Ear and larynx

Question 1

What are the internal features of the larynx?

Answer 1

Laryngeal skeleton includes:
Single cartilages: Thyroid, cricoid, and epiglottis.
Paired cartilages: Arytenoid, corniculate, and cuneiform.
Spaces: Rima vestibuli (between vestibular folds) and rima glottidis (between vocal folds).
Lining: Respiratory epithelium, except for vocal folds (non-keratinized squamous epithelium).

Question 2

What are the major movements in the larynx and their muscles?

Answer 2

Movements: Abduction of vocal folds: Posterior cricoarytenoid muscle. Adduction: Lateral cricoarytenoid, transverse, and oblique arytenoid muscles. Tension adjustment: Cricothyroid muscle (raises pitch). Innervation: External laryngeal nerve (motor to cricothyroid). Recurrent laryngeal nerve (all other intrinsic muscles).

Question 3

What are the effects of laryngeal nerve injury?

Answer 3

External laryngeal nerve: Weak voice or inability to adjust pitch. Recurrent laryngeal nerve: Hoarseness or loss of voice; bilateral injury may cause airway obstruction.

Question 4

What are the major relations of the walls of the middle ear?

Answer 4

Roof: Petrous temporal bone.
Floor: Jugular vein.
Medial wall: Promontory, oval and round windows.
Anterior wall: Eustachian tube, internal carotid artery.
Posterior wall: Facial nerve, mastoid air cells.

Question 5

What spaces communicate with the middle ear?

Answer 5

Eustachian tube connects to the nasopharynx: Equalizes pressure. Aditus to mastoid antrum connects to mastoid air cells: Potential pathway for infection.

Question 6

What is the clinical significance of middle ear infections?

Answer 6

Can spread to: Brain (via petrous temporal bone). Mastoid air cells (mastoiditis). Nasopharynx (via Eustachian tube).

Question 7

What is the morphology and innervation of the external acoustic meatus?

Answer 7

Morphology: Lateral 2/3 elastic cartilage, medial 1/3 bony. Sensory innervation: Auriculotemporal nerve (V3). Auricular branch of vagus nerve (X).

Question 8

What are the features of the tympanic membrane as seen through an otoscope?

Answer 8

Shape: Concave with a central umbo. Visible landmarks: Handle of malleus, light reflex, and pars flaccida.

Question 9

How does the ear convert sound vibrations to nerve impulses?

Answer 9

External ear collects sound. Middle ear amplifies sound via ossicles (malleus, incus, stapes). Inner ear (cochlea): Hair cells in the organ of Corti convert mechanical vibrations into nerve signals.

Question 10

How does epithelium change across the pharynx and larynx?

Answer 10

Nasopharynx: Respiratory epithelium. Oropharynx and laryngopharynx: Non-keratinized squamous epithelium. Larynx: Respiratory epithelium, except vocal folds (non-keratinized squamous epithelium).

Question 11

What are the movements of the vocal cords during phonation?

Answer 11

Adducted by lateral cricoarytenoid and arytenoid muscles. Controlled tension via cricothyroid muscle.

Question 12

What features can be observed in the larynx during endoscopy?

Answer 12

Epiglottis, vestibular folds, vocal folds, valleculae, pyriform fossae.

Question 13

What internal features of the nasopharynx can be observed during endoscopy?

Answer 13

Torus tubarius (surrounds the opening of the Eustachian tube). Pharyngeal tonsils (adenoids). Pharyngeal recess.

Question 14

What are the important relations and lymphatic drainage of the nasopharynx?

Answer 14

Relations: Superior: Base of skull.
Posterior: Cervical vertebrae.
Lateral: Eustachian tube and surrounding structures.
Lymphatic drainage: Retropharyngeal lymph nodes, deep cervical lymph nodes.

Question 15

What are the boundaries and innervation of the palatine tonsils?

Answer 15

Boundaries:
Superior: Soft palate.
Inferior: Tongue.
Lateral: Tonsillar fossa bounded by palatoglossal and palatopharyngeal arches.
Innervation: Glossopharyngeal nerve (CN IX).

Question 16

What are the three phases of deglutition?

Answer 16

Oral phase:
Voluntary; bolus formation and propulsion by the tongue.
Muscles: Intrinsic/extrinsic tongue muscles.
Nerve: Hypoglossal (CN XII).

Pharyngeal phase:
Involuntary; bolus moves through pharynx.
Muscles: Pharyngeal constrictors.
Nerves: Vagus (CN X) and glossopharyngeal (CN IX).

Esophageal phase:
Involuntary; bolus passes into the esophagus.
Muscles: Esophageal smooth muscles.
Nerve: Vagus (CN X).

Question 17

What is the clinical importance of the recurrent laryngeal nerve?

Answer 17

Supplies motor innervation to all intrinsic laryngeal muscles (except cricothyroid). Damage leads to: Unilateral: Hoarseness and weak voice. Bilateral: Respiratory obstruction due to vocal cord paralysis.

Question 18

What is the significance of the superior laryngeal nerve?

Answer 18

External branch: Motor to cricothyroid (affects pitch). Internal branch: Sensory to laryngeal mucosa above the vocal cords. Injury during thyroid surgery may cause voice weakness.

Question 19

What structures of the inner ear are involved in hearing?

Answer 19

Cochlea (spiral organ of Corti): Converts sound vibrations to nerve impulses. Nerve: Cochlear division of the vestibulocochlear nerve (CN VIII).

Question 20

What is the clinical relevance of the tympanic membrane?

Answer 20

Boundary between external and middle ear. Damage (e.g., perforation) can impair hearing and expose the middle ear to infection.

Question 21

How is the innervation of the pharynx and larynx derived embryologically?

Answer 21

Derived from pharyngeal arches: 1st arch: Mandibular nerve (V3). 2nd arch: Facial nerve (CN VII). 3rd arch: Glossopharyngeal nerve (CN IX). 4th and 6th arches: Vagus nerve (CN X).

Question 22

What are the valleculae and pyriform fossae?

Answer 22

Valleculae: Depressions between the base of the tongue and epiglottis, serving as ‘spit traps.’ Pyriform fossae: Recesses in the laryngopharynx lateral to the laryngeal inlet, common sites for foreign body lodging.

Question 23

What are the functions of the vocal folds?

Answer 23

Phonation (sound production). Regulating airflow through the glottis. Preventing food aspiration by closing during swallowing.

Question 24

How does the recurrent laryngeal nerve relate to surgical anatomy?

Answer 24

Left RLN: Loops under the aortic arch. Right RLN: Loops under the right subclavian artery. Vulnerable to damage during thyroid, cardiac, or neck surgeries.

Question 25

What are the dual roles of the internal laryngeal nerve?

Answer 25

Provides sensory innervation above the vocal folds. Facilitates reflex closure of the glottis to protect the airway.

Question 26

What is the functional role of the Eustachian tube?

Answer 26

Equalizes pressure between the middle ear and nasopharynx. Drains mucus from the middle ear into the nasopharynx. Opened by the tensor veli palatini and levator veli palatini muscles during swallowing or yawning.

Question 27

What are the clinical implications of the mastoid antrum?

Answer 27

Communicates with the mastoid air cells posteriorly and the middle ear anteriorly. Infections can spread to the mastoid cells (mastoiditis) or the brain (via temporal bone erosion).

Question 28

What can be observed during endoscopic examination of the larynx?

Answer 28

Structures: Epiglottis, vestibular folds, vocal folds, aryepiglottic folds, and interarytenoid notch. Movements: Abduction and adduction of vocal folds, epiglottic closure during swallowing.

Question 29

What are the changes in vocal cord movement during phonation and breathing?

Answer 29

Phonation: Vocal cords adduct and vibrate. Breathing: Quiet breathing: Vocal cords are partially abducted. Forced inspiration: Vocal cords fully abduct via posterior cricoarytenoid muscles.

Question 30

What precautions should be taken during tympanic membrane examination?

Answer 30

Pull the auricle backward and upward to straighten the canal. Identify the umbo, handle of malleus, and cone of light for landmarks.

Question 31

What are the key muscles involved in swallowing?

Answer 31

Oral phase: Intrinsic/extrinsic tongue muscles (hypoglossal nerve). Pharyngeal phase: Pharyngeal constrictors (vagus and glossopharyngeal nerves). Esophageal phase: Esophageal muscles (vagus nerve).

Question 32

What is keratinized squamous epithelium?

Answer 32

Thick for mechanical resistance to abrasion during swallowing or vocal fold movement.

Question 33

What structures can be identified during endoscopic examination of the nasal cavity?

Answer 33

Nasal septum, turbinates, and choanae.

Question 34

What structures can be identified during endoscopic examination of the pharynx?

Answer 34

Nasopharynx, oropharynx, and laryngopharynx, with key landmarks like the epiglottis and aryepiglottic folds.

Question 35

What should be appreciated during endoscopic examination of the larynx?

Answer 35

Movements of vocal cords during phonation and respiration, and borders of the laryngeal inlet.

Question 36

What features should be identified in the larynx during examination?

Answer 36

Cartilages: Thyroid, cricoid, arytenoid, corniculate, and cuneiform.

Spaces: Rima vestibuli and rima glottidis. Muscles: Cricothyroid, posterior and lateral cricoarytenoids, interarytenoids.

Question 37

What is the role of the cricothyroid muscle?

Answer 37

Adjusts tension of the vocal cords by tilting the thyroid cartilage downward and forward, raising pitch during phonation.

Question 38

What is the clinical importance of the cricothyroid membrane?

Answer 38

Site for emergency cricothyrotomy to establish an airway in upper airway obstruction.

Question 39

What is the role of the epiglottis during swallowing?

Answer 39

The epiglottis folds backward to close the laryngeal inlet, preventing food and liquids from entering the airway.

Question 40

What are the clinical implications of vocal cord paralysis?

Answer 40

Unilateral paralysis: Hoarseness, weak voice, aspiration risk.
Bilateral paralysis: Airway obstruction due to inability to abduct the vocal cords.

Question 41

How does the ear convert sound vibrations into nerve impulses?

Answer 41

External ear: Collects sound waves.
Middle ear: Amplifies vibrations via ossicles (malleus, incus, stapes).
Inner ear: Cochlear hair cells in the organ of Corti transform vibrations into electrical signals transmitted by the cochlear nerve.

Question 42

What are the components of the vestibular system, and their roles?

Answer 42

Utricle and saccule: Detect linear acceleration.

Semicircular canals: Detect rotational movements.

Vestibular nerve: Transmits signals for balance and posture.

Question 43

What are the communications of the middle ear cavity?

Answer 43

Anteriorly: Eustachian tube (connects to nasopharynx).
Posteriorly: Aditus to mastoid antrum (leads to mastoid air cells).

Question 44

Why is the middle ear clinically significant in otitis media?

Answer 44

Infections can spread to the:
Nasopharynx via the Eustachian tube.
Mastoid air cells (mastoiditis).
Cranial cavity causing meningitis or brain abscess.

Question 45

What are the main features of the tympanic membrane as seen through an otoscope?

Answer 45

Appearance: Pearly gray, translucent.
Landmarks: Handle of malleus, umbo, cone of light (anteroinferior quadrant).

Question 46

How is the epithelium adapted to functional requirements?

Answer 46

Respiratory epithelium: Thin and ciliated for mucus clearance.
Non-keratinized squamous epithelium: Thick for mechanical resistance to abrasion during swallowing or vocal fold movement.

Question 47

What structures can be identified during endoscopic examination of the nasal cavity and pharynx?

Answer 47

Nasal cavity: Nasal septum, turbinates, and choanae.
Pharynx: Nasopharynx, oropharynx, and laryngopharynx, with key landmarks like the epiglottis and aryepiglottic folds.