Intrinsic Laryngeal Muscles

Question 1

Thyroarytenoid Muscles (function and innervation)

Answer 1

• Make up the bulk of the vocal folds
• Plays a role in vocal fold tension
• Can increase internal tension, without changing the length of the vocal fold
• Increase tension = increase pitch
• Plays a role in shortening and adducting the vocal folds (brings them together)
• Pulls arytenoid cartilage closer to thyroid cartilage, and brings the medial edges of the folds together

Origin: Thyroid cartilage

Insertion: Arytenoid cartilage

Innervation: Recurrent Laryngeal Nerve (branch of Vagus)

Question 2

Lateral Cricoarytenoid Muscles (function and innervation)

Answer 2

• Rotates the arytenoid cartilage, drawing muscular process forward and vocal process medially
• Adducts vocal folds

Origin: Upper border of the lateral arch of the cricoid cartilage

Insertion: Anterior surface of the muscular process of the arytenoid cartilage

Innervation: Recurrent Laryngeal Nerve

Question 3

Transverse Interarytenoid Muscles (function and innervation)

Answer 3

• Broad sheet of muscle, running horizontally
• Origin: Apex to base of one arytenoid cartilage
• Insertion: Apex to base of other arytenoid ca
• Innervation: Recurrent Laryngeal Nerve (branch of Vagus)
• Function: Moves the arytenoid cartilages towards midline
  
  • Adducts vocal folds

Question 4

Oblique Interarytenoid Muscles (function and innervation)

Answer 4

• Paired muscle, forms an X on the posterior aspect of the arytenoid cartilages
• Origin: Apex of one arytenoid cartilage
• Insertion: base of the other arytenoid cartilages
• Innervation: Recurrent Laryngeal Nerve (branch of Vagus)
• Function: Moves the arytenoid cartilages towards midline
• Adducts vocal folds

Question 5

Posterior Cricoarytenoid Muscles (function and innervation)

Answer 5

• Origin: Lamina of cricoid cartilages
• Insertion: Posterior aspect of muscular processes of arytenoid muscles
• Innervation: Recurrent Laryngeal Nerve
• Function: Pulls muscular process diagonally downward and toward the midline
  
  • Abducts the arytenoid cartilage
  • Abducts the vocal folds

Question 6

Cricothyroid Muscles (function and innervation)

Answer 6

• Located on the outer surface of the larynx
• Origin: Arch of cricoid cartilage
• Insertion: Caudal margin of the thyroid cartilages
• Innervation: Superior Laryngeal Nerve (branch of Vagus)
• Function: Move the cricothyroid joint
• Lengthens and tenses the vocal folds