Respiratory System Part-2 ANAT 211, 212, 213 2023-24 PDF

Respiratory System Part-2 Anatomy Course ANAT 211, 212 and 213 Term 2, 2023-24 Basic Sciences Department, COSHP, KSAU-HS, KSA Respiratory System-2 By the end of this session the student should be able to: Discuss the anatomy of pharynx (parts and their extent, important structures, communications)....

Respiratory System Part-2 Anatomy Course ANAT 211, 212 and 213 Term 2, 2023-24 Basic Sciences Department, COSHP, KSAU-HS, KSA Respiratory System-2 By the end of this session the student should be able to: Discuss the anatomy of pharynx (parts and their extent, important structures, communications). The Pharynx It is a fibro-muscular tube that extends from the base of skull to its continuation into the esophagus Its anterior wall is deficient through which the pharynx communicates with: The nasal cavity, The oral cavity The larynx Mucous membrane of pharynx is continuous with the nose, mouth, larynx and middle ear. Therefore, the infection of any one organ can spread easily to others. Pharynx has the following parts: 1. Nasopharynx 2. Oropharynx 3. Laryngopharynx 1. Nasopharynx It lies posterior to the nasal cavities above the soft palate. It always remains patent to allow access to inhaled air. Extention: Superior- sphenoid bone, Inferior- margins of soft palate and Uvula Anterior- nasal septum and choana, posterior Posterolateral- pharyngeal wall Important structures: 1. Pharyngeal tonsils (adenoids) 2. Tubal tonsils 3. Opening of the internal auditory (Eustachian) tubes 4. Pharyngeal recess 5. Muscles of pharyngeal wall 1. Tensor veli palatini 2. Levator veli palatini 3. Salpingopharyngeus Communicates: inferiorly with the oropharynx. 2. Oropharynx The oropharynx opens anteriorly into the mouth. Extension: Superior- margins of soft palate and uvula, Inferior- the superior border of epiglottis, Anterior- 1/3rd of the tongue up to sulcus terminalis Posterolateral- pharyngeal wall of oropharynx. Important structures: laterally located two folds of mucous membrane developed due to underlying muscles. Anterior fold- by palato-glossus muscle and posterior fold by Palato-pharyngeus muscle. They are also called as anterior and posterior pillars or arches. Between the two arches lie the palatine tonsils. Muscles of oropharynx 1. Palatoglossus 2. Palatopharyngeus 3. Superior constrictor Communication: inferiorly with the laryngopharynx. 3. Laryngopharynx Extension: Superior- from superior border of epiglottis. Inferior- cricoid cartilage. Anterior- posterior to laryngeal inlet vallecula and larynx. Posterolateral- laryngeal pharyngeal wall. Important structure: Posterolateral wall contains inner Palatopharyngeus and stylopharyngeus, and out middle and inferior constrictors. Laryngeal inlet- bounded by aryepiglottic fold. Piriform recess- space beside the larynx. Communication: The laryngopharynx faces Anteriorly: with laryngeal inlet and lower posterior surface of larynx and Inferiorly is continuous with the esophagus. Muscles of Pharynx The pharynx has intrinsic and extrinsic muscles. A- Intrinsic muscles: 1. The intrinsic muscles form the posterolateral wall of the pharynx. 2. They are deficient anteriorly, communicating with nasal cavity, oral cavity and larynx. The intrinsic muscle layer are primarily three constrictors: 1. Superior constrictor 2. Middle constrictor 3. Inferior constrictor Muscles of Pharynx B- Extrinsic muscles: The extrinsic muscles consist of three muscles 1. Palatopharyngeus attached to soft palate. 2. Salpingopharyngeus attached to auditory tube. 3. Stylopharyngeus attached to styloid process. These muscles arise outside the pharyngeal muscular wall, come inside to attach internally to pharyngeal wall of constrictor muscles. Nerve Supply A- Motor: All pharyngeal muscles are supplied by CN X (vagus) via pharyngeal plexus EXCEPT stylopharyngeus which is supplied by CN IX (glossopharyngeal) B- Sensory: 1. Nasopharynx is supplied by pharyngeal branch of maxillary nerve from CN V 2. Oropharynx is supplied by CN IX through pharyngeal plexus 3. Laryngopharynx is supplied by CN X through pharyngeal plexus C- Parasympathetic : from pterygopalatine ganglion through pharyngeal branches of maxillary nerve