In this article we covered-
• Larynx Intrinsic muscles (Total 9 muscles)
• Vagus nerve (Superior and inferior/recurrent laryngeal nerve)
• Pharyngeal arch (4th and 6th arch)
Larynx muscles (Intrinsic muscles)
● Development– All Intrinsic Muscles of the Larynx are developed from the 6th pharyngeal arch except the Cricothyroid muscle (this is developed from the 4th pharyngeal arch).
● Name– Muscles of the larynx (Intrinsic muscles):
NOTE: Larynx Intrinsic muscles are named on the basis of their attachment.
1. Cricothyroid muscle; It is present between the cricoid cartilage and thyroid cartilage.
2. Thyroepiglottic muscle; is present between the thyroid cartilage and epiglottis.
3. Thyroarytenoid muscle; It is present between the thyroid cartilage and arytenoid cartilage.
4. Aryepiglottic muscle; is present between arytenoid cartilage and epiglottis.
5. Oblique arytenoid muscle (Paired Muscle); It is oblique present between two (Rt. and Lt.) arytenoid cartilage.
6. Transverse arytenoid muscle (Unpaired Muscle); It is transverse present between two (Rt. and Lt.) arytenoid cartilage
7. Lateral or Anterior cricoarytenoid muscles (Paired Muscle); It is present between the cricoid cartilage and arytenoid cartilage.
8. Posterior cricoarytenoid muscles (Paired Muscle); It is present between cricoid cartilage and arytenoid cartilage.
+ This muscle also called the safety muscle of the larynx (Region: due to their action; Abduction of vocal cord)
9. Vocalis muscle
● Nerve supply– All intrinsic muscles of the larynx are supplied by the recurrent laryngeal nerve (Vagus nerve branch) except the Cricothyroid muscle (This is supplied by the external laryngeal nerve).
(Here we will discuss only two branches of the vagus nerve that supply intrinsic muscles of the larynx)
1. Superior laryngeal nerve-
• This is the nerve of the 4th pharyngeal arch.
• Divide into external (Motor branch) and Internal (Sensory branch) laryngeal nerve.
• This nerve(External laryngeal nerve) supplies to the cricothyroid muscle.
2. Inferior/recurrent laryngeal nerve (RLN)-
• This is the nerve of the 6th pharyngeal arch.
• This nerve supplies to the muscles of the larynx (2 to 9; see above).