CSD 2230 - Human Communication Disorders

CSD 2230

Laryngeal Structures

Laryngeal System - With the lungs providing the necessary air supply for speech, the larynx is responsible for phonation (production of voice).
- Primary Biological Functions
- Closes entry into trachea during swallow
- Cough reflex which expels foreign substances that enter trachea
- Normal Larynx
Structural Support of the Laryngeal System
- Hyoid bone - larynx appears to be suspended from the hyoid bone
- Thyroid cartilage - it forms the anterior and lateral walls of the larynx
- Cricoid cartlilage - is top ring of trachea.
- Arytenoid cartilage - 2 pyramid-shaped cartilages, which are connected to cricoid through cricoarytenoid joint, which permits circular and sliding movements.
Vocal Folds - The folds are composed of several tissue layers that form a medial vocal ligament, but their bulk is formed by the vocalis muscle.
- Glottis space between folds
Laryngeal Musculature
- Extrinsic Muscles - support the larynx
  - Thyrohyoid - Depresses Thyroid
  - Sternothyroid - Depresses Hyoid
- Supplemental Muscles - (Fig 2.9 Owens 2000)
  - Depresses Hyoid
    - Omohyoid
    - Sternohyoid
  - Elevates Hyoid
    - Digastric
    - Mylohyoid
    - Stylohyoid
- Intrinsic Muscles are critical for modification of pitch and loudness
  - Muscles that separates (abducts) vocal folds
    - Posterior cricoarytenoid muscle (Fig 2-20, Fucci 1999), contraction rotates arytenoid cartilages laterally to separate vocal folds.
  - Muscles that brings (adducts) vocal folds together
    - Lateral cricoarytenoid and interarytenoid (Fig 2-21, Fucci 1999)
  - Muscles that tenses the vocal folds
    - Thyroarytenoid muscle - contraction toward anterior section of thryoid cartilage will tense the vocal folds and raise pitch
    - Cricothyroid msucle - contraction pulls thyroid cartilage down to stretch vocal folds and raise pitch (Fig 2-23, Fucci 1999)
Resources

[an error occurred while processing this directive][an error occurred while processing this directive]