PHYSIOLOGY OF PHONATION PRESENTATION PPT

1. Introduction
Phonation is the physiological process by which the human larynx generates sound, forming the basis for speech and vocal communication. It involves a complex interplay between respiratory airflow, laryngeal muscle activity, vocal fold vibration, and resonance in the vocal tract. The phenomenon of phonation transforms aerodynamic energy from exhaled air into acoustic energy, producing the fundamental tone of the voice. Subsequent modification by supralaryngeal structures—the pharynx, oral cavity, and nasal cavity—results in articulated speech.
Phonation is both a neuromuscular and aerodynamic process. It depends on precise coordination among the respiratory system (power source), the larynx (vibrator), and the supraglottic vocal tract (resonator and articulator). Understanding its physiology is fundamental to medicine, speech pathology, linguistics, and voice sciences.
2. Functional Anatomy of the Larynx
2.1. Position and Structure
The larynx, located in the anterior neck opposite the C3–C6 vertebrae, serves as the organ of phonation. It connects the pharynx above to the trachea below. Structurally, it consists of cartilages, intrinsic and extrinsic muscles, ligaments, and a mucosal lining.
2.2. Cartilages of the Larynx
The laryngeal framework is composed of nine cartilages—three unpaired and three paired:
Unpaired: Thyroid, Cricoid, Epiglottis
Paired: Arytenoid, Corniculate, Cuneiform
1. Thyroid Cartilage
Largest laryngeal cartilage.
Comprises two laminae meeting at the laryngeal prominence (“Adam’s apple”).
Provides anterior attachment for vocal folds via the thyroid angle.
2. Cricoid Cartilage
Signet-ring shaped, forming the base of the laryngeal framework.
Articulates with the thyroid cartilage (cricothyroid joint) and arytenoids (cricoarytenoid joints).
3. Arytenoid Cartilages
Pyramid-shaped, perched atop the cricoid’s posterior lamina.
Each arytenoid has a vocal process (anteriorly) and muscular process (laterally), serving as attachment points for vocal ligaments and intrinsic muscles.
4. Epiglottis
Leaf-shaped elastic cartilage that guards the laryngeal inlet during swallowing.
5. Corniculate and Cuneiform Cartilages
Small nodules within the aryepiglottic folds, supporting the laryngeal inlet.
2.3. Joints and Ligaments
Cricothyroid joint allows rotation and gliding movements between the cricoid and thyroid cartilages, crucial for pitch modulation.
Cricoarytenoid joints permit the arytenoids to rotate and glide, enabling vocal fold abduction and adduction.
Ligaments and membranes—such as the conus elasticus, quadrangular membrane, and vocal ligament—connect these cartilages and contribute to the vibratory system.
Vocal Folds
The vocal folds (true vocal cords) are paired structures extending from the thyroid cartilage anteriorly to the arytenoid cartilages posteriorly. Each fold consists of:
Epithelium – stratified squamous, protecting against friction.
Lamina propria – divided into:
Superficial layer (Reinke’s space) – loose

1. PHYSIOLOGY OF PHONATION MODERATOR : DR. KULDEEP. PRESENTER : DR. ALOYSIUS.

2. INTRODUCTION VOICE VS SPEECH VOICE – NATURAL MEDIUM WELL ADAPTED TO COMMUNICATE EMOTIONAL CONTENT - A RESULT OF PHONATION SPEECH – CULTURAL MEDIUM SUITABLE TO CONVEY INTELLECTUAL CONTENT – A RESULT OF ARTICULATION.

3. PHONATION – RESONANCE – ARTICULATION. PHONATION – GENERATION OF SOUND BY VIBRATION OF VOCAL FOLDS. ‘LARYNGEAL MOTOR BEHAVIOR USED FOR SPEECH PRODUCTION INVOLVING A HIGHLY SPECIALISED CO-ORDINATION OF LARYNGEAL & RESPIRATORY NEUROMUSCULAR CO-ORDINATION’ RESONANCE – THE INDUCTION OF VIBRATION IN THE REST OF THE VOCAL TRACT TO MODULATE LARYNGEAL OUTPUT. ARTICULATION – SHAPING OF VOICE INTO WORDS.

4. THEORIES OF PHONATION NEUROCHRONAXIC HYPOTHESIS. MYOELASTIC – AERODYNAMIC THEORY. BODY COVER PRINCIPLE. TWO MASS MODEL SOURCE FILTER HYPOTHESIS. ONE MASS MODEL (obsolete)

5. NEUROCHRONAXIC THEORY (RAOUL HUSSON, 1950) “GLOTTIC VIBRATIONS ARE CAUSED BY RHYTHMIC IMPULSES IN THE NERVES TO THE LARYNX. EACH VIBRATORY CYCLE – SEPARATE NEURAL IMPULSE. PHYSIOLOGICALLY IMPOSSIBLE – SO REJECTED

6. MYOELASTIC – AERODYNAMIC THEORY ( VAN DEN BERG, 1948) “INTERACTION OF AERODYNAMIC FORCES & THE MECHANICAL PROPERTIES OF THE LARYNGEAL TISSUES ARE RESPONSIBLE FOR INDUCING VOCAL FOLD VIBRATION & GENERATING VOCAL SOUND”.

7. RAPID ABDUCTION OF VOCAL CORDS ALLOW INTAKE OF AIR ADDUCTION OF VOCAL CORDS CONTRACTION OF THORACIC & ABDOMINAL MUSCLES AGAINST CLOSED VC PRE-PHONATORY INSPIRATORY PHASE

8. INCREASED SUBGLOTTIC PRESSURE OVERCOMES THE RESISTANCE OF VOCAL CORDS. ( PHONATION THRESHOLD PRESSURE ) OPENING OF VOCAL CORDS. RELEASE OF SMALL PUFFS OF AIR. MOVING AIR VIBRATES THE ELASTIC VOCAL CORDS. PRODUCTION OF SOUND LARYNGEAL PHASE

9. MODULATION OF SOUND BY LIPS, TONGUE, PHARYNX PALATE & TEETH SPEECH

10. THE BERNOUILLI EFFECT “ WHEN AIR PASSES FROM ONE LARGE SPACE TO ANOTHER (FROM LUNG TO PHARYNX), THROUGH A CONSTRICTION (THE GLOTTIS), THE VELOCITY WILL BE GREATEST & THE PRESSURE LEAST AT THE SITE OF THE CONSTRICTION”

11. BODY COVER THEORY OF MUCOSAL WAVE (HIRANO)

12. COVER – PLIABLE, ELASTIC, NON MUSCULAR. BODY – STIFF, ACTIVE CONTRACTILE PROPERTIES. ACCORDING TO BODY – COVER PRINCIPLE, THE BODY OF THE VOCAL FOLD IS RELATIVELY STATIC , WHEREAS THE WAVE IS PROPOGATED IN THE MUCOSAL COVER.

13. TWO MASS MODEL (ISHIZAKA & FLANAGAN ) THE MUCOSAL WAVE BEGINS ON THE INFEROMEDIAL ASPECT OF THE VOCAL FOLD & MOVES ROSTRALLY THERE IS A TEMPORAL RELATIONSHIP BETWEEN THE SUPERIOR & LOWER EDGES – AS SUPERIOR EDGES BEGIN TO SEPARATE, THE LOWER EDGES CLOSE. SUPERIOR EDGES SEPARATE - NEGATIVE PRESSURE OCCURS AT LOWER EDGES – LOWER EDGES CLOSE.

14. SOURCE FILTER HYPOTHESIS. “LARYNX IS THE SOURCE OF A CONSTANT SOUND, WHICH IS SHAPED INTO WORDS BY THE UPPER VOCAL TRACT.”

15. REQUIREMENTS OF PHONATION ADEQUATE BREATH SUPPORT. APPROXIMATION OF VOCAL FOLDS. FAVORABLE VIBRATORY PROPERTIES FAVOURABLE VOCAL CORD / FOLD SHAPE. CONTROL OF LENGTH & TENSION.

16. a) ADEQUATE BREATH SUPPORT: - VOLUME OF AIR IN THE LUNGS. - ELASTIC RECOIL OF CHEST WALL & DIAPRAGM. - STRENGTH IN ABDOMINAL & INTERCOASTAL MUSCLES. LUNG CAPACITY > BREATH SUPPORT NEEDED FOR NORMAL CONVERSATIONS.

17. b) VOCAL FOLD POSITIONING / APPROXIMATION. FOLDS SHOULD BE CLOSE ENOUGH TOGETHER SO THAT AIRFLOW PRODUCES OSSCILATIONS. TOO WIDE A GAP – TURBULENT AIRFLOW – BREATHY OR APHONIC VOICE. TOO TIGHTLY OPPOSED – EXCESSIVE PRESSURE NEEDED- STRAINED VOICE OR SOMETIMES NO VOICE

18. c) VIBRATORY CAPACITY OF THE VOCAL FOLD. UNDULATION OF MUCOSA FREELY OVER THE UNDERLYING VOCAL LIGAMENT & VOCALIS MUSCLE d) VOCAL CORD SHAPE SHAPE SUCH THAT MEDIAL SURFACES OF TWO VOCAL FOLDS SHOULD BE PARALLEL & SHOULD APPROXIMATE WELL.

19. VOCALIS MUSCLE PALSY – MEDIAL SURFACE OF VOCAL FOLDS CONVEX ; GLOTTIC TRACT TOO CONVERGENT FOR OPTIMAL PHONATION.

20. e) CHANGE IN LENGTH & TENSION CHANGES IN VOCAL CORD LENGTH & TENSION HELP CONTROL THE FREQUENCY OF VIBRATION. LOWER VOCAL RANGE – THYROARYTENOID CONTRACTION TO LOWER THE PITCH. RISING PITCH – CRICOTHYROID CONTRACTION WHICH INCREASE LENGTH & TENSION + STRENTHENING THYROARYTENOID CONTRACTION. FALSETTO (HIGH PITCH) – CRICITHYROID CONTRACTION IN THE ABSENCE OF THYROARYTENOID MUSCLE ACTIVITY.

21. SIZE & PHYSICAL PROPERTIES OF LARYNX GOVERN RANGE OF PITCH. CHILD : SMALLER LARYNX – HIGHER PITCH RANGE. PUBERTY : RAPID INCREASE IN SIZE OF LARYNX - UNSTABLE PITCH CONTROL. INCREASING AGE : LOSS OF ELASTICITY & OSSIFICATION OF THYROID CARTILAGE – INCREASE IN PITCH. YOUNG MEN : LOWEST PITCHES – LONGER & HEAVIER VOCAL FOLDS THAN FEMALE.

22. VOCAL RESONANCE “RESONANCE IS THE PROLONGATION , AMPLIFICATION & FILTERING OF SOUND BY THE INDUCTION OF SYMPATHETIC VIBRATION”. PRIMARY RESONATING STRUCTURE IS THE AIR COLUMN CONTAINED IN THE PHARYNX. RESONATORS SUPRAGLOTTIC PHARYNX ORAL CAVITY NASAL CAVITY PARANASAL SINUSES

23. NASAL RESONANCE IS AFFECTED BY : VELOPHARYNGEAL COMPETENCE NASAL OBSTRUCTION HYPERNASAL SPEECH – CAN OCCUR DUE TO VELOPHARYNGEAL INSUFFICIENCY OR SIGNIFICANT LOWERING OF SOFT PALATE. - HEAR AUDIBLE AIR ESCAPE DURING SPEECH. HYPONASAL SPEECH – SPACE OCCUPYING LESIONS IN NASOPHARYNX.

24. SPEECH / ARTICULATION VOWELS – NO OBSTRUCTION TO THE FLOW OF AIR FROM THE LARYNX TO THE LIPS. CONSONANTS – NEED A DEFINITE OBSTRUCTION BY ONE OR MORE OF THE ARTICULATORS IN THE ORAL TRACT. SEMI VOWELS – SOUNDS SUCH AS ‘W’ & ‘Y’ REGARDED AS CONSONANTS BUT ARTICULATED LIKE VOWELS. CONTINUANTS – ALL VOWELS ARE CONTINUANTS – HAVE LENGTH OF VARYING PERIODS OF TIME.

25. SHORT VOWELS – ‘PIT’ LONG VOWELS – ‘PART’ DIPTHONGS – 2 VOWEL SOUNDS ARE COMBINED – ‘FIRE’ ORGANS OF ARTICULATION – LIPS, TONGUE, TEETH, PALATE. DISTINCTION BETWEEN VOWELS MADE BY : CHANGING THE HEIGHT OF TONGUE. PART OF THE TONGUE THAT’S RAISED. POSITION OF THE LIPS.

26. PLACE OF ARTICULATIONS: BILABIAL CONSONANTS – p, b, m, w – ARTICULATION BETWEEN UPPER & LOWER LIPS. LABIODENTAL CONSONANTS – f, v – TOP TEETH & LOWER LIP ARTICULATION. DENTAL ARTICULATORS – th – TONGUE TIP & TOP TEETH OCCLUSION. ALVEOLAR CONSONANTS – t, d, n, s, z, r, ch , dj – TONGUE TIP TOUCHES THE RIDGE BEHIND THE TEETH.

27. Y – ARTICULATION OF MIDDLE TONGUE WITH HARD PALATE. VELAR CONSONANTS – k, g, ng - BACK OF TONGUE & SOFT PALATE ARTICULATION

28. MANNER OF ARTICULATION (HOW THE AIRFLOW IS OBSTRUCTED) PLOSIVE CONSONANTS – p, b, t, d, k, g. AIR TEMPORARILY COMPRESSED BEHIND THE POINT OF ARTICULATION & THEN RELEASED WITH AN AUDIBLE NOISE CALLED “PLOSION” FRICATIVES – f, z, s. AIR HISSING THROUGH THE CLOSE (BUT NOT COMPLETE) APPROXIMATION OF 2 ARTICULATORS.

29. AFFRICATES – ch , dj (church, judge) COMBINATION OF PLOSION & FRICATIVE ARTICULATION

30. NASAL CONSONANTS - m, n, ng. AIR ESCAPES THROUGH NOSE. OBSTRUCTIVE TONGUE OR LIP ARTICULATION BLOCKS AIR EXIT THROUGH MOUTH & SOFT PALATE. INADEQUATE VELOPHARYNGEAL COMPETENCE – LEADS TO INCOMPLETE NASALISATION. PERMANENT NASOPHARYNGEAL OBSTRUCTION – DENASALISATION OF NASAL CONSONANTS.

31. LATERAL APPROXIMANTS – ‘l’ AIR ESCAPES ALONG THE SIDES OF TONGUE.

32. VOCAL REGISTERS 1) LOFT (OR FALSETTO) – HIGHEST FREQUENCIES KNIFE THIN FREE EDGES OF VOCAL FOLDS ADDUCTED. SUBGLOTTIC AIR PRESSURE. LARYNX RAISED. PHARYNX SHORTENED.

33. 2) MODAL (MIDDLE) – NORMALLY EMPLOYED IN SPEECH / SINGING. VOCAL FOLDS ARE TRIANGULAR. LOWEST NOTE – INFRAHYOID MUSCLES PULL LARYNX DOWN. 3) PULSE / GLOTTAL FRY / VOCAL FRY / CREAKY VOICE : LOWEST VOCAL FREQUENCIES FEATURE OF NORMAL SPEECH.

34. PHASES CLOSING PHASE – VOCAL FOLD BEGINS TO CLOSE FROM INFERIOR MARGIN CLOSED PHASE – MEDIAL EDGES OF VOCAL FOLD IN FULL CONTACT. OPENING PHASE – VF BEGIN TO SEPARATE FROM LOWER MARGIN. SUPERIOR MARGINS IN CONTACT UNTIL THE END. OPEN PHASE – VF SEPERATED (LONGEST PART OF VIBRATORY CYCLE).

35. DEVELOPMENT OF SPEECH 0-2 MONTHS – HEAD TURN TO THE DIRECTION OF SOUND. 2-4 MONTHS – COOING 4-6 MONTHS – SINGLE SYLLABLE BABBLING. 6-9 MONTHS – REPEATED SYLLABLE BABBLING. 12-14 MONTHS - FIRST WORDS 15-18 MONTHS – 5-20 WORDS. 20-24 MONTHS – 2 WORD COMBINATIONS

36. MUSCLE TENSION DYSPHONIA IT IS A CLINICAL CONDITION CHARACTERISED BY “ABNORMAL PRODUCTION OF VOICE & VARIABLE SYMPTOMS OF VOICE DISRUPTION DUE TO EXCESSIVE TENSION & INCOORDINATED ACTIVITY OF INTRINSIC & EXTRINSIC MUSCLES OF LARYNX” PRIMARY – NO IDENTIFIABLE STRUCTURAL OR NEUROLOGICAL ABNORMALITY ASSOCIATED WITH MUSCLE TENSION. SECONDARY – THE HYPERFUNCTIONAL MUSCLE ACTIVITY IS EITHER COEXISTENT AS A COMPENSATORY MECHANISM OF ANY UNDERLYING MUCOSAL DISEASE AND/OR GLOTTIC INSUFFICIENCY

37. THE PATIENT PROFILE INCLUDES: A VOCALLY DEMANDING OCCUPATION. AN ABUSIVE CHILDHOOD. A PERFECTIONIST PERSONALITY A SERIES OF LIFE EVENTS PRIOR TO ONSET. A HISTORY OF FATIGUE A NEUROTIC PERSONALITY

38. ORGANIC PATHOLOGY INCLUDE: - LPR, VOCAL NODULES, POLYPS, CYSTS & REINKES’S EDEMA. TYPES: TYPE 1 MTD - LARYNGEAL ISOMETRIC. TYPE 2 MTD – LATERAL CONTRACTION / HYPERADDUCTION. TYPE 3 MTD – AP CONTRACTION.

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