Cartilage of larynx

CARTILAGE OF LARYNX

Q. 1

The narrowest part of trachea in a newborn is at the level of:

 A

Cricoid

 B

Thyroid

 C

Vocal cords

 D

Subglottic

Q. 1

The narrowest part of trachea in a newborn is at the level of:

 A

Cricoid

 B

Thyroid

 C

Vocal cords

 D

Subglottic

Ans. A

Explanation:

Neonates and infants have, compared with older children and adults, a proportionately larger head and tongue, narrower nasal passages, an anterior and cephalad larynx (the glottis is at a vertebral level of C4 versus C6 in adults),
a longer epiglottis, and a shorter trachea and neck.
These anatomic features make neonates and young infants obligate nasal breathers until about 5 months of age.
The cricoid cartilage is the narrowest point of the airway in children younger than 5 years of age; in adults, the narrowest point is the glottis. One millimeter of mucosal edema will have a proportionately greater effect on gas flow in children because of their smaller tracheal diameters.
 
Ref: Butterworth IV J.F., Butterworth IV J.F., Mackey D.C., Wasnick J.D., Mackey D.C., Wasnick J.D. (2013). Chapter 42. Pediatric Anesthesia. In J.F. Butterworth IV, J.F. Butterworth IV, D.C. Mackey, J.D. Wasnick, D.C. Mackey, J.D. Wasnick (Eds), Morgan & Mikhail’s Clinical Anesthesiology, 5e.

Q. 2

Which of the following is MOST important in separating the esophagus from the larynx, and must consequently be carefully passed behind during endoscopy?

 A

Arytenoids

 B

Cricoid cartilage

 C

Epiglottis

 D

Pharynx

Q. 2

Which of the following is MOST important in separating the esophagus from the larynx, and must consequently be carefully passed behind during endoscopy?

 A

Arytenoids

 B

Cricoid cartilage

 C

Epiglottis

 D

Pharynx

Ans. C

Explanation:

Endoscopists are very careful when guiding the endoscope past the epiglottis, which is a pear-shaped portion of elastic cartilage that can be moved during swallowing to close the larynx, preventing swallowed material from eventually entering the lungs.

  • The arytenoids are the site of the attachment of the vocal cords  within the larynx.
  • The cricoid cartilage is in the more distal portion of the larynx.
  • The pharynx is shared by the respiratory and gastrointestinal tracts.
Also know:
  • The thyroid cartilage forms a median elevation, called the laryngeal prominence (“Adam’s apple”), and lies inferior to the hyoid bone.
  • The epiglottis is an elastic cartilage, shaped like a spoon, that is posterior to the root of the tongue.
  • The cricoid cartilage is shaped like a signet ring, with the broad part of the ring facing posteriorly.
  • The arytenoid cartilages are shaped like a pyramid.

Q. 3

Which of the following is an example of hyaline cartilage?

 A

Epiglottis

 B

Thyroid cartilage

 C

Apex of Arytenoid Cartilage

 D

Pinna

Q. 3

Which of the following is an example of hyaline cartilage?

 A

Epiglottis

 B

Thyroid cartilage

 C

Apex of Arytenoid Cartilage

 D

Pinna

Ans. B

Explanation:

Thyroid cartilage is a type of hyaline cartilage. Hyaline cartilage is the most common type of cartilage, in adults this is replaced by bone by a process called enchondral ossification. In the articular surface of bone, costal cartilage, nose, larynx, trachea and bronchi hyaline cartilage persist throughout life and does not calcify.

Elastic cartilage: is highly flexible and is found in the external ear, walls of auditory tube, epiglottis and larynx.

Fibrocartilage is present in the intervertebral disc, pubis symphysis and certain joints.


Q. 4

Which of the following are true about larynx:

 A

Epiglottis cartilage is hyaline

 B

Thyroid cartilage is elastic

 C

Cricoid cartilage is elastic

 D

Cuneiform & cornculate cartilage are elastic

Q. 4

Which of the following are true about larynx:

 A

Epiglottis cartilage is hyaline

 B

Thyroid cartilage is elastic

 C

Cricoid cartilage is elastic

 D

Cuneiform & cornculate cartilage are elastic

Ans. D

Explanation:

D i.e. Cuneiform & cornculate cartilage are elastic

Elastic cartilage is found in sites which are concerned either with production or reception of sound eg. auricle (pinna), external acoustic meatus (lateral part), auditory tube , epiglottis & two small laryngeal cartilage (corniculate & cuneiform)


Q. 5

The oesophgus commences at the following level‑

 A

Lower end of cricoid

 B

C5 vertebra

 C

10cm from incisor teeth

 D

C7

Q. 5

The oesophgus commences at the following level‑

 A

Lower end of cricoid

 B

C5 vertebra

 C

10cm from incisor teeth

 D

C7

Ans. A

Explanation:

A. i.e. Lower end of Cricoid


Q. 6

Laryngeal cartilage forming complete circle:

 A

Arytenoid

 B

Cricoid

 C

Thyroid

 D

Hyoid

Q. 6

Laryngeal cartilage forming complete circle:

 A

Arytenoid

 B

Cricoid

 C

Thyroid

 D

Hyoid

Ans. B

Explanation:

 

Thyroid cartilage        V shaped on cross section. Has 2 lamina right and left which are placed at an angle of 90° in males and 120° in females

Cricoid cartilage         Ring shaped, (it is the only complete ring present in the air passages)

Epiglottic cartilage     Leaf shaped in adults, omega shaped in infants and neonates

Arytenoid cartilage     Pyramid shaped

Corniculate cartilage   Cone shaped

Cuneiform cartilage    Rod shaped

  • The thyroid, cricoid and basal parts of arytenoid cartilages are made up of hyaline cartilage. They ossify after the age of 25 years.
  • The other cartilages, e.g. epiglottis, corniculate, cuneiform and processes of the arytenoid are made of elastic cartilage and do not ossify.



Q. 7

True about larynx in neonate:

 A

Epiglottis is large and omega shaped

 B

Cricoid narrowest part

 C

It extends till C4,5,6 vertebrae

 D

a and b

Q. 7

True about larynx in neonate:

 A

Epiglottis is large and omega shaped

 B

Cricoid narrowest part

 C

It extends till C4,5,6 vertebrae

 D

a and b

Ans. D

Explanation:

 

Infant’s Larynx Differs from Adult in:

1. It is situated high up (C2 – C4).° (in adults = C3 – C6)

2. Of equal size in both sixes (in adults it is larger in males)

3. Larynx is funnel shaped

4. The narrowest part of the infantile larynx is the junction of subglottic larynx with trachea and this is because cricoid cartilage is very small

5. Cartilages:

    1. Epiglottis is omega shaped, soft, large and patulous.
    2. Laryngeal cartilages are soft and collapse easily
    3. Thyroid cartilage is flat
    4. Arytenoid cartilage is relatively large

6. The cricothyroid and thyrohyoid spaces are narrow

7. The submucosal tissue is thick and loose and becomes oedematous in response to inflammation

8. Vocal cords are angled and lie at level of C8

9. Trachea bifurcates at level of T9



Q. 8

Narrowest part of infantile larynx is:

 A

Supraglottic

 B

Subglottic

 C

Glottic

 D

None of the above

Q. 8

Narrowest part of infantile larynx is:

 A

Supraglottic

 B

Subglottic

 C

Glottic

 D

None of the above

Ans. B

Explanation:

 

The diameter of cricoid cartilage is smaller than the size of glottis, making subglottis the narrowest part


Q. 9

True regarding elastic cartilage are all EXCEPT:

March 2013

 A

Made up of yellow elastic fibres

 B

More pliable

 C

Highly vascular

 D

Found in inlet of larynx

Q. 9

True regarding elastic cartilage are all EXCEPT:

March 2013

 A

Made up of yellow elastic fibres

 B

More pliable

 C

Highly vascular

 D

Found in inlet of larynx

Ans. C

Explanation:

Ans. C i.e. Highly vascular

Cartilage has no blood vessels, lymphatics or nerves


Q. 10

Which of the following cartilage encircles the larynx‑

 A

Cricoid

 B

Epiglottis

 C

Thyroid

 D

Corn iculate

Q. 10

Which of the following cartilage encircles the larynx‑

 A

Cricoid

 B

Epiglottis

 C

Thyroid

 D

Corn iculate

Ans. A

Explanation:

Ans. is ‘a’ i.e., Cricoid

Cricoid cartilage is the only cartilage that forms a complete ring.

Laryngeal cartilages

Thyroid (unpaired)

  • It is the largest of all laryngeal cartilages. It is ‘V’ shaped with right and left lamina. Both laminae (alae) meet anteriorly forming an angle of 90° in males and 120° in females and forms laryngeal prominence. Vocal cords are attached to the middle of thyroid angle. Upper border of thyroid cartilage lies at C5-C4 junction (at upper border of C4). Thyroid cartilage itself lies at C4-C5 level.

Cricoid (unpaired)

  • It is the only cartilage forming a complete ring, therefore is shaped like a ring. It articulates with arytenoid cartilage to form cricoarytenoid joint, a type of synovial joint. It lies at the level of C6 vertebra.

Epiglottis (unpaired)

  • It is leaf-shaped elastic cartilage (in adults). It is omega shaped in children. It forms the anterior wall of laryngeal inlet. It lies above glottis.

Arytenoid cartilage (paired)

  • Each Arytenoid cartilage is pyramidal in shape. Base articulates with cricoid cartilage, and apex supports the corniculate cartilage. A vocal process directed anteriorly and gives attachement to vocal cord. A muscular process directed laterally and gives attachment to intrinsic laryngeal muscles.
  • Corniculate cartilage (of Santorini) : Paired
  • Articulates with apex of Arytenoid cartilage
  • Cuneiform cartilage (of Wrisberg) : Paired
  • Situated in aryepiglottic fold in front of corniculate cartilage.


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