Laryngeal Muscles

Anatomy of Larynx - Laryngeal Muscles

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.

11. 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.

12. INTRINSIC MUSCLES

13. 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.

14. 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 OVER THE CRICOID.

15. 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.

16. 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.

17. 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.

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

19. 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.