The Larynx

Question 1

What is the larynx, where is it located and its functions?

Answer 1

Part of respiratory tract between oropharynx and trachea. Located between C3 and C6, below hyoid bone but will move when swallowing and is slight higher in newborns. It transports air, acts as a protective sphincter and is involved in phonation

Question 2

Name the laryngeal cartilages

Answer 2

• Epiglottis
• Thyroid
• Cricoid (only complete ring)
• Arytenoid
• Corniculate and cuneiform

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Question 3

where does the epiglottis project and where is it attached too?

Answer 3

• Projects upwards and backwards into the pharynx behind the posterior part of tongue.
• Attaches to thyroid cartilage via thyroepiglottic ligament.
• Attaches to hyoid bone by the hypoepiglottic ligament

Question 4

Describe the structure of the thyroid cartilage

Answer 4

• Left and right laminae,
• Superior and Inferior horns (superior attach to hyoid, inferior to cricoid)
• Superior thyroid notch
• Thyroid angle = laryngeal prominence (adams apple)
• Oblique line for muscle attachment.

Question 5

Describe the structure of the cricoid cartilage

Answer 5

• Articulates with arytenoid and thyroid

- Shape of a signet ring

Question 6

Describe structure of the arytenoid cartilages

Answer 6

• Articulates with sloping shoulders of cricoid lamina and superiorly with corniculate cartilage.
• Vocal process anteriorly for attachment of vocal ligament
• Muscular process posteriorly for attachment of the posterior and lateral crico-arytenoid muscles
• Depressions for vestibular ligament and attachment of vocalis muscle.

Question 7

Describe structure of thyro-htoid membrane

Answer 7

• Extends from thyroid laminae and superior horns to greater horns of hyoid.
• Thickened anteriorly and posteriorly as the median and lateral thyro-hyoid ligaments.
• Pierced by superior laryngeal vessels and nerve.

Question 8

What is the fibro-elastic membrane?

Answer 8

It is elastic connective tissue underneath the laryngeal muscous membrane and strtches between laryngeal cartilages and forms the fibro-elastic membranes.

Question 9

What is the fibro-elastic membrane separated by?

Answer 9

The laryngeal ventricle to form superiorly quadrangular membrane and inferiorly conus elasticus.

Question 10

Describe the positioning of the quadrangular membrane

Answer 10

It extends between lateral aspect of epiglottis, arytenoid and corniculate cartilages. The edges form the aryepiglottic fold and the vestibular ligament which when covered by mucous membrane forms vestibule fold.

Question 11

What is the clinical significance of the conus elasticus?

Answer 11

(cricovocal membrane)

- Blends anteriorly with the median cricothyroid ligament which is the site of emergency access to airway (Tracheotomy)

Question 12

Describe the functions of the vocal cord

Answer 12

It controls laryngeal diameter for:

• Speech
• Coughing/sneezing,
• Raising intra-abdominal pressure

Question 13

What widens or alters the tension of rima glottis?

Answer 13

the muscles within and adjacent to the vocal folds.

Question 14

What is the vestibule?

Answer 14

Between the laryngeal inlet and vestibular folds

Question 15

What is the laryngeal ventricle

Answer 15

Recess between vestibular and vocal folds which leads to the saccule which lubricates the vocal folds

Question 16

What is the infraglottic cavity?

Answer 16

It is the area between the vocal folds and trachea.

Question 17

What is the laryngeal inlet bound by?

Answer 17

Aryepiglottic folds

Question 18

What is the rima glottis?

Answer 18

Opening between vocal cords and muscular processes of arytenoid.

Question 19

Name the extrinsic muscles laryngeal muscles and their function

Answer 19

• Suprahyoid and infrahyoid muscle groups. They arrange position of larynx and facilitate closing of laryngeal inlet.

Question 20

What are the functions of the intrinsic laryngeal muscles

Answer 20

Adjust length or tension of vocal ligaments,

• Open or close rima glottis,
• control inner dimensions of vestibule,
• facilitate closing of laryngeal inlet.

Question 21

Name the elevators of the pharynx (extrinsic muscles) SPS

Answer 21

• Salpingopharyngeus
• Palatopharyngeus
• Stylopharyngeus

Question 22

Name the elevators of the larynx (extrinsic muscles)

Answer 22

• Stylohyoid
• Mylohyoid
• Geniohyoid
• Thyrohyoid
• Digastric

MaGa STD

Question 23

Name the depressors of the larynx

Answer 23

• Sternothyroid,
• Thyrohoid,
• Sternohyoid

Question 24

What are the muscles that close the laryngeal inlet?

Answer 24

• Salpingopharyngeus,
• Palatopharyngeus,
• Stylopharyngeus,
• Stylohyoid
• Ary-epiglottic muscle (Intrinsic muscle that acts as a purse string)
• Superior fibres of thyro-arytenoid muscle)
• (and elevation of larynx and pharynx by extrinsic muscles)

Question 25

What opens the laryngeal inlet?

Answer 25

Decent of laryngeal by elastic recoil and the hypoepiglottic ligament.

Question 26

What opens the rima glottis?

Answer 26

Posterior crico-arytenoid muscle

Question 27

What closes the rima glottis?

Answer 27

- Inferior fibres of thyro-arytenoid, - Lateral crico-arytenoid, - Transverse arytenoid muscle

Question 28

What causes lengthening of the vocal folds which in turn alters tension in vocal folds?

Answer 28

Thyroid cartilage may be rocked forwards and backwards at the cricothyroid joint - The crico-thyroid muscles changes in length - Vocalis muscle (changes in tension alter pitch of voice)

Question 29

Describe what occurs to the vocal folds in phonation

Answer 29

The vocal folds are adducted and air being forced through them makes a vibration.

Question 30

What occurs in effort closure?

Answer 30

Both vocal and vestibular folds are adducted so the airway is closed.

Question 31

Describe the process of swallowing

Answer 31

During swallowing the larynx elevated and there is the closure of the laryngeal inlet by the epiglottis. After, as the larynx descends the epiglottis springs back by hypoepiglottic ligament

Question 32

What is the arterial supply of larynx?

Answer 32

Superior laryngeal artery and the inferior laryngeal artery

Question 33

What is the venous drainage of the larynx and its clinical significance?

Answer 33

Superior laryngeal vein (drains to internal jugular vein) and the inferior laryngeal vein (drains to brachiocephalic). The inferior thyroid is at risk during tracheostomy

Question 34

Describe the lymphatic drainage of the larynx

Answer 34

Above the vocal cord - Superior deep cervical lymphnodes. Below vocal cord - Prelaryngeal, pretracheal, inferior deep cervical and supraclavicular lymph nodes.

Question 35

Describe the neural supply of the laryngeal cavity

Answer 35

Branches of the superior laryngeal nerve (SLN) (branch of vagus), the Internal branch of SLN (sensation of larynx down to just above vocal folds) and the external branch of SLN (supplies cricothyroid muscle). Then inferior laryngeal nerve (branch of vagus) and the reccurent laryngeal nerve (supplies intrinsic muscles of larynx except cricothyroid and sensation to vocal cords and below)