SALC07 Biological Sciences Head & Neck 4 Larynx & Phonation Marianne Bos-Clark [email protected]

Larynx/Phonation Sources/Reading • Atkinson & McHanwell (2002) Basic Medical Science for SLT students London: Whurr Ch.16 Neck/Larynx Ch.17 Phonation • Mathieson (2001) Greene & Mathiesosn’s The Voice & Its Disorders London: Whurr Ch.2 Larynx/ Upper resp. tract Ch.4 Voice and phonation • Standard anatomy/physiology texts • Internet

Larynx/Phonation • Structure Lx: Cartilages Muscles Vocal folds Innervation • Function: Vocal folds Normal voice production Voice quality

The larynx

Larynx- lateral view

Larynx – anterior view

Larynx – posterior view

Larynx – posterior & from above

Laryngeal Cartilages 9 cartilages, 3 unpaired, 3 paired • Thyroid cartilage • Cricoid cartilage • Epiglottis • Arytenoid cartilages • Minor cartilages: corniculate & cuneiform

Laryngeal structure Laryngeal membranes • Thyrohyoid membrane • Cricotracheal membrane • Cricothyroid membrane ligament Laryngeal Joints • Cricothyroid • Cricoarytenoid

Larynx – anterior view Thyrohyoid membrane Cricotracheal membrane Cricothyroid membrane ligament

Larynx – posterior view

Laryngeal inlet • Laryngeal vestibule • infra/supra-glottis • True VF • False VF/vestibular folds • Ventricular/laryngeal sinus

The larynx vocal fold (left/right); ventricular fold; trachea; epiglottis; arytenoid cartilage;

Extrinsic Laryngeal Muscles • Suprahyoid (elevators) Digastric Stylohyoid Mylohyoid Geniohyoid • Infrahyoid (depressors) Sternohyoid Sternothyroid Omohyoid Thyrohyoid

Intrinsic Laryngeal Muscles: thyroarytenoid

Intrinsic Laryngeal Muscles: posterior & lateral cricoarytenoids

Posterior & Lateral Cricoarytenoid

Intrinsic Laryngeal Muscles: interarytenoid muscles oblique arytenoids transverse arytenoid aryepiglotticus

Intrinsic Laryngeal Muscles: cricothryroid

Vocal Fold Histology

VF Histology

Vocal Folds: membranous and cartilaginous portion

Laryngeal Innervation X Vagus All innervation intrinsic laryngeal muscles Sensory structures Lx

Laryngeal Innervation X Vagus • Superior laryngeal nerve: internal & external superior branches • Left & right recurrent laryngeal nerve

Phonation

Phonation

Phonation

Self-study Activity • Explore the larynx on Anatomy TV • Make sure you have a good understanding of the basic structure and function of the larynx, as well as the methods of examination used by ENT/Specialist SLTs

Self-study Activity • Construct your own larynx from the template, following the instructions provided • Explain the structure of the larynx to someone, using your model of the larynx as a tool • Explain how normal voice is produced, using your model and other tools to illustrate your explanation

Phonation: Voice quality Judging voice quality on perceptual scales such as the GRBAS (Hirano 1986) Grade Rough Breathy Asthenia Strain 0=normal; 1=mild; 2=moderate; 3=severe