additional muscles elevate the pharynx (stylopharyngeus is external). Stylopharyngeus innervated by CNIX. Stylopharyngeus Superior constrictor Middle constrictor Inferior constrictor Two additional internal muscles we’ll get to later… Key relationship: Glossopharyngeal nerve wraps around stylopharyngeus muscle. CN IX wraps around stylopharyngeus muscle and Stylopharyngeus innervates it. Pharyngeal constrictors Pharynx Interior 1 Nasopharynx: 1. Pharyngeal tonsils 2. Auditory tube ostia 2 3 3. Salpingopharyngeal fold 4 4 Oropharynx: 4. Palatine tonsils 5 5 Laryngopharynx: Slit open 5. Piriform recess constrictors to examine interior Lateral Wall of Pharynx 5. Salpingopharyngeus muscle 6. Levator veli palatini muscle 1. Pharyngeal tonsils 7. Tensor veli palatini muscle 2. Torus tubarius 8. Palatine tonsil 3. Auditory tube opening 9. Palatoglossal fold/muscle 4. Salpingopharyngeal fold 10. Palatopharyngeus fold/muscle 1 Nasal 2 3 cavity 1 7 2 6 3 5 4 Oral 9 10 cavity 9 8 10 Summary Rule for Innervation of Muscles of Pharynx and Palate All muscles of the pharynx and palate are innervated by the vagus nerve, except: • Stylopharyngeus which is IX • Tensor veli palatini which is V3 Sensory Innervation to Pharynx Glossopharyngeal “Gag Reflex” Vagus Larynx Vocalization Laryngeal Cartilages and Ligaments Larynx functions in phonation & respiration Epiglottis Hyoid Internal br. superior laryngeal n. Thyrohyoid membrane Arytenoids Thyroid cartilage Arytenoid cartilages (ghosted in) Cricoid cartilage Trachea Cricothyroid membrane Laryngeal Cartilages and Ligaments Epiglottis Vestibular ligament Thyroid When covered with Arytenoid mucosa they become folds. Vocal ligament Cricoid Emergency cricothyrotomy The interior of the larynx is covered by mucosa and divided into upper (supraglottic) and lower (infraglottic) regions by the glottis. What is the glottis? Vestibular Supraglottic region Right & left vocal fold, left Innervated by internal br. superior laryngeal n. cords plus space in between them. Vocal ligament, right Glottis changes dimensions Infraglottic region during respiration/phonation. Innervated by recurrent laryngeal n. Vocal Cords While Singing Right Vocal Cord Paralysis The 11 laryngeal skeletal muscles function to ADDUCT, ABDUCT and adjust TENSION on the vocal cords during phonation and respiration. You are only responsible for two: cricothyroid and posterior cricoarytenoid. Synovial Tenses Abducts joint Cricothyroid Posterior cricoarytenoid External branch of Recurrent laryngeal superior laryngeal nerve nerve The right & left ventricles are small pockets between vestibular & vocal folds. They are rich in mucous glands that moisten the vocal cords. Epiglottis Arytenoid Cricoid Coronal section Opening into ventricle Nasal Cavity Olfaction and Respiration Nasal Cavity Roof: cribriform plate Lateral walls: Concha Nasal septum (turbinates) Three conchae project Floor: hard palate medially from lateral wall to create more surface area for humidifying & adjusting air temperature. There are 4 pairs of paranasal sinuses, each named according to the bone they lie in: Frontal Sphenoid Ethmoid Maxillary Mucosa lining sinuses produces nitric oxide which is antiviral and bacteriostatic. Thereby they assist immune system. Nasal Cavity Osteology Lateral Wall Frontal Bone Ethmoid Bone: 1. cribriform plate 2. superior concha 3. middle concha Nasal Bone 1 Sphenopalatine foramen 2 Lacrimal Bone 6 3 10 4 Inferior Nasal Concha 9 Sphenoid Bone: 5 9. med. pterygoid plate 7 10. sphenoid sinus Maxilla: 8 6. nasal surface 7. palatine process Palatine Bone: 8. alveolar process 4. perpendicular plate 5. horizontal plate Nasal Cavity Meatuses Superior concha Middle concha Auditory? tube opening Inferior concha A meatus is the space immediately lateral to a concha. Drainage Ostia Within Nasal Cavity Sphenoethmoidal: Sphenoid sinus Semilunar Superior meatus: hiatus Ethmoids (post.) Middle meatus: Frontal sinus Maxillary sinus Ethmoids (ant & mid) Inferior meatus: Nasolacrimal duct Nasal Cavity Mucosal Innervation: Sensory V1 & V2 1. nasal branches of 2. anterior ethmoidal br. of nasociliary nerve 3. lateral nasal branches 2 4. nasopalatine nerve 1 3 1 3 V1 V1 3 4 V V2 2 3 3 4 4. Passes thru incisive canal to innervate maxillary anterior teeth. Lateral Wall Septum Nasal Cavity: Blood Supply Blood supply is via the maxillary artery which passes thru pterygopalatine fissure to give rise to 3 terminal branches: 1. sphenopalatine, 2. descending palatine and 3. infraorbital. 1 3 2 Nasal Cavity: Blood Supply These arteries anastomose within nasal cavity, representing an anastomosis between external and internal carotid arteries. Epistaxis = nosebleed Anterior & posterior ethmoids Branches of ophthalmic (ICA) Sphenopalatine (ECA) Branches of facial (ECA) Pterygopalatine Fossa PT Fossa, V2 & Maxillary Artery Pterygopalatine Fossa Small, cone-shaped fossa with 6 openings: 1 laterally, 1 medially, 1 anteriorly, 1 inferiorly and 2 posteriorly. Houses pterygopalatine ganglion, V2 & terminal branches of maxillary artery. 1 2 Lateral View Medial View 1. Pterygomaxillary fissure 2. Sphenopalatine foramen Once you break plane of fissure you Opening from pterygopalatine are in pterygopalatine fossa. fossa into nasal cavity. Transmits maxillary artery Transmits sphenopalatine artery Two Posterior Openings V2 4. Pterygoid canal 3. foramen rotundum Transmits maxillary nerve Transmits nerve of pterygoid canal (Vidian’s nerve) How to cannulate the pterygoid canal Medial pterygoid plate Pterygoid canal Foramen magnum Inferior Opening in PT Fossa 5. palatine canal Transmits greater & lesser palatine nerves & descending palatine artery; exits are greater & lesser palatine foramina. One Anterior Opening Leading Out of in PT Fossa 6. Inferior orbital fissure Transmits infraorbital nerve Summary of 4 openings in PT Fossa Sphenopalatine foramen Foramen rotundum Pterygoid canal Palatine canal Inferior orbital fissure Pterygopalatine Ganglion: Para/pre Para/post Greater petrosal nerve from facial Greater petrosal nerve Geniculate ganglion VII Pterygopalatine Ganglion: Para/pre Para/post 1. Lateral nasal branches 4. Branch to maxillary n. V 2 Greater petrosal nerve from facial 1 4 Mucosal 1 glands Sympathetics Mucosal 1 2 Nerve of pterygoid glands 3 canal (Vidian’s nerve) 3. Lesser palatines 3 2 Paltine glands 2. Great palatine nerves Thus, lacrimal gland is innervated by VII via PT ganglion. 1. Anterior 2. Middle Superior alveolar nerves 3. Posterior Hitchhiking on lacrimal nerve Lacrimal gland 1 Mucosa maxillary 2 3 sinus Any Questions?.