Anatomy of Pharynx and Hoarsness of Voice

Which cartilages of the larynx are single/unpaired versus paired, and what is the Adam's Apple gender difference?

Single (unpaired) cartilages: Thyroid, Cricoid, Epiglottis.
Paired cartilages: Arytenoids, Cuneiform, Corniculate.

The Laryngeal Prominence (Adam's Apple) is formed by the angle of the thyroid laminae: it is 90 degrees (right angle) in males, making it prominent, versus an obtuse 120 degrees in females, making it soft/not prominent. This angle also affects vocal cord stretch and voice pitch.

Describe the structure and unique features of the Cricoid Cartilage.

The Cricoid Cartilage ("Signet Ring") has an anterior narrow portion called the Arch and a posterior broad portion called the Lamina. It is unique as the only complete circular ring in the entire respiratory tract, and it contains facets for both the Cricoarytenoid and Cricothyroid joints.

What are the three membranes connecting laryngeal structures, and which one transmits an important nerve?

1) Thyrohyoid Membrane connects the hyoid bone to the thyroid cartilage and has an aperture transmitting the Internal Laryngeal Nerve;
2) Cricothyroid Membrane connects the cricoid to the thyroid cartilage;
3) Cricotracheal Membrane connects the cricoid to the first tracheal ring.

Describe the Arytenoid Cartilages, including their shape and the function of their two processes.

The Arytenoid Cartilages are triangular/pyramidal in shape and sit on the posterior cricoid lamina.
The Vocal Process serves as the attachment point for the vocal cords, while the Muscular Process serves as the attachment point for the intrinsic laryngeal muscles.

What are the key endoscopic landmarks seen when examining the internal larynx?

1) True Vocal Cords appear as white, V-shaped structures;
2) Anterior Commissure is where the two vocal cords meet anteriorly;
3) Posterior Commissure is the space between the arytenoid cartilages;
4) Aryepiglottic Folds are mucosal folds connecting the epiglottis to the arytenoids.

Classify the intrinsic laryngeal muscles by function, and identify the only extrinsic laryngeal muscle.

Adductors (closers): Lateral Cricoarytenoid, Transverse Arytenoid, Oblique Arytenoid.
Abductor (opener): Posterior Cricoarytenoid (PCA) - the only muscle that opens the airway.
Tensors (pitch control): Cricothyroid and Vocalis muscles.

The Cricothyroid is the only extrinsic laryngeal muscle (all others are intrinsic, located entirely inside the larynx).

What happens if the Posterior Cricoarytenoid (PCA) muscle is paralyzed bilaterally?

Bilateral paralysis of the PCA, the only abductor (opener) muscle of the larynx, results in Stridor, which is noisy, difficult breathing, because the airway cannot be opened.

Compare the Superior Laryngeal Nerve (SLN) and Recurrent Laryngeal Nerve (RLN) in terms of sensory and motor supply.

SLN Internal Branch is purely sensory, supplying the larynx above the vocal cords; SLN External Branch is purely motor, supplying only the Cricothyroid muscle.
The RLN provides motor supply to all laryngeal muscles except the Cricothyroid, and sensory supply to the larynx below the vocal cords.
Both nerves are branches of the Vagus nerve (CN X).

Explain the anatomical course difference between the Left and Right Recurrent Laryngeal Nerves and its clinical significance.

The Left RLN is longer and loops under the Arch of the Aorta, making it more prone to injury from chest tumors or aortic issues.
The Right RLN is shorter and loops under the Subclavian Artery.

What is Galen's Anastomosis, and what is its function? It is a connection between the sensory fibers of the SLN and RLN that provides sensory supply to the vocal cords themselves.

Describe the arterial supply and lymphatic drainage regions of the larynx.

Arterial supply comes from the External Carotid Artery via the Superior Laryngeal and Inferior Laryngeal arteries.
Lymphatic drainage: Supraglottis drains to Upper Deep Cervical nodes; Glottis drains to Paratracheal, Prelaryngeal, and Middle Deep Cervical nodes; Subglottis drains to Lower Deep Cervical nodes.

What are the three primary divisions of the pharynx, and what is the boundary/extension of the Nasopharynx?

The three primary divisions are: Nasopharynx (superior), Oropharynx (middle), and Hypopharynx/Laryngopharynx (inferior).
The Nasopharynx extends from the Skull Base down to the level of C2-C4 vertebrae and is a continuation of the posterior nasal cavity through the posterior choanae.

Describe the Eustachian Tube Orifice location and the clinical consequences of its obstruction.

The Eustachian Tube Orifice is located on the lateral wall of the nasopharynx and is responsible for equalizing ear pressure by connecting the nasopharynx to the middle ear.
Chronic obstruction causes middle ear effusion, while acute obstruction causes acute otitis media.

Describe the Nasopharyngeal Tonsils (Adenoids), including their growth pattern and complications of hyperplasia.

Adenoids are located between the roof and posterior wall of the nasopharynx, have no capsule, and contain superficial crypts.
Growth pattern: Hyperplasia occurs ages 2-6, stationary phase ages 6-8, regression ages 8-12 (may disappear after age 8).
Complications of hyperplasia include mouth breathing, "Adenoid face," dental issues (high arched palate), and Secretory Otitis Media.

What is the Fossa of Rosenmuller and why is it clinically important?

The Fossa of Rosenmuller is a depression located behind the Torus Tubarius((cushion of the auditory tube) is a rounded elevation of mucous membrane in the nasopharynx) in the nasopharynx. It is clinically significant as the primary site for Nasopharyngeal Carcinoma.

Define the boundaries of the Oropharynx and describe the Velopharyngeal sphincter mechanism.

The Oropharynx extends from the Soft Palate/Uvula superiorly to the tip of the Epiglottis inferiorly, bounded laterally by the tonsillar pillars and fossa/palatine tonsils, anteriorly by the tongue base/valeculae, and posteriorly by the posterior pharyngeal wall.
The Velopharyngeal sphincter closes via combined postero-superior movement of the soft palate, medial movement of lateral pharyngeal walls, and slight anterior movement of the posterior wall (Passavant's bridge), essential for deglutition and speech.

Describe the anatomy of the Palatine Tonsils, including crypts, capsule, and the pillars.

The Palatine Tonsils are lymphoid tissue on the lateral oropharyngeal wall, with the medial surface covered by mucous membrane containing 8-30 deep crypts (the largest being the Crypta Magna) and a distinct fibrous capsule. The Anterior Pillar is formed by the Palatoglossus muscle, and the Posterior Pillar by the Palatopharyngeus muscle.

What structures make up the Tonsillar Bed, and why is this clinically important during tonsillectomy?

The Tonsillar Bed consists of the Superior Constrictor Muscle, Glossopharyngeal Nerve, Facial Artery, and Buccopharyngeal Fascia. During tonsillectomy, an untrained surgeon may damage the nerve or facial artery if dissection goes beyond the tonsil's capsule.

List the five components of Waldeyer's Ring.

1) Nasopharyngeal Tonsil (Adenoids);
2) Tubal Tonsils (at the Torus Tubarius);
3) Palatine Tonsils;
4) Lingual Tonsil (lower pole of palatine tonsil extending to tongue base);
5) Lateral Pharyngeal Bands on the lateral pharyngeal walls.

Describe the anatomical subdivisions of the Hypopharynx and their clinical significance.

The Hypopharynx (behind the larynx) has three subdivisions:
1) Piriform Sinuses (paired recesses medial and lateral to aryepiglottic folds);
2) Post-cricoid Area (behind the cricoid cartilage);
3) Posterior Pharyngeal Wall.
These sites are frequent locations for Hypopharyngeal Carcinomas.

Describe the three pharyngeal constrictor muscles and their attachments.

Superior Constrictor attaches to the mandible and lies beside the palatine tonsil. Middle Constrictor attaches to the hyoid bone. Inferior Constrictor divides into two parts: Thyropharyngeus (attaches to thyroid cartilage) and Cricopharyngeus (attaches to cricoid cartilage).

Explain the motor and sensory nerve supply of the pharynx by region.

Motor supply is mainly via the pharyngeal plexus (formed by Glossopharyngeal nerve CN IX, Vagus nerve CN X, and cervical sympathetic trunk).
Sensory supply: Nasopharynx by trigeminal nerve (CN V); Oropharynx and tonsils by glossopharyngeal nerve (CN IX); Hypopharynx by vagus nerve (CN X).

Compare Direct and Indirect Laryngoscopy in terms of setting, doctor position, and orientation.

Direct Laryngoscopy is performed in the operating theatre under general anesthesia with the doctor standing behind the patient's head; orientation is natural (patient's right = doctor's right).

Indirect Laryngoscopy is performed in the outpatient clinic using a mirror or endoscope with the doctor sitting facing the patient; orientation is a mirror image (patient's right vocal cord appears on doctor's left), with the anterior commissure oriented toward the doctor.

Define Dysphonia and list its main organic causes including the components of Minimally Associated Pathology (MAP).

Dysphonia means hoarseness of voice, affecting pitch, loudness, and quality.
Causes are organic or psychogenic.
Organic causes include Minimally Associated Pathology (MAP: vocal cord nodule, polyp, granuloma, cyst, fibrosis, sulcus), plus inflammatory/infective, neoplastic, congenital, vocal cord paralysis/fixation, GERD, and age-related dysphonia.

Compare Vocal Cord Polyps and Vocal Nodules in terms of epidemiology, location, and first-line treatment.

Vocal Cord Polyps mainly affect males aged 30-50, often smokers or voice professionals, located on the anterior third of the free edge unilaterally, mobile during phonation; small polyps treated with smoking cessation, large ones with microlaryngosurgery.

Vocal Nodules mainly affect women, children, and singers, located at the junction of anterior and middle thirds bilaterally and symmetrically, immobile during phonation; first-line treatment is speech therapy, with surgery reserved for mature/refractory cases.

Describe Reinke's Edema, including its characteristic voice change and treatment approach.

Reinke's Edema is bilateral (62-85% of cases) sac-like swelling of the vocal folds occurring at ages 40-60, caused by smoking, GERD, hypothyroidism, or chronic voice abuse.
It causes persistent hoarseness with a distinctly low pitch due to increased weight of the vibrating vocal cord lowering fundamental frequency. Treatment is conservative (smoking cessation, vocal rest) if early, or surgical staged Decortication (one side, then the other 3-4 weeks later) for advanced cases.

Compare Contact Granulomas and Intubation Granulomas in terms of location and epidemiology.

Contact Granulomas occur more in males, appear as pale, pedunculated masses on the vocal process of the arytenoid cartilage, caused by repetitive crushing of thin mucosa against firm cartilage, treated with voice rest, GERD treatment, or surgery as a last resort.

Intubation Granulomas occur only in adults, more common in women (4:1 ratio) because the tube falls more posteriorly and mucosa is thinner, located near the posterior commissure, treated with excision if pedunculated but observation if sessile.

Describe Vocal Fold Cysts and Sulcus Vocalis, including their pathophysiology and characteristic symptoms.

Vocal Fold Cysts are sac-like fluid collections (mucus retention or epidermoid types) more common in females, size may vary with the menstrual cycle, treated conservatively or surgically if large.

Sulcus Vocalis is thinning or absence of the superficial lamina propria (congenital or from trauma/infection), causing hoarseness and vocal fatigue; men may be mistaken for women on the phone due to pitch changes, diagnosed via a linear depression on the true vocal fold.

Describe Acute Laryngotracheobronchitis (Croup), including etiology, epidemiology, and radiologic sign.

Croup is viral acute laryngotracheobronchitis occurring in winter, affecting children aged 1-3 years, presenting with fever, barking cough, and inspiratory stridor lasting no more than 7 days. The classic radiologic finding is the Steeple sign on X-ray, indicating a narrow infraglottic airway.

Describe Recurrent Respiratory Papillomatosis, including its cause and an important management contraindication.

Recurrent Respiratory Papillomatosis is the most common benign tumor of the larynx, caused by HPV types 6 and 11, affecting infants and children, with spontaneous involution typically at puberty.
Tracheostomy should be avoided as management, since it can seed the virus into the lower airway; treatments include laser, debrider, and topical agents like mitomycin.

Describe the key features of Diphtheria and Tuberculosis (TB) affecting the larynx.

Diphtheria is caused by Corynebacterium diphtheriae, primarily affects the nasopharynx, shows a classic gray dirty membrane, requires culture for diagnosis (treatment should not wait for culture results), and 10% develop cranial nerve palsies; prevented by the DPT vaccine.
Laryngeal TB is secondary to pulmonary TB (increasing with HIV association), classically affects the posterior larynx, and presents with hoarseness, odynophagia, cough, weight loss, night sweats, and hemoptysis.

Explain the role of GERD/Laryngopharyngeal Reflux (LPR) in causing hoarseness, including epidemiology and examination signs.

GERD/LPR is a major cause of hoarseness and causes most Minimally Associated Pathology (MAP) lesions; 90% of children and infants have GERD.
Symptoms include cough, postnasal drip, dysphagia, globus sensation, and throat clearing. Laryngeal examination shows erythema, edema, cobblestoning, interarytenoid predilection, ulcers, and granulations.

Describe Glottic Tumors, including their histology, presentation, and why they have a high cure rate.

Glottic Tumors are mostly squamous cell carcinoma,
arising from the true vocal cord, anterior/posterior commissures, or vocal processes of the arytenoid cartilage.

They cause hoarseness early even when small, leading to early detection;

they also have a high cure rate partly due to the lack of lymphatics in the true vocal cord.

Treatment is radiotherapy or surgical excision depending on stage.

Differentiate between Vocal Fold Fixation and Vocal Fold Paralysis as causes of vocal cord immobility.

Vocal Fold Fixation is a mechanical restriction, most commonly post-surgical, also caused by irradiation, intubation (arytenoid dislocation), glottic cancer, trauma, or systemic diseases like gout, sarcoidosis, TB, and rheumatoid arthritis affecting the cricoarytenoid joint.

Vocal Fold Paralysis is a neurological loss of mobility due to nerve injury, which can be unilateral or bilateral.

List the causes of Unilateral Vocal Fold Paralysis in order of frequency, and the leading causes of Bilateral Vocal Fold Paralysis.

Unilateral paralysis malignant causes in order:
1st Bronchogenic carcinoma (affecting Left RLN), 2nd Thyroid cancer, 3rd Esophageal cancer, 4th Skull base tumors; surgical causes include thyroidectomy and neck dissection.
Bilateral paralysis causes by frequency: Iatrogenic (80%), Malignancy (10%), Neurologic (5%), plus intubation and metabolic disorders.

How can a clinician quickly differentiate hysterical/conversion dysphonia from organic vocal cord paralysis?

Ask the patient to cough. If the cough sounds normal and explosive, the true vocal cords are structurally intact and capable of full adduction, indicating the dysphonia is psychogenic (conversion) rather than due to true organic paralysis.

What are the three lines of non-surgical treatment for hoarseness, and what are the surgical options?

Non-surgical treatment includes:
1) Voice hygiene advice (e.g., quit smoking);
2) Treat laryngopharyngeal reflux if suspected (antacids, H2 blockers, prokinetics, sucralfate, or fundoplication);
3) Voice therapy to eliminate harmful vocal behaviors.

Surgical treatments include Microlaryngosurgery (MLS) using micro-instruments or CO2 laser, Type 1 Thyroplasty to medialize a paralyzed cord, and Vocal Fold Injection using materials like fat, Teflon, or hyaluronic acid

Mention the main arterial supply of palatine tonsil.

Tonsillar artery from Facial artery