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Anatomy and Physiology of Pharynx.ppt
The pharynx is a conical tube that extends from the base of the skull to the lower border of the cricoid cartilage. It is divided into three parts: the nasopharynx, oropharynx, and hypopharynx. The pharynx acts as a passageway for air and food and plays an important role in swallowing, speech, and drainage of the middle ear. It contains important structures like the tonsils and adenoids that help protect the respiratory and digestive tracts from infection. Blood supply comes from branches of the external carotid artery and it is innervated by nerves from the pharyngeal plexus including the vagus and glossopharyngeal nerves.
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Anatomy and Physiology of Pharynx.ppt
- 1. Anatomy and Physiology ofPharynx Dr. Vijay Kumar Dr. Vijay Kumar
- 2. Pharynx Pharynx is aconical fibromuscular tube forming upper part of aero-digestive tract 12-14 cms, extends from base of skull to lower border of cricoid cartilage (C6). Width is 3.5 cms at base & 1.5 cms at pharyyngo-oesophageal junction, which is the narrowest part in GIT.
- 3. Mucous membrane Pharyngeal aponeurosis / Pharyngobasilar fascia Muscular coat Buccopharyngeal fascia Ciliated columnar in nasopharynx & stratified squamous in rest of pharynx
- 4. Killian’s dehiscence Inferiorconstrictor muscle- thyropharyngeus –oblique fibres cricopharyngeus – transverse fibres Potential gap- Killian’s Dehiscence “Gateway of tears” – perforation can occur at this site during oesophagoscopy. Pharyngeal pouch- herniation of pharyngeal mucosa
- 5. Waldeyer’s Ring Subepithelial layerof lymphoid tissue Nasopharyngeal tonsil/adenoids Palatine tonsil Tubal tonsil Lateral pharyngeal bands Nodules-posterior pharyngeal wall
- 6. Pharyngeal Spaces Retropharyngealspace- from base of skull to bifurcation of trachea between buccopharyngeal fascia & prevertebral fascia. Divided by median raphe into two (space of Gillette) Prevertebral space - between vertebral bodies & prevertebral fascia, extends from base of skull to coccyx
- 7. Parapharyngeal space Medial:buccopharyngeal fascia covering constrictors Posterior: prevertebral fascia Lateral: medial pterygoid muscle, mandible. Styloid complex- divides into anterior & posterior compartment. Antr- tonsillar fossa medially & pterygoid muscle laterally Postr- pharyngeal wall med & parotid laterally. Carotid art, jugular vein, IX, X, XI, XII CN, & nodes
- 8. Pharynx Nasopharynx, Oropharynx& Hypopharynx Nasopharynx Epipharynx: from base of skull to plane passing through hard palate Roof: basisphenoid & basiocciput Posterior wall: atlas vertebra with muscles Floor: anteriorly soft palate & posteriorly communicates with the oropharynx through nasopharyngeal isthmus
- 10. Lateral wall: E.tube1.25cms behind IT Torus tubaris- elevation behind tubal opening Fossa of Rosenmuller- site for origin of Nasopharyngeal Carcinoma Salpingopharyngeal fold Tubal tonsil: part of Waldeyer’s ring Adenoids-Nasopharyngeal tonsil upto12 years, later atrophies
- 11. Nasopharyngeal bursa Epithelial linedmedian recess within adenoids Extends from pharyngeal mucosa to basiocciput Represents attachment of notochord to pharyngeal entoderm during embryonic life Infection – persistent postnasal discharge Thornwaldt’s disease- abscess
- 12. Rathke’s pouch:remniscent of buccal mucosal invagination,forming antr lobe of pituitary. Craniopharyngioma may arise from this site Sinus of Morgagni: space between base of skull & upper free border of superior constrictor . E.tube, tensor veli palatine, levator veli paltine enters along with ascending palatine artery br of facial artery Passavant’s ridge: mucosa ridge raised by palatopharyngeus. Deglutition, cuts off NP from OP
- 13. Lined bypseudostratified ciliated columnar epithelium Lymphatics drain into upper deep cervical nodes either directly or thro’ retro/parapharyngeal nodes Functions Conduit of humidified air into larynx/trachea Ventilates ME thro’ E.tube, equalizes air pressure. Cuts off oropahrynx during deglutition, vomiting, speech Resonating chamber Drainage channel for mucous secreted by nasal glands
- 14. Oropharynx Extends fromplane of hard palate above to plane of hyoid bone below Communicates with oral cavity thro’ oropharyngeal isthmus. Posterior wall: related to retropharyngeal space, C2-C3 Anterior wall: above opens into oral cavity, & below related to base of tongue, lingual tonsil, valleculae Lateral wall: anterior & posterior pillars, faucial tonsil Lower limit is by upper border of epiglottis & pharyngoepiglottic folds
- 15. Lymphatics draininto upper jugular chain-JD nodes, also to retro & para pharyngeal nodes. Functions Conduit for passage of air & food Pharyngeal phase of deglutition Vocal tract for certain speech sounds Taste sensation-BOT, soft palate, pillars, PP wall Local defence & immunity at entrance of aerodigestive tract- Waldeyer’s ring
- 16. Hypopharynx (Laryngopharynx) It liesbehind & sides of larynx Extends from plane passing from hyoid bone to lower border of cricoid cartilage, (C3-C6). Three regions: Pyriform sinus, post cricoid region & posterior pharyngeal wall. Pyriform fossa: either side of larynx. Internal laryngeal nerve runs submucosally in lat wall, cause referred pain in carcinoma
- 18. Post-cricoid region:cricoid lamina, site for carcinoma in pt’s with Plummer-Vinson syndrome Posterior pharyngeal wall: from level of hyoid bone to crcoarytenoid joint. Lymphatic drainage: upper jugular chain, parapharyngeal nodes, supraclavicular. Functions: Conduit for air & food, Vocal tract resonance Takes part in deglutition Failure of cricopharyngeal sphincter to relax when pharyngeal muscles contract- hypopharyngeal diverticulum
- 19. Structures passing through Abovesuperior constrictor E.tube, tensor palati, levator palati muscles Palatine br ascending pharyngeal artery Between superior & middle constrictor Stylopharyngeus muscle, glossopharyngeal n Between middle & inferior constrictor Internal laryngeal n, superior laryngeal vessels. Below inferior constrictor Recurrent laryngeal nerve, inferior laryngeal art
- 20. Blood supply: branchesof external carotid art Ascending pharyngeal, Dorsal lingual artery Ascending palatine & tonsillar artery Branches of internal maxillary artery Nerve supply: pharyngeal plexus formed by Pharyngeal br of vagus & glossopharyngeal Pharyngeal br of superior cervical sympathetic ganglion Vagal fibres are motor, glossopharyngeal is sensory & sympathetic is vasomotor
- 21. Functions of Pharynx Deglutition Protection from aspiration Part of respiratory & food passage Speech adds resonance to the voice Waldeyer’s ring is involved Taste sensation Mucous from respiratory tract is swallowed E.tube ventilates & drains the middle ear cleft
- 22.