Dr. Sujan Singh Chhetri

Upper aerodigestive tract serves the functions of respiration, swallowing and speech Pharynx is conical fibromuscular tube forming upper part of air and food passages Is cm long, extending from base of skull to lower border of cricoid cartilage

Nasopharynx: – Upper deep cervical, retropharyngeal, parapharyngeal, spinal accessory chain (posterior triangle) – May cross midline to drain into contralateral lymph node Oropharynx: – Jugulodigastric, retropharyngeal, parapharyngeal – Base of tongue drain bilaterally Hypopharynx: – Deep cervical, parapharyngeal,paratracheal,supraclavicular – Pyriform fossa richly supplied with lymphatics

Single (3)Paired (3) EpiglottisArytenoid ThyroidCorniculate (Santorini) CricoidCuneiform (Wrisberg) Elastic: Epiglottis, corniculate, cuneiform & apex of arytenoid. Little or no calcification Hyaline: Thyroid, cricoid & remaining arytenoid. Calcify as age advances Ossification begins by yr & is completed by 60 yr

Thyrohyoid membrane Hyoepiglottic ligament Cricothyroid membrane Cricotracheal ligament

Acting on vocal cords – Abduction: Posterior cricoarytenoid – Adduction: Lateral cricoarytenoid, Transverse inter- arytenoid, Thyroarytenoid externa – Tensors: Cricothyroid – Relaxation + shortening: Vocalis

Primary ElevatorsSecondary Elevators  Stylopharyngeus  Mylohyoid  Salpingopharyngeus  Stylohyoid  Palatopharyngeus  Geniohyoid  Thyrohyoid  Digastric Depressors  Sternohyoid  Sternothyroid  Omohyoid

Superior Laryngeal Nerve: Internal: sensation to supraglottis & glottis External: motor to cricothyroid muscle Recurrent Laryngeal Nerve: sensation to subglottis motor to all intrinsic muscles but cricothyroid

Supraglottis: via thyrohyoid membrane into upper deep cervical nodes Subglottis: via cricothyroid membrane into pretracheal, prelaryngeal, lower deep cervical nodes, mediastinum Glottis: no lymphatics

Supraglottis: laryngeal inlet to apex of ventricle Glottis: apex of ventricle to 10 mm below Subglottis: lower glottic border to lower cricoid border

Supraglottis: – Supra hyoid epiglottis – Aryepiglottic folds – Arytenoids – Ventricular bands – Infra hyoid epiglottis Glottis: – True vocal cords – Anterior commissure – Posterior commissure Subglottis

Positioned high (C3-C4) Conical in shape & subglottis is narrowest part Moves higher during swallowing allowing simultaneous breathing & feeding Loose sub-mucosal tissues (swell up easily) Soft cartilages that collapse easily

1.Protection of lower airway 2.Phonation 3.Respiration 4.Chest fixation

Sphincteric closure of laryngeal opening – Laryngeal inlet (aryepiglottic folds) – False cords – True cords

Cessation of respiration – Temporarily through reflex generated by afferent fibres of CN IX, when food comes in contact with posterior pharyngeal wall or the base of tongue Cough reflex – To dislodge & expel foreign particle when it comes into contact with respiratory mucosa

Voice is produced by the following mechanism – Aerodynamic myoelastic theory – Neuro-chronaxic theory

Requirements of normal phonation are: 1.Active respiratory support 2.Adequate glottic closure 3.Normal mucosal covering of the vocal cord 4.Adequate control of vocal fold length and tension

Vocal cords adducted Infraglottic air pressure generated from lungs Air force open the cords and is released as small puffs, vibrate vocal cords and produce sound which is amplified by mouth, pharynx, nose & chest This sound is converted into speech by the modulatory action of lips, tongue, palate, pharynx & teeth

Vocal folds are completely closed as subglottal pressure builds up, Lower lips separate due to rising subglottal pressure (OPEN PHASE)

Only the upper lips are in contact, puff of air is released as the vocal folds separate completely

Elastic recoil of vocal folds, Bernoulli’s forces, result lower lips of vocal folds drawing inward. mucosal wave is propagated superiolaterally. (CLOSED PHASE)

Airflow reduced, lower lips are completely approximated, free edge of vocal folds come into contact from inferiorly to superiorly. New glottic cycle begins

Vibration of vocal fold muscles due to impulses generated from recurrent laryngeal nerves. Speed is regulated by acoustic center in brain. Obsolete theory

1.Oral stage (lasts for 1 second, voluntary)  Preparatory phase  Propulsive phase 2.Pharyngeal Stage (1 second, involuntary) 3.Oesophageal Stage (8-20 seconds)

Solid food chewed, lubricated with saliva & converted to a bolus Requires coordinated movement of lips, cheeks, jaws & tongue against a closed oropharyngeal isthmus

Food bolus propelled backwards by pressing of tongue against hard palate Approximation of tongue against hard palate starts with tip of tongue & moves back Stage ends when food bolus crosses anterior tonsillar pillar

1. Nasopharyngeal isthmus closed: soft palate touches Passavant’s ridge 2. Oropharyngeal isthmus closed: tongue base touches palate 3. Elevation of larynx: negative pressure in hypopharyngeal lumen (suction pump)

4. Closure of larynx: – True vocal cords approximate – False cords approximate – Ary-epiglottic folds approximate – Temporary cessation of respiration – Epiglottis falls back over larynx inlet

5.Posterior retraction of base tongue: tongue driving force 6.Pharyngeal constrictors contract 7.Elevation of pharynx 8.Opening of cricopharyngeal sphincter

1.Closing of cricopharyngeal sphincter 2.Opening & descent of larynx 3. Primary peristalsis: large amplitude, propulsive 4. Secondary peristalsis: small amplitude, propulsive, for food remnants 5. Relaxation of lower esophageal sphincter: food bolus enters stomach