Unit 2 - Pharynx, Larynx, Trachea PDF

Diploma in Physiotherapy Please do not reproduce, redistribute or share without the prior express permission of the author.  Lecture notes ANATOMY II PHARYNX, LARYNX, TRACHEA Please do not reproduce, redistribute or share without the prior express permission of...

Diploma in Physiotherapy Please do not reproduce, redistribute or share without the prior express permission of the author.  Lecture notes ANATOMY II PHARYNX, LARYNX, TRACHEA Please do not reproduce, redistribute or share without the prior express permission of the author.  Learning Outcome At the end of the lesson, students will be able to: Describe the structure, divisions, muscles, action and innervation of Pharynx. Identify and explain about Hyoid bone. Describe about larynx and laryngeal cartilages, muscles and its movements. Explain about Trachea Describe the mechanics of phonation and speech Please do not reproduce, redistribute or share without the prior express permission of the author.  Pharynx It is a funnel – shaped passageway commonly called as THROAT that connects the nasal cavity and mouth superiorly to the larynx and esophagus inferiorly. It descends from the base of the skull to the level of the sixth cervical vertebra and serves as a common passage way for both food and air. Please do not reproduce, redistribute or share without the prior express permission of the author.  On the basis of location and function, the pharynx is divided into: Nasopharynx Oropharynx Laryngopharynx Please do not reproduce, redistribute or share without the prior express permission of the author.  The Nasopharynx  The nasal part of the pharynx has a respiratory function.  It lies superior to the soft palate and is a posterior extension of the nasal cavity.  The nose opens into the nasopharynx via to large posterior apertures called choanae. Please do not reproduce, redistribute or share without the prior express permission of the author.  The Oropharynx The oral part of the pharynx has a digestive function. It is continuous with the oral cavity through the oropharyngeal isthmus. Please do not reproduce, redistribute or share without the prior express permission of the author.  The Laryngopharynx  The laryngeal part of the pharynx lies posterior to the larynx.  It extends from the superior border of the epiglottis to the inferior border of the cricoid cartilage, where it narrows to become continuous with the oesophagus.  Posteriorly, the laryngopharynx is related to the bodies of C4 to C6 vertebrae. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author.  The Layers of the Pharyngeal Wall The pharyngeal wall is composed of 5 layers. From internal to external, they are as follows.  Mucous membrane: this lines the pharynx  Submucosa  Pharyngobasilar fascia: this is a fibrous layer that is attached to the skull.  Muscular layer: this is composed of inner longitudinal and outer circular parts.  Buccopharyngeal fascia: this is a loose connective tissue layer. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author.  Muscles of the Pharynx The pharyngeal muscles are a group of muscles that act upon the pharynx. This consists of three constrictor muscles and three muscles that descend from the styloid process, the cartilaginous part of the auditory tube and the soft palate. Please do not reproduce, redistribute or share without the prior express permission of the author.  They include:  Inferior constrictor muscle External  Middle constrictor muscle circular part  Superior constrictor muscle  Stylopharyngeus muscle  Salpingopharyngeus muscle  Palatopharyngeus muscle Please do not reproduce, redistribute or share without the prior express permission of the author. Muscle Of Pharynx Please do not reproduce, redistribute or share without the prior express permission of the author.  External Muscles of the Pharynx  The paired superior, middle, and inferior constrictor muscles form the external circular part of the muscular layer of the wall.  These muscles overlap each other and are arranged so that the superior one is innermost and the inferior one is outermost. Please do not reproduce, redistribute or share without the prior express permission of the author.  Muscle action These muscles contract involuntarily in a way that results in contraction taking place sequentially from the superior to inferior end of the pharynx. This action propels food into the oesophagus. Please do not reproduce, redistribute or share without the prior express permission of the author.  Internal Muscles of the Pharynx  The internal, chiefly longitudinal muscular layer, consists of 3 muscles: stylopharyngeus, palatopharyngeus, and salpingopharynges. Action:  They all elevate the larynx and pharynx during swallowing and speaking. Please do not reproduce, redistribute or share without the prior express permission of the author.  Innervation of the Pharynx  The motor and most of the sensory supply of the pharynx is derived from the pharyngeal plexus of nerves on the surface of the pharynx.  The plexus is formed by pharyngeal branches of the vagus (CN X) and glossopharyngeal (CN IX) nerves, and by sympathetic branches for the superior cervical ganglion. Please do not reproduce, redistribute or share without the prior express permission of the author.  The motor fibres in the pharyngeal plexus are derived from the cranial root of accessory nerve (CN XI), and are carried by the vagus nerve to all muscles of the pharynx and soft palate.  The exceptions are stylopharyngeus (supplied by CN IX) and the tensor veli palatini (supplied by CN V3). Please do not reproduce, redistribute or share without the prior express permission of the author.  Hyoid bone  Location:  Inferior to mandible, In anterior neck  Associated with the skull  Only bone in skeleton that does not articulate directly to another bone  Attaches via ligaments to temporal bone, larynx  Composed of:  Body & 2 pairs of horns Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author.  Functions:  Moveable base for tongue  Points of attachment for larynx and neck muscles Sternohyoid, thyrohyoid Please do not reproduce, redistribute or share without the prior express permission of the author. Larynx The larynx or Voice Box, extends from the level of the fourth to the sixth cervical vertebra (C4-C6) Superiorly it attaches to the hyoid bone and opens into the laryngopharynx, inferiorly it continuous with the trachea The larynx consists of four basic anatomic components: cartilaginous skeleton, intrinsic and extrinsic muscles, and mucosal lining. Please do not reproduce, redistribute or share without the prior express permission of the author.  Laryngeal Cartilages  The cartilaginous skeleton, which houses the vocal cords, is comprised of nine cartilages, three unpaired and three paired.  The unpaired cartilages of the larynx are the  thyroid  cricoid  epiglottis.  The paired cartilages of the larynx are the arytenoids, corniculate, and the cuneiforms.  These cartilages are connected to other structures of the head and neck through the extrinsic muscles. Please do not reproduce, redistribute or share without the prior express permission of the author.  Muscles of Larynx  The muscles of the larynx are extrinsic, passing between the larynx and parts around and intrinsic, confined entirely to the larynx. The intrinsic muscles are:  Cricothyreoideus.  Cricoarytænoideus lateralis.  Cricoarytænoideus posterior.  Arytænoideus.  Thyroarytænoideus. Please do not reproduce, redistribute or share without the prior express permission of the author. Intrinsic Muscle of larynx Please do not reproduce, redistribute or share without the prior express permission of the author.  Actions  In considering the actions of the muscles of the larynx, they may be conveniently divided into two groups: 1. Those which open and close the glottis. 2. Those which regulate the degree of tension of the vocal folds. Please do not reproduce, redistribute or share without the prior express permission of the author. The Cricoarytœnoidei posteriores separate the vocal folds, and, consequently, open the glottis, by rotating the arytenoid cartilages The Cricoarytœnoidei laterales close the glottis by rotating the arytenoid cartilages inward, so as to approximate their vocal processes The Arytœnoideus approximates the arytenoid cartilages, and thus closes the opening of the glottis, especially at its back part. Please do not reproduce, redistribute or share without the prior express permission of the author. Nerve supply Vagus and Recurrent laryngeal nerve. Please do not reproduce, redistribute or share without the prior express permission of the author. The functions are: Deglutition (swallowing) Respiration (breathing) Phonation (voice production) Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author.  Trachea The windpipe, or trachea, is an 12 cm long tubular organ , about 2.5 cm in diameter. It descends from the larynx through the neck and into the mediastinum. It ends by dividing into the two main bronchi - primary bronchi. The tracheal wall contains 16 – 20 C shaped rings of hyaline cartilage joined to one another by connective tissues. Please do not reproduce, redistribute or share without the prior express permission of the author. A ridge on the internal aspect of the last tracheal cartilage is called as carina where the trachea branches into two main bronchi. The microscopic structure of the wall of the trachea consists of, - Mucous membrane - Sub mucosa - Adventitia The lining of the trachea prevents the entry of hazardous particles such as dust, pollen, smoke, and other common allergens to enter the airway. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author.  Mechanics of Phonation and Speech  The most complex and highly specialized of the laryngeal functions is sound production. The ability to couple phonation with articulation and resonance allows for human speech.  Sound production requires that several mechanical properties be met. 1. There must be adequate breath support to produce sufficient subglottic pressure. Please do not reproduce, redistribute or share without the prior express permission of the author. 2. There also must be adequate control of the laryngeal musculature to produce not only glottic closure, but also the proper length and tension of the vocal folds. Finally, 3. there must be favorable pliability and vibratory capacity of the tissues of the vocal folds. Once these conditions are met, sound is generated from vocal fold vibration. Please do not reproduce, redistribute or share without the prior express permission of the author.  In general : Phonemes are created when the diaphragm forces air from the lungs into the trachea to produce sound. Most phonemes are voiced and involve the excitation of the vocal chords by periodic pulses of air created by the glottis. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Q&A Session Please do not reproduce, redistribute or share without the prior express permission of the author.  Thank you Address Telephone Website Lot 33-40, Blok C, Plaza Juta, +6088 431 025/35 kk.cyberjaya.edu.my KM 7.2 Off Jalan Tuaran, 88400 Likas, Kota Kinabalu, Email Sabah, Malaysia [email protected]