The Larynx 1 Flashcards
What is the larynx?
A valve that protects the entrance to the airway or tracheobronchial tree.
Aside from its protective role, what else is the larynx responsible for?
It is involved in the production of speech sounds and in phonation in humans.
What happens if the protective role of the larynx is ineffective?
Laryngeal incompetence –> fluid and food is regurgitated into the trachea.
What is the larynx composed off?
4 major cartilages that are united by mobile synovial joints.
Aside from the mobile synovial joints, what else fills the spaces between the 4 major cartilages?
Ligaments and membranes.
Describe the walls of the larynx.
The larynx has outer and inner walls.
These look like 2 flower pots, once placed inside the other.
Where do the outer and inner walls of the larynx arise from?
They arise from a circular base which is called the cricoid ring.
Which structures form the outer wall of the larynx?
- thyroid cartilage
- thyrohyoid cartilage
- cricoid cartilage
- cricothyroid cartilage
Which is the largest cartilage of the larynx?
The thyriod cartilage is the largest cartilge.
What does the thyroid cartilage consists of?
Consists of 2 laminae that meet at the midline.
What does the thyroid cartilage project as?
Projects as a laryngeal prominence and this can be seen and palpated in the midline of the neck.
How is the angle between the 2 thyroid laminae different in men and women?
In men, the angle is more acute at puberty.
Where can the superior thyroid notch be palpated?
It can be palpated between the 2 laminae, above the laryngeal prominence.
Describe the posterior border of each thyroid cartilage?
It is extended above and below as slender superior and inferior horns or cornua.
What is the shape of the cricoid cartilage?
It is the shape of a signet ring. The narrow part of the ring lies in front and the thick part of the ring behind.
Where can the front of the cricoid be palpated?
It can be palpated in the neck below the thyroid cartilage.
What does the inferior cornu of each thyroid lamina articulate with?
It articulates with a facet on the side of the cricoid at a synovial articulation.
What is the outer wall of the larynx completed by?
It is completed by several membranes.
What does the upper border of each lamina of the thyroid cartilage give attachment to?
It gives attachment to the thyrohyoid membrane.
What does the other end of the thyroid cartilage give attachment to?
It extends upwards to give attachment to the inner border of the hyoid bone in the floor of the mouth.
How is the lower border of the thyroid cartilage attached to the cricoid?
It is attached in the midline by a strong cricothyroid ligament.
Below, how is the lower border of the cricoid attached to the trachea?
It is attached to the uppermost ring of the trachea via the cricotracheal ligaments.
What is the inner wall of the larynx composed off?
- membrane
- muscles
- arytenoid cartilages posteriorly
- epiglottis above
How is the structure of the inner wall best appreciated?
It we remove 1 thyroid lamina.
What is the epiglottis shaped like?
It is shaped like a leaf.
How is the epiglottis attached to the inner surface of the angle of the thyroid laminae?
It is attached by a ligament to the inner surface of the angle of the thyroid laminae.
What does the epiglottis project upwards behind?
It projects upwards behind the:
- thyrohyoid membrane
- hyoid bone
- tongue
Where do paired arytenoid cartilages sit?
Sit on the upper border of the lamina of the cricoid.
What is the shape of each arytenoid cartilage?
They are each pyramidal in shape.
What is the joint between the arytenoid and the cricoid?
This is synovial.
What is the inner wall of the larynx completed by?
It is completed by a membrane which extends from the sides of the epiglottis above to the arytenoid cartilage behind and down to the lower part of the thyroid cartilage below.
What is the quadrangular membrane?
This is the part of the fibroelastic membrane that runs between the side of the epiglottis and arytenoid.
What does the quadrangular membrane end?
It ends below at a sharp free border that runs between the arytenoid cartilage behind and the thyroid lamina in front.
What is the sharp free border of the quadrangular membrane called?
This is called the vestibular ligament.
Describe the upper part of the quadrangular membrane?
This is less developed and is replaced by muscle fibres.
What is there below the vestibular ligament?
There is a slit like gap.
What is present beneath the slit that is below the vestibular ligament?
We have the conus elasticus or the cricovocal membrane.
Anteriorly in the midline, what is the most superficial part of the conus elasticus called?
This is called the cricothyroid ligament.
Where does the cricothyroid ligament arise from?
It arises from the circular cricoid base.
What does the conus elasticus end as?
It ends at a free upper border which forms the lower edge of the slit in the inner wall of the larynx.