Muscles of larynx

MUSCLES OF LARYNX

Q. 1

Abductor of vocal cord is

 A

Posterior cricoarytenoid 

 B

Cricothyroid

 C

Interarytenoid

 D

Lateral cricoaretynoid

Q. 1

Abductor of vocal cord is

 A

Posterior cricoarytenoid 

 B

Cricothyroid

 C

Interarytenoid

 D

Lateral cricoaretynoid

Ans. A

Explanation:

 

INTRINSIC MUSCLES ACTING ON VOCAL CORDS:

Abductors

Posterior cricoarytenoid

Adductors

Lateral cricoarytenoid, Interarytenoid (transverse arytenoid) Thyroarytenoid

(external part)

Tensors

Cricothyroid Vocalis (internal part of thyroarytenoid)

 

INTRINSIC MUSCLES ACTING ON LARYNGEAL INLET:

Openers of laryngeal inlet

Thyroepiglottic (part of thyroarytenoid)

Closers of larylngeal inlet

Interarytenoid (oblique part), Aryepiglottic (posterior

oblique part of interarytenoids)


Q. 2  All  of  the  following  muscles are  attached to oblique line of thyroid cartilage except
 A Superior constrictor
 B . Inferior constrictor
 C Thyrohyoid
 D Stern thyroid
Q. 2  All  of  the  following  muscles are  attached to oblique line of thyroid cartilage except
 A Superior constrictor
 B . Inferior constrictor
 C Thyrohyoid
 D Stern thyroid
Ans. A

Explanation:

Superior constrictor

MUSCLE

Superior constrictor (Constrictor

of pharynx)

ORIGIN

i. Pterygoid hamulus

ii. Pterygomandibular raphe

iii. Medial surface of mandible (near lower      attachment of pterygomandibular raphe

INSERTION

Median raphe on posterior wall of

pharynx

Inferior constrictor (Constrictor of

Two parts: pharynx)

i. Thyropharyngeus – from thyroid

cartilage (oblique line of thyroid cartilage)

ii. Cricopharyngeus  –  from  cricoid

cartilage

Median raphe on posterior wall of

pharynx

Sternothyroid (Infrahyoid muscle)

i. Posterior surface of manubrium

sterni

ii. Adjoining  part  of  first  costal cartilage

Oblique line of thyroid cartilage

Thyrohyoid (Infrahyoid muscle)

Oblique line of thyroid cartilage

Lower border of body and greater

cornua of hyoid bone


Q. 3

Abductor of the larynx is:

 A

Crico-arytenoideus posterior

 B

Crico-arytenoideus lateralis

 C

Arytenoideus transversus

 D

Vocalis muscle

Q. 3

Abductor of the larynx is:

 A

Crico-arytenoideus posterior

 B

Crico-arytenoideus lateralis

 C

Arytenoideus transversus

 D

Vocalis muscle

Ans. A

Explanation:

Q. 4

Which is the only muscle that is located on the external aspect of larynx?

 A

Cricothyroid

 B

Lateral cricoarytenoid

 C

Thyroarytenoid

 D

Posterior cricoarytenoid

Q. 4

Which is the only muscle that is located on the external aspect of larynx?

 A

Cricothyroid

 B

Lateral cricoarytenoid

 C

Thyroarytenoid

 D

Posterior cricoarytenoid

Ans. A

Explanation:

Cricothyroid is the only muscle that is located on the external aspect of larynx. it is supplied by the external laryngeal nerve. It is a tensor and mild adductor of the vocal cord. 
 
Abductor of vocal cord:
  • Posterior cricoarytenoid
Adductors of vocal cord are:
  • Cricothyroid
  • Thyroarytenoids
  • Lateral cricoarytenoid
  • Transverse arytenoids
Relaxant of vocal cords:
  • Vocalis
  • Thyroarytenoid

Q. 5

Which one of the following muscle is functioning as tensor of vocal cord during phonation?

 A

Post cricoarytenoid

 B

Interarytenoid

 C

Lateral cricothyroid

 D

Cricothyroid

Q. 5

Which one of the following muscle is functioning as tensor of vocal cord during phonation?

 A

Post cricoarytenoid

 B

Interarytenoid

 C

Lateral cricothyroid

 D

Cricothyroid

Ans. A

Explanation:

Major Muscles of the Larynx:

Muscle

Function

Innervation

Key Point

Posterior cricoarytenoid

Abducts, tenses vocal folds

Recurrent laryngeal nerve

Only abductor of vocal folds 

Lateral cricoarytenoid

Adducts true vocal folds

Recurrent laryngeal nerve

 

Interarytenoid

Adducts posterior glottis

Recurrent laryngeal nerve

Only laryngeal muscle receiving bilateral innervation 

Oblique arytenoids

Closes laryngeal inlet during swallowing

Recurrent laryngeal nerve

 

Thyroarytenoid

Adducts, tenses vocal fold

Recurrent laryngeal nerve

 

Cricothyroid

Increases vocal fold tension, especially at higher pitches

External branch of superior laryngeal nerve

Only muscle not innervated by recurrent laryngeal nerve 


Q. 6

Which of the following muscle is known as safety muscle of larynx?

 A

Cricothyroid

 B

Thyroarytenoid

 C

Lateral cricoarytenoid

 D

Posterior cricoarytenoid

Q. 6

Which of the following muscle is known as safety muscle of larynx?

 A

Cricothyroid

 B

Thyroarytenoid

 C

Lateral cricoarytenoid

 D

Posterior cricoarytenoid

Ans. D

Explanation:

Posterior cricoarytenoid is known as safety muscle of larynx. It is so called because being the only abductor of the vocal cords it keeps the rima glottis open to allow air to enter the lungs.
 
Adductors of vocal cord are:
  • Cricothyroid
  • Thyroarytenoids
  • Lateral cricoarytenoid
  • Transverse arytenoids
Relaxant of vocal cords:
  • Vocalis
  • Thyroarytenoid

Q. 7

Which of the following muscle of the larynx acts as abductor of vocal cords?

 A

Lateral cricoarytenoid

 B

Posterior cricoarytenoid

 C

Anterior cricoarytenoid

 D

Cricothyroid

Q. 7

Which of the following muscle of the larynx acts as abductor of vocal cords?

 A

Lateral cricoarytenoid

 B

Posterior cricoarytenoid

 C

Anterior cricoarytenoid

 D

Cricothyroid

Ans. B

Explanation:

Posterior cricoarytenoid is the sole abductor of vocal cords. Therefore bilateral paralysis may lead to adduction of vocal cords and suffocation. They are called safety muscles of larynx.
 
It arise from the posterior surface of lamina of cricoid on either side of midline, and is inserted on back of the muscular process of arytenoid cartilage of its side. It acts on cricoarytenoid joint to rotate the arytenoid with its vocal process laterally so  that muscular process turns posteriorly resulting in abduction of vocal cords and widening of rima glottis.
 
Adductors of vocal cord:
  • Lateral cricoarytenoid
  • Transverse arytenoid

Q. 8

All the muscles of the larynx are supplied by the recurrent laryngeal nerve, EXCEPT?

 A

Cricothyroid

 B

Salpingopharyngeus

 C

Stylopharyngeus

 D

None of the above

Q. 8

All the muscles of the larynx are supplied by the recurrent laryngeal nerve, EXCEPT?

 A

Cricothyroid

 B

Salpingopharyngeus

 C

Stylopharyngeus

 D

None of the above

Ans. A

Explanation:

All the intrinsic muscles of the larynx are supplied by the recurrent laryngeal nerve except for cricothyroid, which is supplied by the external laryngeal nerve.

 


Q. 9

Adductors of vocal cord

 A

Posterior cricoarytenoids

 B

Cricothyroid

 C

Transverse arytenoids

 D

Voccalis

Q. 9

Adductors of vocal cord

 A

Posterior cricoarytenoids

 B

Cricothyroid

 C

Transverse arytenoids

 D

Voccalis

Ans. C

Explanation:

 Transverse (oblique) arytenoids


Q. 10

All are elevators of larynx except:

 A

Thyrohyoid

 B

Digastric

 C

Stylohyoid

 D

mylohyoid

Q. 10

All are elevators of larynx except:

 A

Thyrohyoid

 B

Digastric

 C

Stylohyoid

 D

mylohyoid

Ans. A

Explanation:

 

 The main laryngeal elevators are: Digastric anterior and posterior, the stylohyoid, mylohyoid, geniohyoid, genioglossus, hyoglossus, and thyropharyngeus muscles


Q. 11

Sensory nerve supply of larynx below the level of vocal cord is:

 A

External branch of superior laryngeal nerve

 B

Internal branch of superior laryngeal nerve

 C

Recurrent laryngeal nerve

 D

Inferior pharyngeal

Q. 11

Sensory nerve supply of larynx below the level of vocal cord is:

 A

External branch of superior laryngeal nerve

 B

Internal branch of superior laryngeal nerve

 C

Recurrent laryngeal nerve

 D

Inferior pharyngeal

Ans. C

Explanation:

 

Nerve supply of larynx

  • Sensory:

The internal laryngeal nerve supplies the mucous membrane up to the level of the vocal folds.

–  The recurrent laryngeal nerve supplies below the level of the vocal folds.

  • Motor:

–  All intrinsic muscles of the larynx are supplied by the recurrent laryngeal nerve except for the cricothyroid which is supplied by the external laryngeal nerve.



Q. 12

A patient met with recurrent laryngeal nerve palsy while undergoing thyroid surgery. Which of the following muscles of larynx is/are affected?

 A

Posterior crioarytenoid

 B

Lateral cricoarytenoid

 C

Thyroarytenoid

 D

All

Q. 12

A patient met with recurrent laryngeal nerve palsy while undergoing thyroid surgery. Which of the following muscles of larynx is/are affected?

 A

Posterior crioarytenoid

 B

Lateral cricoarytenoid

 C

Thyroarytenoid

 D

All

Ans. D

Explanation:

 

All muscles which move the vocal cord (abductors, adductors or tensors) are supplied by the recurrent laryngeal nerve except the cricothyroid muscle which is supplied by external laryngeal nerve (a branch of superior laryngeal nerve).



Q. 13

Which of the following is the only intrinisic muscle of larynx that lies outside the laryngeal framework?

 A

Cricothyroid

 B

Superior constrictor

 C

Cricopharyngeus

 D

Lateral cricothyroid

Q. 13

Which of the following is the only intrinisic muscle of larynx that lies outside the laryngeal framework?

 A

Cricothyroid

 B

Superior constrictor

 C

Cricopharyngeus

 D

Lateral cricothyroid

Ans. A

Explanation:

 

Cricothyroid muscle is the only intrinsic muscle which is supplied by external laryngeal nerve and lies outside the laryngeal framework


Q. 14

Safety muscle of larynx:  

 A

Lateral cricoarytenoid

 B

Transverse arytenoid

 C

Posterior cricoarytenoid

 D

Cricothyroids

Q. 14

Safety muscle of larynx:  

 A

Lateral cricoarytenoid

 B

Transverse arytenoid

 C

Posterior cricoarytenoid

 D

Cricothyroids

Ans. C

Explanation:

  • During forced inspiration, both parts of the rima are triangular, so that the entire rima is lozenge shaped; the vocal cords are fully abducted and we all know that muscles which open the glottis, are posterior cricoarytenoids. So in one way we can consider them as safety muscles which help in respiration (forced inspiration)

Q. 15

The muscle which is not supplied by this nerve(with arrow) in this image

 A

Thyroarytenoid


 B

Posterior cricoarytenoid


 C

Cricothyroid


 D

Lateral cricoarytenoid

Q. 15

The muscle which is not supplied by this nerve(with arrow) in this image

 A

Thyroarytenoid


 B

Posterior cricoarytenoid


 C

Cricothyroid


 D

Lateral cricoarytenoid

Ans. C

Explanation:

Nerve is Recurrent laryngeal 

  • Thyroarytenoid muscle:- R and L muscles; attached to thyroid and arytenoid cartilages on each side.
  • Lateral cricoarytenoid muscle: (R and L muscles):–  Attached to cricoid and arytenoid cartilage on each side. Closes or adducts vocal folds. Supplied by Recurrent laryngeal nerve
  • Cricothyroid muscle: Attached to cricoid and thyroid cartilages. Tilts the thyroid cartilage, thus increasing tension of vocal folds
  • Posterior cricoarytenoid muscleAttached to cricoid and arytenoid cartilages Move arytenoid cartilages so as to move both vocal folds apart, “open” of abduct vocal foldsSupplied by Recurrent laryngeal nerve

Q. 16

Nerve supply of larynx above level of vocal cord

 A

Superior laryngeal 

 B

Recurrent laryngeal

 C

Glossopharyngeal

 D

External laryngeal

Q. 16

Nerve supply of larynx above level of vocal cord

 A

Superior laryngeal 

 B

Recurrent laryngeal

 C

Glossopharyngeal

 D

External laryngeal

Ans. A

Explanation:

Ans. is ‘a’ i.e., Superior laryngeal 

Nerve supply of larynx

  • The main cranial nerve innervating the larynx is the vagus nerve via its branches; superior laryngeal nerve (SLN) and recurrent laryngeal nerve (RLN).
  • Sensory supply of larynx
  • Above the level of vocal cords, larynx is supplied by internal laryngeal nerve, a branch of superior laryngeal nerve.
  • Below the vocal cord, larynx is supplied by recurrent laryngeal nerve.
  • Motor supply of larynx
  • All the intrinsic muscles of larynx are supplied by recurrent laryngeal nerve except for cricothyroid muscle. 
  • Cricothyroid is supplied by external laryngeal nerve, a branch of superior laryngeal nerve.

Q. 17

Which muscle of larynx is not supplied by recurrent laryngeal nerve ‑

 A

Vocalis

 B

Thyroarytenoid

 C

Cricothyroid

 D

Interarytenoid

Q. 17

Which muscle of larynx is not supplied by recurrent laryngeal nerve ‑

 A

Vocalis

 B

Thyroarytenoid

 C

Cricothyroid

 D

Interarytenoid

Ans. C

Explanation:

Ans. is ‘c’ i.e., Cricothyroid 

  • All intrinsic muscles are supplied by the reccurrent laryngeal nerve except cricothyroid which is supplied by the external laryngeal nerve


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