The document discusses the laryngeal muscles, which are divided into extrinsic and intrinsic muscles. The extrinsic muscles attach the larynx to surrounding structures and move the larynx as a whole, while the intrinsic muscles attach the laryngeal cartilages to each other and are responsible for their individual movements. The intrinsic muscles can be further divided based on their actions of opening/closing the laryngeal inlet, adducting/abducting the vocal cords, and increasing/decreasing vocal cord tension. Specific intrinsic muscles and their functions are described.

1. LARYNGEAL MUSCLES
V.S.RASHMI PRIYEM
ULTRA’S BEST DENTAL SCIENCE COLLEGE,
MADURAI

2. MUSCLES
 TWO TYPES:
 EXTRINSIC AND INTRINSIC

3. EXTRINSIC MUSCLES
 THEY ATTACH THE LARYNX TO THE
SURROUNDING STRUCTURES AND ARE
RESPONSIBLE FOR THE MOVEMENT OF
THE LARYNX AS A WHOLE.
 ALL THE EXTRINSIC MUSCLES ARE
PAIRED.

4. EXTRINSIC MUSCLES
 ALL THE EXTRINSIC MUSCLES ELEVATE
THE LARYNX EXCEPT STERNOTHYROID,
WHICH DEPRESSES THE LARYNX.

5. EXTRINSIC MUSCLES
 INCLUDE:
 1. PALATOPHARYNGEUS.
 2. SALPINGOPHARYNGEUS.
 3. STYLOPHARYNGEUS.
 4. THYROHYOID.
 5. STERNOTHYROID.

6. INTRINSIC MUSCLES
 THEY ATTACH THE LARYNGEAL
CARTILAGES TO EACH OTHER AND ARE
RESPONSIBLE FOR THEIR MOVEMENTS.

7. MAIN FUNCTIONS
 (A) OPEN OR CLOSE THE LARYNGEAL
INLET.
 (B) ADDUCT AND ABDUCT THE VOCAL
CORDS.
 (C) INCREASE OR DECREASE THE
TENSION OF THE VOCAL CORDS.

8. ACCORDING TO THEIR ACTIONS, INTRINSIC
MUSCLES OF THE LARYNX ARE ARRANGED INTO
GROUPS.

9. MUSCLES THAT OPEN OR
CLOSE THE LARYNGEAL INLET
 1. OBLIQUE ARYTENOIDS
 CLOSES THE INLET OF LARYNX.
 2. ARYEPIGLOTTICUS
 CLOSES THE INLET OF LARYNX.
 3. THYROEPIGLOTTICUS
 OPENS THE INLET OF LARYNX.

10. MUSCLES THAT ABDUCT OR
ADDUCT THE VOCAL CORDS
 1. POSTERIOR CRICOARYTENOIDS
 ABDUCT THE VOCAL CORDS.
 2. LATERAL CRICOARYTENOIDS
 ADDUCT THE VOCAL CORDS.
 3. TRANSVERSE ARYTENOID
 ADDUCT THE VOCAL CORDS.

12. MUSCLES THAT INCREASE OR
DECREASE THE TENSION OF
VOCAL CORDS
 1. CRICOTHYROID
 TENSES THE VOCAL CORDS.
 2. VOCALIS
 TENSES THE VOCAL CORDS.
 3. THYROARYTENOID
 RELAXES THE VOCAL CORDS.

13. INTRINSIC MUSCLES

14. CRICOTHYROID MUSCLE
 ONLY MUSCLE OF THE LARYNX, WHICH
LIES ON THE EXTERNAL SURFACE OF THE
LARYNX.
 A SMALL FAN-SHAPED MUSCLE, WHICH
ARISES FROM THE ANTEROLATERAL
ASPECT OF THE CRICOID.
 AFTER ORIGIN, ITS FIBRES PASS
BACKWARDS AND UPWARDS, TO BE
INSERTED INTO THE INFERIOR CORNU
AND ADJACENT LOWER BORDER OF THE
LAMINA OF THE THYROID CARTILAGE.

16. CRICOTHYROID MUSCLE
 SUPPLIED BY EXTERNAL LARYNGEAL
NERVE.
 ITS CONTRACTION MAKES THE THYROID
CARTILAGE TO TILT SLIGHTLY
DOWNWARDS AND FORWARDS AT THE
CRICOTHYROID JOINTS, THEREBY
LENGTHENING AND TENSING THE VOCAL
CORD.
 ALSO HELPS IN ADDUCTION OF VOCAL
CORD.
 THE WHOLE THYROID CARTILAGE CAN
MOVE DOWNWARDS AND FORWARDS

17. VOCALIS MUSCLE
 DETACHED MEDIAL PART OF THE
THYROARYTENOID AND LIES WITHIN THE
VOCAL FOLD JUST LATERAL AND CRANIAL
TO THE VOCAL LIGAMENT.
 ARISES FROM THE THYROID ANGLE AND
ANTERIOR PART OF VOCAL LIGAMENT
AND INSERTED INTO THE LATERAL
SURFACE OF THE VOCAL PROCESS.

19. VOCALIS MUSCLE
 ON ITS CONTRACTION THE ANTERIOR
PART OF VOCAL LIGAMENT TENSES
WHEREAS ITS POSTERIOR PART IS
RELAXED.
 SUPPLIED BY THE RECURRENT
LARYNGEAL NERVE.
 THE SEGMENTAL TENSION OF VOCAL
LIGAMENT HELPS IN THE MODULATION OF
VOICE LIKE THE FINGERS OF A VIOLINIST.

20. POSTERIOR
CRICOARYTENOID
 A TRIANGULAR MUSCLE, WHICH ARISES
FROM THE POSTERIOR SURFACE OF THE
CRICOID LAMINA LATERAL TO ITS MEDIAN
RIDGE.
 AFTER ORIGIN, THE FIBRES PASS
UPWARDS AND LATERALLY TO BE
INSERTED INTO THE BACK OF THE
MUSCULAR PROCESS OF THE
ARYTENOID.

21. POSTERIOR
CRICOARYTENOID
 SUPPLIED BY RECURRENT LARYNGEAL
NERVE.
 POSTERIOR CRICOARYTENOID ABDUCTS
THE VOCAL CORDS.

22. NERVE SUPPLY
 ALL THE INTRINSIC MUSCLES OF THE
LARYNX ARE SUPPLIED BY RECURRENT
LARYNGEAL NERVE.
 EXCEPT CRICOTHYROID, WHICH IS
SUPPLIED BY THE EXTERNAL LARYNGEAL
NERVE.