Pharynx Anatomy PDF

Pharynx DPM Program Learning Objectives: 1. Explain the structure and function of the pharynx, including the auditory tube. 3.0 2. Describe the piriform recess. 3.0 3. List the components and functions of the pharyngeal plexus. 3.0 4. Describe the blood supply and venous drainage of the pharynx. 2.0...

Pharynx DPM Program Learning Objectives: 1. Explain the structure and function of the pharynx, including the auditory tube. 3.0 2. Describe the piriform recess. 3.0 3. List the components and functions of the pharyngeal plexus. 3.0 4. Describe the blood supply and venous drainage of the pharynx. 2.0 5. Describe the roles the soft palate, pharyngeal constrictors, and tongue in swallowing. 3.0 6. Describe the anatomic arrangement and functional significance of the lymphoid tissue in the tonsils, pharyngeal, and posterior nasal walls. 3.0 7. Give the nerve and blood supply to the palatine tonsil. 3.0 8. Identify common sites that foreign bodies can become lodged. 3.0 1 Overview of the Respiratory System Upper Respiratory System Paranasal sinuses Nasal conchae Nose Nasal cavity Posterior nasal apertures Nasopharynx Tongue Hyoid bone Lower Respiratory System Larynx Esophagus Trachea Bronchi Lungs Clavicle Bronchioles RIGHT LUNG Ribs LEFT LUNG Diaphragm 2 The Pharynx The pharynx is a passageway that connects the nose to the mouth to the throat. Begins at base of the skull to the inferior border of cricoid cartilage (C6) where it continues with the esophagus. Composed of skeletal muscle and mucous membranes. Contraction of the skeletal muscle assists in deglution (swallowing) Shared by respiratory and digestive systems divided into three parts: Nasopharynx (C1) Posterior to the nose and superior to the soft palate Contains pharyngeal opening of auditory (Eustachian) tube Oropharynx (C2, C3) Posterior to the mouth ends at upper border of the epiglottis Consists of pharyngeal arch and uvula Laryngopharynx (C4, C5, C6) The area that has the entrance to the trachea and esophagus extending from the superior border of the epiglottis to the inferior border of the cricoid cartilage where it is continuous with the esophagus Posterior to the larynx 3 The Nasopharynx Lies posterior to the nasal cavity and extends to the soft palate. Pharyngeal tonsil (adenoids when enlarged) Concentrations of lymphoid tissue in the mucous membrane of the roof and posterior nasopharynx Opening of the pharyngotympanic tube Leads to the inner ear Hard palate Salpingopharyngeal fold Covers the salpingopharyngeus muscle, which opens the pharyngeal orifice of the pharyngotympanic tube during swallowing Soft palate Forms the posterior portion of the roof of the mouth 4 The Oropharynx Has a digestive function and extends from the soft palate to the superior border of the epiglottis. Salpingopharyngeal fold Covers the salpingopharyngeus muscle. Hard palate Soft palate Forms the posterior portion of the roof of the mouth Palatoglossal arch Palatine tonsil Soft palate Genioglossus m. Palatopharyngeal arch Covers the palatopharyngeus muscle. Palatoglossal arch Palatopharyngeal arch Palatine tonsil **Palatine tonsil is innervated by the glossopharyngeal nerve. 5 Tonsils (aggregations of lymphoid tissue) WALDEYER’S TONSILLAR RING -A ring of lymphoid tissue around the oropharynx and nasopharynx formed by the lingual tonsils, the palatine tonsils, the tubal tonsils, and the pharyngeal tonsil -Efferent lymphatics drain as follows: a) From roof and posterior wall – to retropharyngeal nodes. b) From region of palatine tonsil – to deep cervical nodes. c) From the laryngopharynx – to deep cervical nodes. 6 Laryngopharynx Deep depressions found on either side of the larynx; assist in channeling food into the laryngopharynx when the epiglottis is closed. CLINICAL NOTES -A foreign object lodged within the piriform recess will initiate the gag reflex Piriform Recess -The INTERNAL and RECURRENT LARYNGEAL NERVES (both branches of the Vagus) to the muscles of the larynx lie deep to the mucosa of the piriform recess. If the foreign object alluded to above is sharp, it may pierce the mucous membrane and damage the internal and/or recurrent laryngeal nerves 7 8 External Muscle Layer of the Pharynx The wall of the pharynx has a muscular layer composed entirely of voluntary muscle arranged mainly into an external circular and internal longitudinal layer. The external circular layer shown here will constrict the walls of the pharynx during swallowing. Used to propel food into esophagus during swallowing (peristalsis). Includes: Superior, Middle & Inferior Constrictors Innervation: Vagus nerve Lateral View Posterior View 9 Internal Muscle Layer: Longitudinal Muscles Internal (mainly longitudinal) layer of muscle consists of: -Salpingopharyngeus m. -Palatopharyngeus m. -Stylopharyngeus m. These muscles elevate the larynx and the pharynx during swallowing.. -Innervated by vagus nerve -Innervated by vagus nerve -Innervated glossopharyngeal nerve (only muscle not innervated by the vagus nerve) Posterior View 10 Pharyngeal Muscles (Posterior View) 11 Vessels of the Pharynx ARTERIES supplying the pharynx: -Ascending pharyngeal (from external carotid) -Superior thyroid (from external carotid) -Ascending & descending palatine -from facial/maxillary -Pharyngeal branches of maxillary artery ARTERIES to the palatine tonsil: Lower Pole: -Tonsillar branch of facial a. -Tonsillar branch of Ascending Palatine -Tonsillar branch of dorsal lingual a. Upper pole: -Tonsillar branch of the ascending pharyngeal -Tonsillar branch of the Lesser palatine (descending palatine) VEINS: PHARYNGEAL VENOUS PLEXUS -drains into internal jugular vein 12 The Pharyngeal Plexus Pharyngeal Plexus Constrictors are innervated by the pharyngeal plexus formed by: -glossopharyngeal nerve (CN IX) -vagus nerve (CN X) - Postganglionic sympathetic fibers from superior cervical ganglion (supply blood vessels) 13 Pharyngeal Nerves The nerve supply to the pharynx (motor and most of sensory) derives from the pharyngeal plexus of nerves. MOTOR FIBERS: derived from vagus nerve (CN X) -supplies all muscles of the pharynx and soft palate, except the stylopharyngeus m (supplied by CN IX, glossopharyngeal n.) SENSORY FIBERS: derived from CN IX (glossopharyngeal n.) Internal jugular vein Spinal Accessory Nerve Hypoglossal nerve Glossopharyngeal nerve Superior cervical ganglion Sympathetic trunk Common carotid artery Vagus nerve Pharyngeal plexus 14 Summary of Neurovasculature 15