Upper Respiratory Tract

Upper Respiratory Tract

Lectures Objectives Describe the structure of nasal cavity including nasal septum. Describe the structure of lateral wall of nasal cavity including conchae and meatuses. Locate the openings of the paranasal air sinuses and naso lacrimal duct in the meatuses. Describe nasal innervations, blood supply, and its relation to epistaxis. Study the structure of nasopharynx and associated openings with their clinical importance. Describe the structure of various cartilages and membranes of the larynx. Describe muscles of the larynx including their action, nerve and blood supply. Describe the structure of vocal cords and the mechanism of voice production and control of air passageway.

Nose

Nose External nose portion visible on face Internal nose large cavity beyond nasal vestibule Internal nares or choanae Ducts from paranasal sinuses and nasolacrimal ducts open into internal nose Nasal cavity divided by nasal septum Nasal conchae subdivide cavity into meatuses Increase surface area and prevents dehydration Olfactory receptors in olfactory epithelium

Parts Root Dorsum Apex Naris (nostrils, anterior nasal apertures) Ala External Nose

External Nose Skeleton of the nose Bony part Frontal, nasal, maxillary bones Cartilaginous part Lateral, septal, alar cartilages Blood supply: branches of ophthalmic, maxillary & facial aa. Nerve supply Infratrochlear (V1) External nasal (V1) Infraorbital (V2)

Nasal septum Bony part Perpendicular plate of ethmoid Vomer Cartilaginous part Septal cartilage

Parts Nasal vestibule Nasal septum Choanae (posterior nasal apertures) Walls of the nasal cavity Floor Roof Lateral wall Sphenoethmoidal recess Nasal conchae Superior, middle, & inferior Meatuses Superior, middle, & inferior Nasal Cavity

Sphenoethmoidal recess Sphenoid sinus Meatuses Superior Posterior ethmoid sinus Middle Bulla ethmoidalis Middle ethmoid sinus Hiatus semilunaris Maxillary sinus Infundibulum Frontal sinus Anterior ethmoid sinus Inferior Nasolacrimal duct Nasal Meatuses

Paranasal Sinuses Paired cavities in ethmoid, sphenoid, frontal and maxillary bones Lined with mucous membranes and open into nasal cavity Resonating chambers for voice, lighten the skull Sinusitis is inflammation of the membrane

Paranasal Sinuses Maxillary sinus Between floor of orbit and roots of upper molars and premolars Superior alveolar nn. (V2) Frontal sinus Supraorbital nn. (V1) Sphenoid sinus Body of sphenoid Posterior ethmoidal nn. (V1) Ethmoid sinus Anterior, middle & posterior Between nasal cavity and orbit Anterior & posterior ethmoidal nn. From nasociliary n. (V1)

Paranasal Sinuses: X ray

Nasal Cavity: Innervation Olfactory nerve Trigeminal nerve Ophthalmic Maxillary

Nasal Cavity: Blood Supply Anterior & posterior ethmoidal aa. From ophthalmic a. Sphenopalatine a. From maxillary a. Septal branch from facial a. Kiesselbach s area & plexus Epistaxis Lymph drainage Deep cervical lymph nodes Vestibule submandibular lymph nodes

Pharynx

Pharynx Muscular tube (5 inch long) hanging from skull Skeletal muscle & mucous membrane Completed posteriorly & deficient anteriorly (openings into nose, mouth & larynx) Extends from internal nares to cricoid cartilage (C6) Funnel shape wide superiorly & narrow inferiorly (1.5 cm) Functions Passageway for food and air Resonating chamber for speech production Tonsil (lymphatic tissue) in the walls protects entryway into body

Regions of the Pharynx Distinct regions nasopharynx, oropharynx and laryngopharynx

Nasopharynx Above soft palate Openings Internal nares Pharyngeal isthmus Auditory (Eustachian, pharyngotympanic) tube Structures Pharyngeal tonsil (adenoids) Tubal elevation Tubal tonsils Salpingopharyngeal fold Salpingopharyngeus m. Pharyngeal recess

Oropharynx From soft palate to epiglottis Structures At floor Posterior ⅓ of tongue Lingual tonsils Median glossoepiglotic fold Lateral glossoepiglotic folds Valleculae

Oropharynx At lateral wall Palatoglossal fold Palatoglossus m. Oropharyngeal isthmus Palatopharyngeal fold Palatopharyngeus m. Palatine tonsil

Laryngopharynx Extends from epiglottis to cricoid cartilage Posterior to laryngeal inlet Piriform fossa Between aryepiglotic fold and thyroid cartilage

Pharyngeal Muscles External circular muscles Inserts into the pharyngeal raphe Superior, middle, & inferior constrictor mm. Overlap each other (inferior is more superficial) Cricopharyngeus m. Lower end Sphincter Internal longitudinal muscles Stylopharyngeus m. Palatopharengeus m. Salpingopharyngeus m. Nerve supply: pharyngeal plexus except stylopharyngeus muscle (IX)

Pharynx Sensory innervation Nasopharynx (V2) Oropharynx (IX) Laryngopharynx (X) internal laryngeal nerve Blood supply Ascending pharyngeal aa. Tonsillar branch of facial aa. Branches of maxillary & lingual aa. Lymph drainage Deep cervical nodes Retropharyngeal or paratracheal nodes deep cervical

Cartilage & connective tissue tube Below hyoid bone Anterior to C4 to C6 Short passageway connecting laryngopharynx with trachea Constructed of 3 single & 3 paired cartilages Functions Passageway for air Voice production Prevent entrance of food Larynx

Larynx Relations Infrahyoid mm. Thyroid gland Major blood vessels

Larynx: Cartilages

Thyroid cartilage The largest Incomplete ring Laminae Laryngeal prominence (Adam s apple) Oblique line Superior & inferior cornua Cricothyroid joints Larynx: Cartilages

Larynx: Cartilages Cricoid cartilage Complete ring Below thyroid cartilage Lamina (posteriorly) Cricoarytenoid joints Arch (anteriorly) Arytenoid cartilages Apex, base, vocal process, & muscular process

Epiglottis Leaf shape cartilage (elastic cartilage) Stalk attached to thyroid cartilage Aryepiglottic fold Median and lateral glossoepiglottic folds valleculae Larynx: Cartilages

Larynx: Cartilages Corniculate cartilages Above arytenoids (attachment of aryepiglottic fold) Cuneiform cartilages In the aryepiglottic fold (support)

Larynx: Membranes & Ligaments Thyrohyoid membrane Median thyrohyoid ligament Cricotracheal ligament Quadrangular membrane Between epiglottis & arytenoid Vestibular ligament (inferior margin) Vestibular fold Immovable, vascular (pinkish) Cricothyroid ligament Vocal ligament (superior margin) Vocal fold Mobile, avascular (whitish) Rima glottidis (glottis)

Larynx: Cavity Inlet of larynx Orientation Boundaries Vestibule Between inlet & vestibular folds Middle region Between laryngeal folds Laryngeal sinus (ventricle) Laryngeal saccule Lower region (infraglottic cavity) Between vocal folds & lower border of cricoid

Extrinsic muscles Larynx: Muscles Elevators Suprahyoids (Digastric, stylohyoid, mylohyoid, & geniohyoid) Longitudinal pharyngeal (stylopharyngeus, salpingopharyngeus, & palatopharyngeus) Depressors (infrahyoid) Sternothyroid, sternohyoid, & omohyoid

Larynx: Muscles Intrinsic muscles Modification of laryngeal inlet Narrowing Oblique arytenoid m. Widening Thyroepiglottic m. Movement of vocal cords Tensing Cricothyroid m. Relaxing Thyroarytenoids (vocalis) m. Adducting Lateral cricoarytenoid m. Abducting Posterior cricoarytenoid m. Approximating aretyneoids Transverse arytenoid m.

Larynx: Muscles

Voice Production Vocal folds are adducted Muscle contraction pulls elastic ligaments which stretch vocal folds out into airway Vibrate and produce sound with released air (frequency or pitch) Folds can move apart or together, elongate or shorten, tighter or looser Androgens make folds thicker and longer slower vibration and lower pitch Quality of voice determined by other structures (mouth, lips, tongue, pharynx, soft palate, & teeth)

Nerve supply Sensory innervation (X) Above vocal cords: internal laryngeal n. Below vocal cords: recurrent laryngeal. Motor innervation All intrinsic muscles innervated by recurrent laryngeal except cricothyroid muscle (external laryngeal n.) Blood supply Upper half: superior laryngeal branch of superior thyroid a. Lower half: inferior laryngeal branch of the inferior thyroid a. Lymph drainage Deep cervical nodes Larynx