HUBS1107 Lecture Notes - Lecture 8: Recurrent Laryngeal Nerve, Superior Laryngeal Nerve, Thyroid Cartilage
26 Oct 2018
School
Department
Course
Professor
Identify the location of the larynx
•
Locate and correctly name the cartilages that make up the larynx
•
Describe the main movements of the vocal cords and which muscles produce these main
movements
•
Describe the main innervation of the larynx and locate the jugular foramen on a skull
•
View and describe the different paths of the right and left recurrent laryngeal nerves
•
Lecture objectives:
Extends from the root of tongue (close to hyoid bone) to trachea
→
Lies between the level of the third to six cervical vertebrae in the neck region
→
Adam's apple in a male is the prominence of the larynx
-
Larger in males vs females, especially AP diameter (36mm vs. 26mm)
→
Hollow structure made up of a framework formed by cartilages, ligaments and
membranes that are attached to them
→
Mucous membrane reflects over these cartilages and ligaments forming vestibular and
vocal folds - mucosal lining helps in making structures such as vocal folds, chambers above
and below the larynx (vestibule)
→
Vestibule
•
Ventricle
•
Infraglottic cavity
•
These folds form three parts of the larynx:
→
Considered a shield as it is protective
•
Epiglottis is attached to inside of thyroid cartilage by ligamentous attachments
•
Thyroid cartilage = U shaped, forms anterior and lateral walls
→
Laryngeal prominence of males are considerably more prominent than females
•
Anterior prominence = laryngeal prominence (Adam's apple)
→
Superior surface has ligamentous attachments to the hyoid bone
→
Inferiorly articulates with the cricoid cartilage in a moveable joint - synovial joint as it is a
cartilage moving to a certain extent on a cartilage below it to help change diameter in that
region
→
Larynx - anatomy
Cricoid - ring (protects the larynx from a posterior aspect)
→
Thyroid - shield/visor (protects the structures of larynx)
→
Arytenoid sits on top of cricoid cartilage and muscles attaches to those three
processes to allow arytenoids to slide, turn and twist
-
Odd shaped of arytenoids means muscles can attach to those three points and
allows movements
-
Movements of arytenoid contributes to movements of the vocal folds
-
Arytenoid - three processes, ladle shaped
→
Corniculate - tips on arytenoids
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Cuneiform - structure
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If move thyroid cartilage up and forward, it causes the epiglottis to fold
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Epiglottis - leaf like shaped
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Skeleton of the larynx
Cartilage and ligament arrangement
Note: need to be able to name main cartilages
→
There are muscle attachments from the arytenoid forward to
→
the thyroid cartilage - help in making vocal folds and vocal ligaments
Sits below thyroid cartilage
→
Expanded posteriorly (back), but a more thinner ring at the front, to provide support in
absence of the thyroid
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With the thyroid protect the glottis and the entrance to the trachea
→
Has muscles coming off it to the thyroid to help move the chamber
-
Provides attachment for laryngeal muscles
→
Superior surface of cricoid articulates with small paired arytenoid cartilages
→
Cricoid cartilage
The Larynx
Saturday, 2 September 2017
3:55 PM
HUBS1107 Page 10.1
Thyroid cartilage articulating with the Cricoid cartilage
3 pairs of small cartilages
→
Arytenoid (ladle shaped) articulate with superior border of cricoid cartilage
→
Corniculate (horn shaped) articulate with arytenoid cartilages (form the tip of the
arytenoids)
→
Together these two pairs of cartilages function to open and close glottis and produce
sounds
→
Cuneiform (wedge shaped) lie within aryepiglottic folds (mucosal folds) giving
form/structure to the folds
→
Arytenoid, Corniculate and Cuneiform Cartilages
Cricoid cartilage
Phonation function obvious in many vertebrate species
→
Larynx highly evolved/specialized in man for phonation
→
It is part of our respiratory system with two things going on; a sphincter at lower
part of respiratory system (protector of what goes in and out of respiratory system)
that has been altered to make speech sounds
-
Phonation defined as the production of sounds via movements of vocal folds
→
With the opening and closing of air chamber, we can make sounds through
the vibration and increase those resonance of vibration through the chambers
above
-
Movements of vocal folds and changes in their tension alter properties of sounds
made by air moving through rima glottidis (vocal folds)
1.
Changes in shape of resonant chambers (i.e., thyroid area, mouth, etc) rostral to
vocal cords
2.
Speech is intricate. We need to produce speech in the larynx with air travelling
through, need to vibrate the chambers above the vocal cords and interrupt
them using tongue, mouth, palate, teeth and lips
-
Plus movements of tongue, mouth, palate, teeth, and lips shape these sounds into
intelligible speech
3.
Generally:
→
Larynx
Cricoid and thyroid cartilage has a sort-of
synovial joint that is movable
•
The movement allows the thyroid
cartilage to move forwards and backwards
on the cricoid
•
Note: For lab, make sure can find thyroid, cricoid
and arytenoid cartilages !!!
Arytenoid and corniculate
Cartilages
surrounding
HUBS1107 Page 10.2
Document Summary
Locate and correctly name the cartilages that make up the larynx. Describe the main movements of the vocal cords and which muscles produce these main movements. Describe the main innervation of the larynx and locate the jugular foramen on a skull. View and describe the different paths of the right and left recurrent laryngeal nerves. Extends from the root of tongue (close to hyoid bone) to trachea. Lies between the level of the third to six cervical vertebrae in the neck region. Larger in males vs females, especially ap diameter (36mm vs. 26mm) Adam"s apple in a male is the prominence of the larynx. Hollow structure made up of a framework formed by cartilages, ligaments and membranes that are attached to them. Mucous membrane reflects over these cartilages and ligaments forming vestibular and vocal folds - mucosal lining helps in making structures such as vocal folds, chambers above and below the larynx (vestibule)
