The Pharynx Lecture 2024 PDF

THE PHARYNX Wide muscular tube behind nose, mouth & larynx Upper part transmits air only Middle part transmits food & air (only one at a time) Lower part LINE OF ATTACHMENT OF PHARYNX TO BASE OF SKULL  STRUCTURE OF PHARYNX Wall is composed of 5 layers from within o...

THE PHARYNX Wide muscular tube behind nose, mouth & larynx Upper part transmits air only Middle part transmits food & air (only one at a time) Lower part LINE OF ATTACHMENT OF PHARYNX TO BASE OF SKULL  STRUCTURE OF PHARYNX Wall is composed of 5 layers from within outwards Mucosa Submucosa Pharyngobasilar fascia Muscular coat Buccopharyngeal fascia  3 PARTS Nasopharynx Oropharynx Laryngopharynx  NASOPHARYNX LOCATION : Situated behind nose & above lower border of soft palate FUNCTIONS Respiratory- no food ever enters it Walls are rigid & non- collapsible so air passage is kept patent Lined by ciliated columnar epithelium Mucus membrane supplied by  NASOPHARYNX cont. Wallsformed by pharyngo- basilar fascia & posterior median ligament Communicates with nasal cavities through posterior nasal apertures Communicates with oropharynx at pharyngeal isthmus Lateral wall has : Opening of auditory tube Tubal elevation Salpingopharyngeal fold Levator palati Pharyngeal recess Roof& posterior wall form continuous slope opposite posterior part of body of sphenoid  OROPHARYNX Middle part situated behind oral cavity Walls made of superior, middle, inferior constrictors Communications Above : nasopharynx via pharyngeal isthmus Infront : oropharynx via oropharyngeal isthmus Behind : Supported by C2 + C3 vertebrae Lateral wall : Palatine tonsil lying in tonsillar fossa (bounded by palatoglossal & palatopharyngeal arches) LARYNGOPHARYNX Lowest part situated behind larynx Extends from upper border of epiglottis to lower border of cricoid cartilage ANTERIOR WALL Inlet of larynx Cricoid & arytenoid cartilages POSTERIOR WALL C3-6 vertebrae MUSCLES OF PHARYNX 3 CONSTRICTORS Superior Middle Inferior LONGITUDINAL MUSCLES Stylopharyn geus Salpingopharyngeus MUSCLES OF PHARYNX CONT 3 CONSTRICTOR S SUPERIOR MIDDLE & INFERIOR  STYLOPHARYNGEUS SALPINGOPHARYNGEUS PALATOPHARYNGEUS MUSCLES OF PHARYNX SUPERIOR CONSTRICTOR Origin Pterygoid hamulus Pterygomandibular raphe Medial surface of mandible at end of mylohyoid line Side of tongue  MUSCLES OF PHARYNX MIDDLE CONSTRICTOR Origin Stylohyoid ligament Lesser cornu of hyoid bone Greater cornu of hyoid bone  MUSCLES OF PHARYNX INFERIOR CONSTRICTOR Has 2 parts THYROPHARYNGEUS Origin Oblique line of thyroid lamina Cricothyroid muscle CRICOPHARYNGEUS Origin Cricoid cartilage  MUSCLES OF PHARYNX Insertion of constrictors Onto a median raphe on posterior wall of pharynx Upper end of raphe reaches base of skull where it is attached to pharyngeal tubercle on occipital bone LINE OF ATTACHMENT OF PHARYNX TO BASE OF SKULL  LONGITUDINAL MUSCLES OF PHARYNX STYLOPHARYNGEUS Origin Styloid process Insertion Inner surface of middle & inferior constrictors  LONGITUDINAL MUSCLES OF PHARYNX PALATOPHARYNGEUS Origin Side of hard palate Insertion Thyroid cartilage & blends with constrictor fibers  LONGITUDINAL MUSCLES OF PHARYNX SALPINGOPHARYNGEUS Origin Auditory tube Insertion Thyroid cartilage & inferior constrictor SUMMARY OF LONGITUDINAL MUSCLES OF PHARYNX Muscle Origin Insertion Innervation Main Actions Superior Hamulus, Median Vagus via Constricts wall of pharyngeal raphe of pharynge al pharynx during constrictor pterygomandibular pharynx plexus swallowing raphe, mylohyoidline of mandible Middle Stylohyoid Median Vagus via Constricts wall pharyngeal ligament and raphe of pharynge al of pharynx constrictor horns of hyoid pharynx plexus during bone swallowing Inferior Oblique line of Median Vagus via Constricts wall pharyngeal thyroid cartilage, and raphe of pharynge al of pharynx constrictor cricoid cartilage pharynx plexus during swallowing Salpingoph Auditory Side of Vagus via Elevates pharynx aryngeus (pharyngotympani c) pharynx pharynge al and larynx during tube wall plexus swallowing and speaking Stylophary Medial aspect of Pharyngeal Glossophary Elevates pharynx ngeus styloid process wall ngeal nerve and larynx during swallowing and speaking palatophar Posterior border of Posterior Vagus via Elevates pharynx yngeus hard palate, palatine border of pharynge al superiorly, anteriorly aponeurosis thyroid plexus and medially cartilage (shortening it to swallow)  GAPS BETWEEN PHARYNGEAL MUSCLES Above superior pharyngeal constrictor: auditory tube levator palati ascending palatine artery Between superior & middle constrictors: stylopharyngeus muscle glossopharyngeal nerve Between middle & inferior constrictors: internal laryngeal nerve superior laryngeal artery Below inferior constrictor: inferior laryngeal nerve  NERVE SUPPLY MOTOR INNERVATION All muscles 1. Vagus & Spinal accessory 2. Recurrent laryngeal (inferior constrictor) Except Stylopharyngeus (CN IX- Glosso..) 1. Glossopharyngeal SENSORY INNERVATION Glossopharyngeal (to oropharynx region) Vagus to remainder of pharynx  ACTIONS OF MUSCLES Deglutition Pharynx drawn upward & dilated in different directions to receive the food propelled into it from the mouth Stylopharyngei Draw sides of pharynx upward & lateralward, & increases its transverse diameter; its breadth in the antero-posterior direction is increased by the larynx & tongue being carried forward in their ascent As soon as bolus of food is received in pharynx, elevator muscles relax, pharynx descends Constrictors Contract upon bolus & convey it downward into esophagus  BLOOD SUPPLY Branches from: 1. External carotid artery 2. Facial artery 3. Lingual artery 4. Branches of maxillary artery  VENOUS DRAINAGE Plexus on posterolateral aspect of pharynx Drain into IJV & facial vein LYMPHATIC DRAINAGE Retropharyngeal & deep cervical lymph nodes  Dr OS Aladeyelu Email: [email protected] WhatsApp: 065 697 5373