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

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.

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.

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

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

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

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

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

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

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

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

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

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

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.

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

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.

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).

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.

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.

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.

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.

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

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?

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?

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?

Section 3: Lecture 1; Anatomy & physiology of voice production. Reading/Assignments Seikel: Pgs. 183-202 Dickson: Pgs. 160-176