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The pharynx الدكتور سعد يونس سليمان كلية طب نينوى Lecture Objectives Anatomy Divisions of the pharynx The pharyngeal wall .. Killian’s Dehiscence Nerve supply of the pharynx Waldeyer’s ring… Palatine tonsils Retropharyngeal space ( Space of Gillette) Parapharyngeal Space Functions of the pharynx Anatomy of The pharynx Shape Irregular conical Fibromuscular tube Length: 12-14 cm Anatomy of The pharynx Divisions • Nasopharynx • Oropharynx • Laryngopharynx (Hypopharynx) • • • • Form the upper part of air & food passages Extends from base of skull to inferior border of cricoid cartilage anteriorly and inferior border of C6 posteriorly Widest portion (5cm) at hyoid Narrowest portion (1.5cm) at its caudal end(Pharyngooesophageal junction) 1 2 3 4 5 6 Nasopharynx Extends from base communicates anteriorly with the of the skull to the nasal through levelcavity of hard the posterior nares palate (choanae) so it has a respiratory function Three important structures in the nasopharynx Nasopharyngeal tonsil (adenoid) Openings of the Eustachian tubes Fossa of Rosenmuller Nasopharynx ( Summary) •Anteriorly; nasal cavity •Posterosuperiorly; basisphenoid …adenoid •Posteriorly; extend down to the junction of the hard and soft palate in front of C1 (atlas) •Inferiorly; the superior surface of the soft palate and opens into the oropharynx. •Laterally; openings of the Eustachian tubes Eustachian cushions, fossae of Rosenmuller. Oropharynx Behind the oral cavity (in front of 2nd&3rd Cervical vertebrae) from the level of hard palate to the level of hyoid bone( ant. to C2& C3 ). Communicates: Anteriorly with the oral cavity Superiorly with the nasopharynx Inferiorly with the hypopharynx The palatine tonsils lie laterally between the anterior and posterior pillars Oropharynx (cont.) The dividing line between the oropharynx and mouth is: junction of hard palate and soft palate above anterior pillar laterally junction of anterior 2/3 and posterior 1/3 of the tongue (circumvallate papillae). Digestive function Anterior: anterior tonsillar pillar Posterior: superior constrictor Superior: soft palate Inferior: base of tongue, superior epiglottis Laterally: palatoglossal and palatopharyngeal arches The tonsils lie between the Two pillars Hypopharynx Behind the Larynx (in front of 3rd to 6th Cervical vertebra) from the level of hyoid to the upper end of esophagus at the level of the inferior border of the cricoid cartilage inferiorly Communicates: Anteriorly with the Larynx Superiorly with the oropharynx Inferiorly with the oesophagus Cricoid cartilage Seen from behind The hypopharynx does not only lie behind the larynx BUT also Projects laterally on each side of the larynx So it is formed of : - Postcricoid region ( behind the larynx) - Two pyriform fossa (on each side of the larynx) - Posterior pharyngeal wall Cross section The structure of pharyngeal wall The wall is formed of 4 layers 1-Mucous membrane 2- Pharyngeal aponeurosis 3-Muscle coat 4-Bucco-pharyngeal fascia a (outer strong fibrous layer attached superiorly the baseconstrictor of the it skull. A This Circular thin iscoat of connective layer), superior, tissue, this middle fascia and isnasopharynx, inferior loosely attached Stratified squamous epithelium except theto is It is strengthened posteriorly by strong fibrous band called “median muscles posteriorly to the prevertebral fascia and laterally it is pseudostratified ciliated columnar epithelium withofgoblet pharyngeal raphe”. This raphe attaches above to the base the skull, connected to the styloid process and the carotid sheath. cells Longitudinal ( internal Stylopharyngeus and gives insertion to the),constrictor muscles. Salpingopharyngeus Palatopharyngeus Inferior constrictor muscle has two parts: 1. Thyropharyngeus with oblique fibers. 2. Cricopharyngeus with transverse fibers. Killian’s Dehiscence This is a potential gap between fibers of thyropharyngeus and cricopharyngeus muscles. Normally cricopharyngeus muscle relaxes when food bolus is pushed by the pharynx towards the esophagus. If this does not happen, mucosa will bulge outward forming a pharyngeal pouch. Nerve Supply Motor ---► X Except : Stylopharyngeus --►IX Tensor palati --► V Sensory --► Nasopharynx: V - Oropharynx: IX - Laryngopharynx: X Autonomic: - sympathetic: SCG - Parasympathetic: through VII - Waldeyer’s ring: Definetion: It is a collection of lymphoid tissue in the nasopharynx and oropharynx at the entrance to the airodigestive tract. It is composed of: 1. 2. 3. 4. 5. 6. Nasopharyngeal tonsil (adenoid) Tubal tonsils: lie behind the opening of the Eustachian tubes. Palatine tonsils. Lingual tonsils: embedded in the posterior 1/3 of the tongue. Lateral pharyngeal bands: behind the posterior tonsillar pillars, Lymphoid nodules: scattered on the posterior pharyngeal wall. Hypertrophy of the lymphoid tissue of Waldeyer’s ring occurs in the earlier years of childhood, probably in response to URTI. Maximum hypertrophy occurs between 4-10 years, thereafter some regression in size is to be expected, and in old age it atrophies. Waldeyer’s ring is characterized by: 1. 2. 3. 4. 5. Sub-epithelial lymphoid tissue. Lack of definite capsule. They have efferent lymph vessels, but NO afferent vessels. They function as one unit; when a member of it is removed the other parts undergo compensatory hypertrophy. The exact function is unknown but it is thought that it has a protective function by: Formation of lymphocytes. Secretion of antibodies mainly IgA. Localization of infection entering the body by initial contact with the incoming organism. Palatine tonsils Two masses of lymphoid tissue situated on each side of oropharynx Its medial surface is pitted by a number of crypts. Laterally the tonsil is enclosed by a dense fibrous capsule separating the tonsil from the superior constrictor (tonsillar bed) plane for dissection of the tonsil during tonsillectomy. Blood supply of the tonsil From the External Carotid Artery & its branches 1- Tonsillar artery (from Facial Artery) 2-Ascending palatine artery (from Facial Artery) 3-Ascending pharyngeal Artery (from external carotid) 4-Descending palatine artery ( from Maxillary artery. 5-Dorsalis lingulae artery (from Lingual artery) Venous drainage To the paratonsillar veins which drains to the pharyngeal plexus. The plexus drain to the internal jugular veins. Retropharyngeal space ( Space of Gillette) It is a potential space that lies between the pre vertebral fascia posteriorly and the buccopharyngeal fascia anteriorly. It extend from the base of the skull to the superior mediastenum. It contains retropharyngeal lymph nodes of Rouviere: few lymph nodes that disappear spontaneously during the 3rd or 4th year of life. Prevertebral space Prevertebral fascia Bucco-pharyngeal fascia Parapharyngeal space Retropharyngeal space Parapharyngeal Space lateral to the pharynx and connects posteriorly with the retropharyngeal space. It extends from the base of the skull to the hyoid bone (i.e. it is lateral to the nasopharynx and oropharynx ). Boundaries of parapharyngeal space Medially: superior constrictor muscle laterally: medial ptrygoid muscle, mandible and deep lobe of parotid gland. Posteriorly: the prevertebral muscle and fascia. Contents of parapharyngeal space 1. 2. 3. Deep cervical lymph nodes. Last 4 cranial nerve and cervical sympathetic trunk. Great vessels of the neck; common carotid artery and internal jugular vein. Functions of the pharynx 1. 2. 3. 4. Food and air inlet. Play an important role in speech through vocal resonance and articulation. The immunologic function of Waldeyer's ring. Deglutition; which is divided into three stage; Oral stage ( voluntary ) Pharyngeal stage ( involuntary ) Eosophageal stage ( involuntary ) وآخر دعوانا أن الحمد هلل رب العالمين والسالم عليكم ورحمة هللا وبركاته