1. Section 3: Lecture 1; Anatomy & physiology of voice production.
Laryngeal Anatomy

2. Extrinsic Laryngeal Muscles
Section 3: Lecture 1; Anatomy & physiology of voice production.
Extrinsic Laryngeal Muscles
Three Main Purposes:
1) Fixation (primary role)
2) Elevation (move larynx up)
3) Depression (move larynx down)
Two major groups of extrinsic muscles
Suprahyoid & Infrahyoid
Anatomical position:
Suprahyoid- one of the above attachments lies above the larynx.
Infrahyoid- one of the attachments lies below the larynx.

3. Extrinsic Laryngeal Muscles
Section 3: Lecture 1; Anatomy & physiology of voice production.
Extrinsic Laryngeal Muscles
Suprahyoid Muscles:
1) Digastric
2) Geniohyoid
3) Hyoglossus
4) Mylohyoid
5) Stylohyoid
Function: Raise the hyoid bone & indirectly raise the larynx.

4. Section 3: Lecture 1; Anatomy & physiology of voice production.
Digastric
Two fleshy bellies
Anterior belly- originates from the inside surface of the lower border of the mandible near the symphysis and inserts into the lesser horn of the hyoid bone
Posterior belly- Originate from the mastoid process of the temporal bone to the sternocleidomastoid muscle
Two bellies meet and are joined by an intermediate tendon
Contraction raises hyoid or if hyoid is fixed, may assist in depressing lower jaw

5. Section 3: Lecture 1; Anatomy & physiology of voice production.
Stylohyoid
Superficial to the diagastric
Originates from posterior and lateral surface of the styloid process of the temporal bone & inserts into hyoid bone
Contraction draws the hyoid bone up and backward

6. Section 3: Lecture 1; Anatomy & physiology of voice production.
Mylohyoid
Forms muscular floor of mouth
Originate from the mylohyoid line (inner surface of mandible)
Fibers coarse medially and downward and join the other paired muscle at the raphe
Posterior fibers attach right to hyoid bone
Contraction elevates the hyoid, floor of mouth and tongue
Hyoid fixed, may assist in depressing mandible

7. Section 3: Lecture 1; Anatomy & physiology of voice production.
Geniohyoid
Paired, cylindrical muscle located above the superior surface of the mylohyoid muscle
Originate by means of a short tendon, from the lower part of the mental symphysis
Insert into anterior surface of the hyoid
Mandible fixed, this muscle pulls the hyoid bone up and forward

8. Section 3: Lecture 1; Anatomy & physiology of voice production.
Hyoglossus
Extrinsic muscle of the tongue
Influences position of the larynx
Arises from upper border of the body and greater horns of the hyoid bone
Inserts into posterior and lateral regions of the tongue

9. Section 3: Lecture 1; Anatomy & physiology of voice production.
Genioglossus
Extrinsic tongue muscle which influences position of the larynx
Originates from the mental symphysis
Fibers fan out and course toward their insertion
Lower fibers insert into the body of the hyoid bone
Upper fibers insert into the under surface of the tongue
Contraction elevates the hyoid bone and draws it forward

10. Section 3: Lecture 1; Anatomy & physiology of voice production.
Infrahyoid Muscles:
1) Sternohyoid
2) Omohyoid
3) Sternothyroid
*All are considered laryngeal depressors

11. Section 3: Lecture 1; Anatomy & physiology of voice production.
Sternohyoid
Flat muscle lying on the anterior surface of the neck
Originates from the posterior surface of the manubrium of the sternum from the medial end of the clavicle and from the ligamentus tissue
Fibers coarse vertically and insert on the lower border of the body of the hyoid
Acts to draw the hyoid bone downward and fixes the hyoid when the lower jaw is open against resistance

12. Section 3: Lecture 1; Anatomy & physiology of voice production.
Omohyoid
Long, narrow 2 bellied muscle
Located on the anterolateral surface of the neck
Inferior belly originates from the upper horn of the hyoid
Prevents the neck region from collapsing during deep inspiration
Prevents blood vessels of the neck from being compressed

13. Extrinsic laryngeal Muscles
Section 3: Lecture 1; Anatomy & physiology of voice production.
Extrinsic laryngeal Muscles
Mandible
Mastoid Tip
Mylohyoid
Hyoid Bone
Sternohyoid
Omohyoid
Sternum
Ant.
Digastric
Post.
Digastric
Stylohyoid
Thyrohyoid
Sternothyroid

14. Intrinsic Laryngeal Muscles
Section 3: Lecture 1; Anatomy & physiology of voice production.
Intrinsic Laryngeal Muscles
Functions:
1) Abduction of the vocal folds for respiration,
2) Fine discrete movements during voice production & closure of the vocal folds and,
3) Protection of the trachea.

15. Section 3: Lecture 1; Anatomy & physiology of voice production.
More Specifically...
change the degree of abduction/ adduction
change the mass characteristics of the folds
change the tension of the folds
change the length characteristics of the folds
react during swallowing- closure of folds
assist in muscular mechanical advantage

16. Section 3: Lecture 1; Anatomy & physiology of voice production.
Intrinsic Muscles:
Action of Cricothyroid
Pars oblique
Pars recta
Cricothyroid: fan-shaped, 2 divisions, Lengthens & tenses the vocal folds.

17. Section 3: Lecture 1; Anatomy & physiology of voice production.
Intrinsic Muscles
Vocal ligament
Thyroarytenoid
Thyrovocalis
Thyromuscularis
Thyroarytenoid: muscle making up the true vocal folds, 2 parts: thyrovocalis (bound to the vocal ligament) & thyromuscularis (lateral to arytenoids).

18. Thyroarytenoid Functions
Section 3: Lecture 1; Anatomy & physiology of voice production.
Thyroarytenoid Functions
decreases the distance between the thyroid & arytenoid cartilage's,
shortens the folds,
decreases tension
decreases pitch of the voice,
active contraction lowers pitch of the voice.

19. Section 3: Lecture 1; Anatomy & physiology of voice production.
Intrinsic Muscles
Action of Post.
Cricoarytenoid
Posterior
Cricoarytenoid
Posterior Cricoarytenoid: Abducts the vocal folds, actively contracted at the end of phonation & any speech sound not requiring v.f. vibration.

20. Section 3: Lecture 1; Anatomy & physiology of voice production.
Intrinsic Muscles
Action of Lat.
Cricoarytenoid
Lateral
Cricoarytenoid
Lateral Cricoarytenoid: lies along upper surface of cricoid cartilage, adducts vocal processes of arytenoids closing membranous portion of v.f.’s.

21. Section 3: Lecture 1; Anatomy & physiology of voice production.
Intrinsic Muscles
Transverse
Interarytenoids
Oblique
Interarytenoids
Interarytenoids (transverse & oblique): Unpaired, 2 part muscle, adducts the v.f.’s in the cartilaginous portion by pulling arytenoid tips together.

22. Section 3: Lecture 1; Anatomy & physiology of voice production.
The Glottis
Glottis
The glottis is an open space between the vocal folds.
Size is dependent on what position the v.f.’s are in.
Not a muscle or cartilage.
Abduction- open v.f.’s; Adduction- closed v.f.’s

23. Section 3: Lecture 1; Anatomy & physiology of voice production.
Ventricular Folds
Otherwise know as the False Folds,
superior & lateral to the true vocal folds,
Their role in phonation?
-No role in voicing
consist of muscle, but doesn’t have innervation for discrete movements,
Hyperfunctional voice?

24. Section 3: Lecture 1; Anatomy & physiology of voice production.
Activity
1) With you mouth open, hold your breath, then abruptly release it with a vocal tone. What physiologic events occur at the glottis?
2) Produce an /h/ sound alone. What is the status of the glottis? How did it get there?
3) Produce an /h/ sound, then slide into phonation. What muscles are contracting to affect what conditions in the glottis?

25. Section 3: Lecture 1; Anatomy & physiology of voice production.
More questions...
1) Place your finger on the laryngeal prominence, alternate between high and low pitched tones. Can you identify a change in the position of the larynx and describe the prime movers?
2) Can you phonate while inhaling? What are the physiological differences?

26. Section 3: Lecture 1; Anatomy & physiology of voice production.
Reading/Assignments
Seikel: Pgs
Dickson: Pgs