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.

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.

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.

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.

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 intrinsic laryngeal muscles and sensation below the vocal folds. The internal branch of the superior laryngeal nerve carries sensation above the folds; its external branch supplies the cricothyroid muscle, which adjusts vocal-fold tension and pitch. Nerve injury may cause hoarseness, weak cough, aspiration or breathing difficulty depending on which structures are affected.

4. Swallowing, airway protection and voice

Three phases of swallowing

1. Oral preparatory and oral transport phases: food is chewed and mixed with saliva, formed into a bolus, then pushed backward by the tongue. This phase is largely voluntary.
2. Pharyngeal phase: sensory input triggers a coordinated reflex. The soft palate closes the nasopharynx; the larynx elevates and moves forward; vocal folds and laryngeal inlet close; breathing briefly pauses; pharyngeal muscles propel the bolus toward the upper oesophageal sphincter. Poor coordination can send food or liquid into the airway.
3. Oesophageal phase: peristaltic contractions carry the bolus down the oesophagus toward the stomach after the upper oesophageal sphincter relaxes and closes again.

Normal airway protection depends on alertness, sensation, laryngeal closure, a coordinated swallow and an effective cough. Ask whether difficulty starts when initiating a swallow or whether food feels stuck after swallowing; whether solids, liquids or both are affected; and whether there is coughing, choking, wet voice, nasal regurgitation, recurrent chest infection, dehydration or weight loss.

How voice is produced

Air expelled from the lungs sets the apposed true vocal folds into vibration. Pitch is influenced by vocal-fold length, tension and mass; loudness depends in part on airflow and vibratory amplitude. The pharynx, mouth, tongue, lips and nasal cavities shape the sound into recognisable speech. Voice can be changed by inflammation, vocal overuse, smoking, reflux, nerve injury, a structural lesion or tumour. Hoarseness is a symptom and should be assessed in context.

5. Clinical assessment and investigations

Focused history

• Establish onset, speed of progression and duration. Sudden choking differs from a gradual sore throat or months of progressive dysphagia.
• Ask about fever, painful swallowing, ability to swallow saliva, drooling, voice change, stridor, breathlessness, cough, choking, aspiration and sleep-related breathing symptoms.
• Clarify whether swallowing difficulty affects liquids, solids or both; whether it is oropharyngeal (difficulty initiating) or oesophageal (food sticks after initiation); and whether symptoms are progressive, intermittent or associated with regurgitation.
• Ask about contact with respiratory infections, vaccination history when relevant, recurrent tonsillitis, dental infection, trauma, foreign-body ingestion, caustic exposure, surgery, intubation, tobacco, alcohol, occupational voice use and medicines.
• Ask about weight loss, blood in saliva, referred ear pain, persistent neck lump, night sweats, dehydration, immunosuppression and prior cancer.

Safe examination

1. Observe from the doorway: posture, ability to speak or cry, alertness, colour, respiratory effort, stridor or stertor, drooling, audible voice change and ability to manage secretions.
2. Assess airway, breathing and circulation first when the patient appears unwell. Keep a child with respiratory distress with their caregiver and in a comfortable position. Avoid upsetting or laying down a patient with suspected upper-airway obstruction.
3. In a stable cooperative patient, inspect the mouth with a light: lips, teeth, tongue, floor of mouth, palate, tonsils and posterior pharynx. Note asymmetry, exudate, ulceration, membranes, bulging, pooling of secretions, foreign material and the position of the uvula. Do not scrape a firmly adherent membrane.
4. Examine the neck for tenderness, swelling, lymph nodes, tracheal position, skin injury and range of movement. A toxic patient with drooling, trismus, torticollis, neck swelling or stridor needs urgent escalation.
5. Test voice and, only when safe, observe a swallow. Stop if coughing, choking, breathing difficulty or aspiration is suspected. Do not conduct a water-swallow test in a patient with threatened airway or impaired consciousness.

Choosing investigations

Investigations should answer a clinical question and must not delay stabilisation or urgent transfer. Depending on presentation and local capacity, options include a throat swab or rapid pathogen test when it will change treatment, full blood count or inflammatory markers for selected complicated illness, flexible naso-laryngoscopy in a stable patient, neck or chest radiography for a suspected object or structural problem, and contrast CT for selected deep-neck infection or mass evaluation. Imaging can be falsely reassuring and should not postpone airway management when obstruction is suspected. Direct laryngoscopy, biopsy, airway endoscopy and removal of an impacted object are specialist procedures performed with appropriate equipment, monitoring and airway support.

6. Pharyngitis and adenotonsillitis

Pharyngitis is inflammation of the pharynx; tonsillitis is inflammation of the palatine tonsils; adenotonsillitis involves both adenoid and tonsillar lymphoid tissue. Viral respiratory infections are common causes of acute sore throat. Bacterial causes, including Group A streptococcus, are clinically important in the appropriate context. Other differentials include infectious mononucleosis, oral candidiasis, diphtheria, peritonsillar abscess, epiglottitis, dental infection, allergy, reflux, trauma and malignancy.

Clinical features and assessment

Symptoms may include sore throat, fever, painful swallowing, enlarged or exudative tonsils, tender cervical nodes, headache, fatigue, cough, coryza, conjunctivitis or hoarseness. A cough and coryza often accompany viral illness, but no single feature reliably identifies every cause. Consider a pseudomembrane, especially a tough grey membrane with systemic illness, as a serious finding: do not scrape it; use appropriate infection-control precautions and urgently follow national guidance for suspected diphtheria. In a child, ask about nasal obstruction, mouth breathing, snoring, pauses in breathing, hearing problems and recurrent episodes when adenoid enlargement is suspected.

Management principles

• Assess hydration, airway, ability to swallow and systemic severity. Provide supportive care and analgesia appropriate to age, comorbidities and the Uganda Clinical Guidelines.
• Do not prescribe antibiotics automatically for every sore throat. Many cases are viral; antibiotic choice and duration should follow the current Uganda national guideline, local resistance patterns and clinician assessment. Avoid using antibiotics to treat a viral illness.
• Encourage fluids when swallowing is safe, rest, and infection-control measures such as hand hygiene and respiratory etiquette. Give a clear plan for reassessment if symptoms worsen or fail to improve.
• Recurrent severe tonsillitis, obstructive sleep symptoms, persistent unilateral tonsillar enlargement, an atypical ulcer or mass, or suspected malignancy warrants ENT assessment. The decision about adenoidectomy or tonsillectomy depends on documented disease burden, obstruction, complications, age and specialist evaluation.

Complications to recognise

Peritonsillar abscess (quinsy), parapharyngeal or retropharyngeal infection, dehydration and airway obstruction are urgent complications. Streptococcal infection may be associated with acute rheumatic fever or post-streptococcal glomerulonephritis. New joint symptoms, cardiorespiratory symptoms, dark or reduced urine, facial puffiness or hypertension after a throat infection require medical evaluation.

7. Quinsy and deep-neck infection

A peritonsillar abscess forms in the tissue around a tonsil and often follows tonsillitis. Typical features are severe unilateral throat pain, painful swallowing, trismus, muffled “hot-potato” voice, drooling, asymmetrical palatal or tonsillar swelling and deviation of the uvula away from the affected side. A patient may have difficulty drinking and may appear systemically unwell. Urgent same-day ENT or hospital assessment is needed; airway status, hydration, sepsis risk and the need for drainage or antimicrobial treatment are determined by the treating team.

Retropharyngeal infection is particularly important in young children and may present with fever, neck pain or stiffness, torticollis, dysphagia, drooling, posterior pharyngeal swelling, muffled voice or respiratory distress. Parapharyngeal infection can cause neck swelling, trismus, fever and displacement of the pharyngeal wall. Ludwig angina is a rapidly spreading infection of the floor of the mouth and submandibular spaces, commonly related to dental infection; a raised tongue, firm floor of mouth, drooling or breathing difficulty signals imminent airway danger.

8. Laryngitis and hoarseness

Laryngitis is inflammation of the larynx and commonly presents with hoarseness, a rough or weak voice, voice fatigue, throat irritation, dry cough or temporary voice loss. Acute laryngitis often accompanies a viral upper-respiratory infection or follows voice overuse. Other causes of persistent hoarseness include smoking, reflux, allergy, inhaled irritants, vocal-fold lesions, vocal-fold paralysis, trauma and laryngeal cancer.

Assessment and care

Ask about duration and progression, voice demands, smoking and alcohol exposure, recent intubation or neck surgery, reflux symptoms, aspiration, pain, blood, weight loss, neck mass and breathing difficulty. Many uncomplicated acute episodes improve with supportive care, hydration and reduced vocal strain. Do not whisper forcefully or shout; both can strain the voice. Antibiotics are not routinely helpful for a presumed viral cause. Persistent or recurrent hoarseness, especially with tobacco exposure, a neck mass, swallowing difficulty, blood, unexplained weight loss or prior neck/chest surgery, warrants laryngeal visualisation and ENT review. Stridor or respiratory difficulty needs urgent assessment.

9. Upper-airway obstruction

Upper-airway obstruction can occur at the nose, pharynx, supraglottis, glottis, subglottis or trachea. Causes include infection and inflammation (croup, epiglottitis, bacterial tracheitis, tonsillar or deep-neck infection), foreign body, anaphylaxis or angio-oedema, trauma or burns, reduced consciousness, congenital narrowing and a mass. Young children can deteriorate with relatively modest swelling because their airways are smaller.

Recognise severity

• Early or moderate warning signs: noisy breathing, stridor, nasal flaring, tachypnoea, suprasternal or intercostal recession, prolonged inspiration, agitation, difficulty speaking or feeding, drooling or reduced air entry.
• Severe or late signs: exhaustion, drowsiness, cyanosis, slow or irregular breathing, markedly reduced air movement, a quieter stridor despite worsening effort, or collapse. A quiet chest or fading stridor in a deteriorating patient is not reassurance.
• Possible epiglottitis: abrupt severe sore throat, fever, toxic appearance, difficulty swallowing, drooling, muffled voice, preferred upright or forward-leaning posture and stridor, sometimes without the barking cough typical of croup. It is an airway emergency.
• Possible inhaled foreign body: sudden cough, choking or gagging during eating or play, often in a young child; the event may be unwitnessed and the patient may have a persistent cough, wheeze or one-sided reduction in breath sounds afterward.

Immediate priorities

1. Call for senior clinical, anaesthetic and ENT support early; activate emergency response and plan transfer if airway expertise is not available.
2. Allow the person to remain calm in the position that best supports breathing. Keep a caregiver close to a distressed child. Avoid unnecessary examination, agitation, sedation, lying flat or separation from the caregiver.
3. Assess airway, breathing and circulation; provide oxygen if indicated and tolerated while preparing for definitive care. Oxygen can support oxygenation but does not remove a mechanical obstruction.
4. Do not attempt intubation, surgical airway, forceful throat examination or foreign-body extraction unless trained, equipped and supported under an emergency airway plan.
5. Treat the cause under the current Uganda guideline and facility protocol. The airway team decides whether airway intervention, medication, endoscopy, imaging or surgery is required.

10. Throat and oesophageal foreign bodies

Foreign bodies may lodge in the tonsil, pharynx, larynx, trachea or oesophagus. A child may have sudden gagging, choking, cough, drooling, dysphagia, refusal to feed or unexplained noisy breathing. Adults may report a fish bone or food bolus stuck after a meal. Distinguish an airway foreign body (breathing or ventilation is affected) from an oesophageal foreign body (swallowing is painful or blocked but breathing may initially be preserved); either can become an emergency.

• Activate emergency response for choking with inability to speak, breathe or cough effectively; use age-appropriate foreign-body airway obstruction first aid if trained, and follow local resuscitation guidance.
• Do not perform blind finger sweeps or push an object deeper. Remove an object from the visible mouth only if it is clearly seen and can be safely grasped without pushing it back.
• Drooling or inability to swallow saliva, respiratory symptoms, a sharp object such as a fish bone, an oesophageal button battery, multiple magnets, or a complete food-bolus obstruction needs urgent specialist assessment. Button batteries can cause rapid tissue injury.
• Do not give food to push an object down, induce vomiting or delay assessment while trying repeated home remedies. The clinical team chooses imaging and endoscopic or other removal according to the object, site, symptoms and local expertise.

11. Throat and laryngeal trauma

Blunt or penetrating neck trauma, strangulation, foreign-body injury, inhaled heat or chemicals, and complications of intubation or surgery can injure the pharynx, larynx, trachea or oesophagus. Red flags include hoarseness after trauma, stridor, painful or difficult swallowing, coughing blood, neck swelling or bruising, subcutaneous air, air escaping from a wound, rapidly increasing pain, breathing difficulty or abnormal neck contour.

Prioritise airway, breathing, circulation and cervical-spine precautions when indicated. Visible external injury may underestimate internal damage, and airway swelling can progress. Do not blindly probe a penetrating wound or remove an embedded object. Avoid oral intake when a pharyngeal or oesophageal injury is suspected. Arrange urgent hospital and ENT/trauma assessment; imaging and endoscopy are selected after airway stability is considered.

12. Branchial cleft cysts and neck masses

Branchial cleft anomalies arise from persistence of embryological structures along the side of the neck. A second branchial cleft cyst commonly presents as a soft, usually painless lateral neck swelling near the anterior border of the sternocleidomastoid muscle; a sinus or fistula may drain through a small skin opening. Infection can cause rapid enlargement, pain, redness, fever or difficulty swallowing. Other congenital midline neck swellings, such as thyroglossal duct cysts, have different locations and movement characteristics.

A neck lump should not be assumed to be a congenital cyst without assessment. Consider reactive lymph nodes, tuberculosis, thyroid disease, salivary-gland disease, abscess, lymphoma and metastatic cancer in the differential. An adult with a persistent lateral neck mass, a hard or fixed lesion, ulceration, unexplained weight loss, referred ear pain, hoarseness or dysphagia needs prompt ENT evaluation. Ultrasound or other imaging, needle sampling and definitive management are planned by the clinician; avoid repeated empirical antibiotics without a clear indication.

13. Laryngeal stenosis

Laryngeal stenosis is narrowing of the laryngeal airway. It may be congenital or acquired after prolonged intubation, airway trauma, infection, surgery, radiation or inflammatory disease. Symptoms depend on the level and degree of narrowing and may include exertional breathlessness, persistent or biphasic stridor, voice change, recurrent croup-like episodes, weak cough or difficulty clearing secretions.

Assess stability and the speed of progression. Stridor at rest, increased work of breathing, reduced air entry or fatigue needs urgent airway assessment. Stable suspected stenosis requires ENT review and direct visualisation; imaging may help define the level and extent. Definitive treatment can involve endoscopic or open airway procedures and is specialist-led. Do not attempt dilatation or instrumentation outside a trained, equipped setting.

14. Caustic ingestion and chemical injury

Accidental or intentional ingestion of corrosive household products can burn the lips, mouth, pharynx, larynx, oesophagus and stomach. Alkalis and acids may produce deep injury. Stridor, hoarseness, drooling, painful or difficult swallowing, vomiting, chest or abdominal pain, oral burns, breathing difficulty or reduced consciousness requires urgent emergency assessment. The mouth can look relatively normal even when deeper injury is present.

First response principles

• Protect rescuers from contact with the product; identify the container or label and the approximate time and amount, if known. Call emergency services or the local poison/toxicology service and arrange urgent transfer.
• Assess airway, breathing and circulation. Airway swelling can progress; early senior airway and ENT involvement is important when voice, breathing or secretion handling is abnormal.
• Do not induce vomiting, attempt to neutralise an acid with alkali or an alkali with acid, administer activated charcoal, or place a blind tube. These actions can worsen injury or delay definitive care.
• Do not force food, drink or home remedies. Nothing by mouth is safest when the person is drowsy, vomiting, drooling, in pain or unable to swallow. Follow poison-centre or receiving-clinician direction for any dilution advice.
• Inhalation or skin/eye exposure also requires prompt decontamination and medical assessment according to the product and local protocol. Do not delay hospital transfer to manage an exposure beyond your training.

15. Red flags and referral

• Stridor at rest, severe work of breathing, reduced air movement, cyanosis, exhaustion, altered consciousness, inability to speak or sudden choking.
• Drooling or inability to swallow saliva; rapidly progressive sore throat or neck swelling; suspected epiglottitis, deep-neck infection, Ludwig angina or sepsis.
• Suspected inhaled foreign body; sharp object or button battery in the oesophagus; complete food-bolus obstruction; or caustic ingestion.
• New hoarseness after neck trauma or surgery, hoarseness with stridor, coughing blood, a persistent neck lump, progressive dysphagia, unexplained weight loss or referred ear pain.
• Dehydration, inability to maintain oral intake, severe or recurrent infection, unilateral tonsillar enlargement, a pseudomembrane, immunosuppression or failure to improve as expected.
• Any patient whose airway, breathing, swallowing or general condition is worsening during observation or transfer.

16. Worked cases and self-check

Self-check questions

1. Name the three divisions of the pharynx and one important landmark in each.
2. What are the main functions of the larynx?
3. Outline the three phases of swallowing.
4. Give four features that suggest peritonsillar abscess.
5. Why should a distressed child with suspected epiglottitis not be forced to lie flat or undergo repeated throat examination?
6. How can an airway foreign body differ from an oesophageal foreign body?
7. Name four red flags in a patient with hoarseness.
8. List four actions to avoid after caustic ingestion.

Answers: 1. Nasopharynx (adenoid and auditory-tube openings), oropharynx (palatine tonsils), laryngopharynx (piriform fossae and oesophageal inlet). 2. Airway protection, controlled airflow, voice production and cough. 3. Oral preparatory/transport, pharyngeal and oesophageal. 4. Severe unilateral pain, trismus, muffled voice, drooling, palatal/tonsillar bulge and uvula deviation. 5. Distress and positioning can worsen obstruction and precipitate rapid deterioration. 6. Airway objects cause cough, choking, noisy breathing or impaired ventilation; oesophageal objects cause painful or blocked swallowing and drooling, though either can threaten breathing. 7. Stridor, dysphagia, blood, weight loss, neck lump, tobacco exposure, referred ear pain or persistent symptoms. 8. Do not induce emesis, neutralise, give activated charcoal or blindly pass a tube; do not force oral intake when swallowing is unsafe.

17. Key points to remember

• The pharynx is a shared passage for air and food; the larynx protects the lower airway and generates voice.
• Swallowing requires coordinated oral, pharyngeal and oesophageal phases; coughing with meals may indicate impaired airway protection.
• Most uncomplicated acute sore throats are managed according to the clinical picture and local guideline; do not prescribe antibiotics automatically.
• Stridor, drooling, inability to handle secretions, trismus with muffled voice, rapidly increasing neck swelling or a choking episode warrants urgent escalation.
• Keep a patient with possible severe upper-airway obstruction calm and in a position of comfort; do not force a throat examination.
• For caustic ingestion, do not induce vomiting, neutralise, give charcoal or delay urgent professional assessment.
• Persistent hoarseness, progressive dysphagia, a persistent neck lump, blood or weight loss needs timely investigation.

References and further reading

1. Uganda Ministry of Health. Uganda Clinical Guidelines 2023. Follow current national and facility protocols for antimicrobial treatment, referral and emergency care.
2. Royal Children’s Hospital Melbourne. Clinical Practice Guideline: Acute Upper Airway Obstruction. Paediatric emergency guidance on assessment, minimizing distress and escalation.
3. Royal Children’s Hospital Melbourne. Clinical Practice Guideline: Foreign Bodies Inhaled.
4. Royal Children’s Hospital Melbourne. Clinical Practice Guideline: Foreign Body Ingestion. International paediatric reference; local Ugandan pathways take precedence.
5. World Health Organization. Paediatric emergency triage, assessment and treatment: care of critically-ill children.
6. National Institute on Deafness and Other Communication Disorders. Taking Care of Your Voice.
7. NIDCD. Hoarseness.
8. MedlinePlus Medical Encyclopedia. Laryngitis.
9. US Agency for Toxic Substances and Disease Registry. Medical Management Guidelines for Sodium Hydroxide. Chemical exposure reference; urgent care should follow local poison and emergency advice.
10. National Health Service. Tonsillitis. Patient information; treatment decisions for Uganda should follow the Ministry of Health guideline.

Class notes: Coming soon.