CSD 155 LAB 6: Laryngeal Musculature

Question 1

extrinsic muscles

Answer 1

• one attachment is in our on the larynx
• function: position and support the larynx
• all extrinsic laryngeal muscles are paired except the mylohyoid
• all insert at the hyoid bone except the sternohyoid

Question 2

intrinsic muscles

Answer 2

• all attachments are in or on the larynx
• function: open the larynx and vocal folds for respiration and close the vocal folds for phonation, vary the length and tension of the vocal folds to change pitch, close the larynx against pressure
• all are paired except the transverse arytenoid muscle (one on either side)

Question 3

digastric

Answer 3

• *EXTRINSIC MUSCLE**
• *SUPRAHYOID MUSCLE**
• two bellies
• anterior belly of the digastric (abd): mandible to hyoid bone
• posterior belly of the digastric (PBD): mastoid process to hyoid bone

Question 4

geniohyoid

Answer 4

• *EXTRINSIC MUSCLE**
• *SUPRAHYOID MUSCLE**
• genio = chin
• superior the mylohyoid
• mandible to hyoid bone

Question 5

mylohyoid

Answer 5

• *EXTRINSIC MUSCLE**
• *SUPRAHYOID MUSCLE
• forms the floor of the mouth
• only unpaired extrinsic laryngeal muscle
• mandible to hyoid bone

Question 6

stylohyoid

Answer 6

• *EXTRINSIC MUSCLE**
• *SUPRAHYOID MUSCLE**
• superficial to the posterior belly of the digastric
• stylohyoid process to the hyoid bone

Question 7

thyrohyoid

Answer 7

• *EXTRINSIC MUSCLE**
• *INFRAHYOID MUSCLE**
• SPECIAL CASE: classified as infrahyoid per location; however, it can function to elevate or depress the larynx depending on where it is fixed
• thyroid cartilage to the hyoid bone

Question 8

sternohyoid

Answer 8

• *EXTRINSIC MUSCLE**
• *INFRAHYOID MUSCLE**
• manubrium of the sternum/end of clavicle to the hyoid bone

Question 9

omohyoid

Answer 9

• *EXTRINSIC MUSCLE**
• *INFRAHYOID MUSCLE**
• omo = shoulder
• two bellies
• inferior belly - scapula to intermediate tendon (connects the two bellies of the muscle)
• superior belly (intermediate tendon to the hyoid bone)

Question 10

sternothyroid

Answer 10

• *EXTRINSIC MUSCLE**
• *INFRAHYOID MUSCLE**
• NOTE: not connected to the hyoid bone
• located in the anterior neck, deep to the sternohyoid and omohyoid
• deepest infrahyoid muscle
• sternum to the thyroid

Question 11

cricothyroid (CT)

Answer 11

• *INTRINSIC MUSCLE**
• anterior lateral arch of the cricoid to the thyroid cartilage
• two parts:
• -> pars oblique: courses posteriorly and superiorly to insert into the inferior cornu of the thyoid cartilage
• -> pars recta: courses superiorly to insert into the thyroid lamina
• function: lengthens the vocal folds to increase pitch.
• *MAJOR MUSCLE FOR INCREASING PITCH**

Question 12

thyroidarytenoid

Answer 12

• *INTRINSIC MUSCLE**
• two parts
• -> vocalis
• —> inner surface of the thyroid angle to the vocal process of the arytenoids
• —> function: increases vocal fold tension to increase pitch
• —> forms the main mass of the vocal folds
• -> thyromuscularis
• —> thyroid angle to the muscular process of the arytenoids
• —> function: adducts and shortens the vocal folds

Question 13

lateral cricoarytenoid (LCA)

Answer 13

• *INTRINSIC MUSCLE**
• arch of the cricoid to the muscular process of the arytenoids
• function: adducts the vocal folds by pulling the arytenoid

Question 14

interarytenoids (IA)

Answer 14

INSTRINSIC MUSCLE
composed of two muscles
- transverse arytenoid
–> only unpaired intrinsic laryngeal muscle
–> posterior surface of the arytenoid to the opposite arytenoid
–> function: adducts vocal folds

Question 15

posterior cricoarytenoid (PCA)

Answer 15

• cricoid lamina to the muscular process of the arytenoids
• function: abducts the vocal folds by drawing the arytenoids posteriorly and laterally
• -> ONLY glottal abductor