Larynx

Intrinsic muscles of the larynx

- Posterior cricoarytenoid - inter (transverse and oblique) arytenoid - lateral cricoarytenoid - cricothyroid - thyroarytenoid - vocalis

The larynx spans from C__ to C__

3 to 6

The mucosa of the upper larynx is innervated by the a) internal laryngeal nerve which is the afferent limb of the cough reflex. b) external laryngeal nerve which is the afferent limb of the gag reflex. c) internal laryngeal nerve which is the afferent limb of the gag reflex. d) external laryngeal nerve which is the afferent limb of the cough reflex.

A

The mucosa of the upper larynx is innervated by the a) internal laryngeal nerve which is the afferent limb of the cough reflex. b) external laryngeal nerve which is the afferent limb of the gag reflex. c) internal laryngeal nerve which is the afferent limb of the gag reflex. d) external laryngeal nerve which is the afferent limb of the cough reflex.

A The internal branch of the superior laryngeal nerve is sensory to the mucosa of the larynx whereas its external branch is motor to the cricothyroid muscle. The cough reflex occurs due to irritation of the laryngeal mucosa whereas the gag reflex occurs in response to foreign bodies in the oropharynx

Label a-c

A - Cricoid cartilage B - arytenoid C - thyroid

Label A-E

A - Superior thyroid notch B - Laryngeal prominence C - Inferior thyroid notch D - Superior horn E - inferior horn

Label A-D

A - corniculate cartilage B - arytenoid cartilage C - thyroid cartilage D - cricothyroid cartilage

Sensory innervation of larynx above the vocal cords and below the vocal cords by

Above = superior laryngeal nerve Below = recurrent laryngeal nerve

Laryngeal prominence is also known as

Adam's apple (thyroid cartilage)

Laryngeal Inlet margins

Anterior = epiglottis Laterally - ariepiglottic folds Posteriorly = interarytenoid tissues

Paired laryngeal cartilages

Arytenoid Cuneiform Corniculate

Vocal folds are two folds of mucous membrane stretched across the larynx from the ___ cartilages posteriorly to the ___ cartilage anteriorly

Arytenoid Thyroid

Laryngeal oedema is usually confined to the larynx above the vocal folds because a) there are numerous mucous glands in the vestibular folds. b) the mucosa covering the vocal folds is tightly attached to underlying tissues. c) fluid will drain rapidly into the thorax below the vocal folds. d) the mucosa above the vocal folds is more vascular than that below the vocal folds.

B

Laryngoscopic examination of the vocal folds after suspected recurrent laryngeal nerve damage usually shows that the vocal fold on the injured side is tensed and in an intermediate position between adduction and abduction. This is because a) cricothyroid muscle is still functional but the interarytenoid muscles are fully active. b) cricothyroid muscle is still functional but the interarytenoids are weak. c) cricothyroid muscle is paralyzed but the interarytenoids are fully active. d) cricothyroid muscle is paralyzed but the interarytenoids are weak.

B

When an emergency opening into the airway is required, the cricothyroid membrane should be pierced immediately a) superior to the thyroid cartilage. b) inferior to the thyroid cartilage. c) inferior to the cricoid cartilage. d) superior to the thyroid isthmus.

B

Laryngeal oedema is usually confined to the larynx above the vocal folds because a) there are numerous mucous glands in the vestibular folds. b) the mucosa covering the vocal folds is tightly attached to underlying tissues. c) fluid will drain rapidly into the thorax below the vocal folds. d) the mucosa above the vocal folds is more vascular than that below the vocal folds.

B Oedema usually occurs between the mucosal layer and underlying connective tissue and gravitates down the larynx. The stratified squamous epithelium forming the superficial surface of the mucosa covering the vocal folds is tightly bound down to the connective tissue covering the vocalis muscle and prevents flow of fluid below that point. There are mucous glands in the vestibular folds and there is no apparent difference in vascular density in different parts of the larynx.

When an emergency opening into the airway is required, the cricothyroid membrane should be pierced immediately a) superior to the thyroid cartilage. b) inferior to the thyroid cartilage. c) inferior to the cricoid cartilage. d) superior to the thyroid isthmus.

B The cricothyroid membrane is in the anterior midline of the neck between the inferior border of the thyroid cartilage and the cricoid cartilage. It is palpable between the two cartilages especially if the neck is extended.

Laryngoscopic examination of the vocal folds after suspected recurrent laryngeal nerve damage usually shows that the vocal fold on the injured side is tensed and in an intermediate position between adduction and abduction. This is because a) cricothyroid muscle is still functional but the interarytenoid muscles are fully active. b) cricothyroid muscle is still functional but the interarytenoids are weak. c) cricothyroid muscle is paralyzed but the interarytenoids are fully active. d) cricothyroid muscle is paralyzed but the interarytenoids are weak.

B The cricothyroid muscle is supplied by the external branch of the superior laryngeal nerve therefore is not affected by recurrent laryngeal nerve damage; it tenses the vocal fold and its action will be unopposed because vocalis is paralyzed. The interarytenoids are unusual in that they cross the midline and receive a bilateral nerve supply from both recurrent laryngeal nerves; if one nerve is injured the muscle will still receive some nerve supply but its action is weaker resulting in the intermediate position. Again its action is unopposed because the posterior cricothyroid muscles are paralyzed.

The auditory tube a) connects the inner ear and nasopharynx. b) is derived from the second pharyngeal pouch. c) is opened by the action of levator veli palatini. d) is closed by the action of tensor veli palatini.

C

The muscles of the soft palate are innervated by branches of the a) trigeminal and glossopharyngeal nerves. b) facial and glossopharyngeal nerves. c) trigeminal and vagus nerves. d) facial and vagus nerves.

C

Tonsillar tissue is commonly found a) on the posterior wall of the oropharynx. b) under the mucosa of the ventral surface of the tongue. c) between the palatoglossal and palatopharyngeal folds. d) at all three sites.

C

What level are the greater horns at?

C3/c4

The trachea begins at the lower border of the ___ cartilage (C6)

Cricoid

The intrinsic muscles of the larynx are innervated by the recurrent laryngeal nerve, except for ___ which is innervated by the external laryngeal nerve

Cricothyroid muscle

The respiratory tract is crossed by the isthmus of the thyroid gland at the level of the a) thyroid cartilage. b) cricothyroid membrane. c) cricoid cartilage. d) tracheal rings.

D

During puberty there is ___ of the larynx and ___ of the vocal folds

Expansion Elongation

The larynx is narrowest at the

Glottis

Identify coloured parts of the larynx

Green - epiglottis Red - thyroid cartilage Blue - arytenoid cartilage Yellow - cricoid cartilage Purple - corniculate cartilage

Subglottis spans

Inferior border of glottis to the inferior border of cricoid cartilage

The superior laryngeal vein drains into the ___ ___ vein via the superior thyroid

Internal jugular vein

During phonation the arytenoid are medially rotated and adducted by contraction of the

Lateral cricoarytenoid muscles

aryepiglottic folds form which margin of the laryngeal inlet

Lateral margin

The inferior laryngeal vein drains to the

Left brachiocephalic vein via the inferior thyroid vein

Intrinsic muscles of the larynx control

Length and tensions of vocal cords Size and shape of the rims glottidis

The size of rims glottidis is altered by

Muscles of phonation

The interior surface of larynx is lined by ___ ___ ___ ___. What is the exception?

Pseudostratified ciliated columnar epithelium. Except true vocal cords - lined by stratified squamous epithelium

Motor innervation of the intrinsic muscles of the larynx except cricothyroid muscle

Recurrent laryngeal nerve

Low pitched sounds are produced when the folds are

Relaxed (long and thin)

The opening between the vocal cords is known as

Roma glottidis

The trachea ends in the ___ ___ ___ ___ by dividing into the right and left bronchi

Second right costal cartilage

Recurrent laryngeal nerve provides sensory innervation to ___ and motor innervate in to ___

Sensory = infraglottis Motor = intrinsic muscles of larynx

Superior laryngeal nerve provides sensory innervation to ___ and motor innervation to ___

Sensory = supraglottis Motor - Cricothyroid muscle

Vocal folds are lined with

Stratified squamous epithelium

BS to larynx

Superior laryngeal artery (external carotid) Inferior laryngeal artery (thyrocervical trunk) Venous drainage via superior and inferior laryngeal veins

Motor of the cricothyroid muscle

Superior laryngeal nerve

High pitched sounds are when the folds are

Taught (fat and short)

The pitch of a sound reflects what feature of the vocal folds

Tension and length

Supraglottis spans

The inferior surface of the epiglottis to the vestibular folds (Faldo vocal cords)

Unpaired laryngeal cartilages

Thyroid cartilage Cricoid cartilage Epiglottis

Beneath the cricoid cartilage lies the

Trachea

True or false: The left recurrent laryngeal nerve passes under the aortic arch and up to innervate the larynx

True

The larynx receives both motor and sensory innervation via branches of the

Vagus nerve

What sphincter regulates nasality of speech

Velopharyngeal sphincter

What folds lie above and lateral to the vocal folds

Vestibular folds

The glottis contains

Vocal cords and 1cm below them.

The vocal folds contain a muscle known as the

Vocalis muscle

Suprahyoid muscles

digastric, stylohyoid, mylohyoid, geniohyoid

laryngeal inlet is

opening that connects the pharynx and larynx

infra hyoid muscles

sternohyoid, omohyoid, sternothyroid, thyrohyoid

Function of greater horns (greater cornua)

support larynx and attach muscles of the tongue

Extrinsic muscles of the larynx move the larynx. these include

suprahyoid and infrahyoid muscles