Throat Anatomy, Physiology and Common Conditions
DCM 2203 · Ear, Nose and Throat Care · LWA 4: Throat Throat anatomy and physiology link breathing, swallowing, speech and protection of the lower airway. These notes cover the pharynx, larynx and upper oesophagus; the mechanics of deglutition and voice; clinical assessment; pharyngitis and adenotonsillitis; laryngitis; deep-neck infection; branchial cysts; laryngeal stenosis and trauma; foreign bodies; upper-airway obstruction; and caustic injury. Learning outcomes: Describe the divisions and important structures of the pharynx and larynx; explain swallowing and phonation; define common throat symptoms; take a focused history and perform a safe examination; identify common inflammatory, congenital, traumatic and obstructive disorders; outline first priorities in airway emergencies; and recognise when urgent ENT or hospital referral is needed. Airway warning: Stridor at rest, severe work of breathing, drooling or inability to swallow saliva, cyanosis, rapidly worsening voice or breathing, tripod positioning, reduced air entry, altered consciousness, or a sudden choking episode can signal a time-critical airway emergency. Call for urgent senior, anaesthetic and ENT help and arrange transfer to a facility able to manage the airway. Keep the person calm and in their position of comfort. In a distressed child with possible epiglottitis or severe obstruction, do not force the child to lie down, repeatedly examine the throat, or send for investigations before the airway team has assessed them. Clinical principle: Assess airway and breathing before investigating the throat. A patient can deteriorate quickly when a narrowed airway is further upset by crying, unnecessary handling, sedation or poorly planned examination. In this guide Scope and key terms Pharyngeal anatomy Laryngeal anatomy Swallowing, airway protection and voice Clinical assessment and investigations Pharyngitis and adenotonsillitis Quinsy and deep-neck infection Laryngitis and hoarseness Upper-airway obstruction Throat and oesophageal foreign bodies Throat and laryngeal trauma Branchial cleft cysts and neck masses Laryngeal stenosis Caustic ingestion Red flags and referral Cases and self-check References 1. Scope and key terms The throat is a shared passage and functional region rather than one single organ. It conducts air toward the larynx and trachea, passes food and liquid from the mouth into the oesophagus, contributes to immune defence, and participates in resonance, articulation and voice. Symptoms can arise from infection, allergy, trauma, a foreign body, congenital abnormality, reflux, neuromuscular dysfunction or a mass. Term Meaning Clinical clue Dysphagia Difficulty initiating or completing swallowing, or a sensation that food sticks during its passage. Coughing or choking with liquids suggests impaired airway protection; progressive solid-food difficulty needs evaluation. Odynophagia Pain on swallowing. Can accompany acute inflammation, ulceration, trauma or a lodged object. Dysphonia Abnormal voice quality, pitch, loudness or effort. Hoarseness that persists or occurs with a neck lump, weight loss, blood or breathing difficulty needs assessment. Stridor Harsh, usually high-pitched sound from turbulent airflow through a narrowed upper airway. Stridor at rest, especially with work of breathing or reduced air entry, is an emergency sign. Stertor Low-pitched snoring or rattling sound from obstruction around the nose or pharynx. Assess consciousness, secretions and airway patency. Globus Persistent lump sensation in the throat, often without impaired passage of food or liquid. Clarify whether there is true dysphagia, pain, weight loss, aspiration or a mass. 2. Pharyngeal anatomy The pharynx is a fibromuscular tube extending from the base of the skull to the lower border of the cricoid cartilage, where it continues as the oesophagus. It lies behind the nasal cavity, mouth and larynx, and is conventionally divided into three regions. Region Boundaries and landmarks Clinical importance Nasopharynx Behind the nasal cavity and above the soft palate; contains the opening of each auditory tube and the pharyngeal tonsil (adenoid). Adenoid enlargement can obstruct nasal airflow and contribute to mouth breathing, hyponasal speech, sleep-disordered breathing and middle-ear ventilation problems. Oropharynx Behind the oral cavity, from the soft palate to the upper epiglottis; includes the tonsillar fossae, palatine tonsils, posterior tongue and posterior pharyngeal wall. Common site of pharyngitis, tonsillitis, peritonsillar abscess and lodged sharp food bones. Laryngopharynx (hypopharynx) Behind and beside the larynx, from the upper epiglottis to the lower cricoid; includes the piriform fossae. Food and liquid are channelled toward the oesophageal inlet. A foreign body or lesion here can threaten both swallowing and airway function. Waldeyer’s lymphatic ring Lymphoid tissue forms a protective ring around the entrance to the respiratory and digestive tracts. Its main components are the pharyngeal tonsil (adenoid), paired tubal tonsils, paired palatine tonsils and lingual tonsil. This tissue samples inhaled and swallowed antigens. Recurrent infection or adenoid and tonsil enlargement can cause symptoms, but enlarged tissue should be interpreted alongside age, sleep, breathing, swallowing and infection history. Muscles, nerve supply and lymph drainage Circular pharyngeal constrictor muscles propel a swallowed bolus downward, while longitudinal muscles elevate and shorten the pharynx during swallowing. Most pharyngeal motor supply travels through the vagal pharyngeal plexus; the stylopharyngeus is supplied by the glossopharyngeal nerve. Sensation is regionally supplied by branches of the trigeminal nerve in the nasopharynx, glossopharyngeal nerve in much of the oropharynx, and vagal branches in the laryngopharynx. Tonsillar and pharyngeal inflammation may produce tender upper cervical lymph nodes. A persistent, firm or enlarging neck node requires assessment rather than repeated empirical treatment. 3. Laryngeal anatomy The larynx sits between the pharynx and trachea in the anterior neck. Its framework includes the thyroid and cricoid cartilages, epiglottis and paired arytenoid cartilages, joined by ligaments and moved by intrinsic and extrinsic muscles. The cricoid is a complete ring; swelling or injury within the relatively narrow paediatric airway can therefore have a substantial effect on airflow. Supraglottis: structures above the true vocal folds, including the epiglottis and aryepiglottic folds. Glottis: the true vocal folds and the opening between them (rima glottidis). Subglottis: the airway below the vocal folds, extending to the lower border of the cricoid. False vocal folds: vestibular folds above the true folds; they help close and protect the laryngeal inlet. The larynx protects the lower airway during swallowing, allows controlled passage of air, generates voice through vocal-fold vibration, and produces an effective cough. The recurrent laryngeal nerves supply most
