[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Embryology](https://durgical.com/en/embryology/) › [Head and neck: pharyngeal arches](https://durgical.com/en/embryology/#a-head_neck) › Fourth and sixth pharyngeal arches: the larynx and the vagus nerve

[Embryology](https://durgical.com/en/embryology/) · [Head and neck: pharyngeal arches](https://durgical.com/en/embryology/#a-head_neck)

# Fourth and sixth pharyngeal arches: the larynx and the vagus nerve

- Embryonic structure

Arches 4 and 6 build the laryngeal cartilages and muscles. The vagus supplies them through two branches: superior and recurrent laryngeal.

Updated 2026-11-01

**See it in 3D:** [Thyroid cartilage](https://durgical.com/en/anatomy/thyroid-cartilage/) · [Cricoid cartilage](https://durgical.com/en/anatomy/cricoid-cartilage/) · [Arytenoid cartilages](https://durgical.com/en/anatomy/arytenoid-cartilage/) · [Corniculate cartilages](https://durgical.com/en/anatomy/corniculate-cartilage/) · [Vagus nerve](https://durgical.com/en/anatomy/vagus-nerve/) · [Superior laryngeal nerve](https://durgical.com/en/anatomy/superior-laryngeal-nerve/) · [Recurrent laryngeal nerves](https://durgical.com/en/anatomy/recurrent-laryngeal-nerve/) · [Cricothyroid](https://durgical.com/en/anatomy/oblique-part-of-cricothyroid-muscle/) · [Posterior cricoarytenoid](https://durgical.com/en/anatomy/musculus-cricoarytenoideus-posterior/) · [Lateral cricoarytenoid](https://durgical.com/en/anatomy/lateral-cricoarytenoid-muscle/) · [Thyroarytenoid](https://durgical.com/en/anatomy/musculus-thyreoarytenoideus/) · [Arytenoid muscles](https://durgical.com/en/anatomy/transverse-arytenoid-muscle/) · [Vocal folds](https://durgical.com/en/anatomy/vocal-fold/) · [Pharyngeal constrictors](https://durgical.com/en/anatomy/superior-pharyngeal-constrictor/) · [Soft palate](https://durgical.com/en/anatomy/soft-palate/) · [Aortic arch](https://durgical.com/en/anatomy/aortic-arch/) · [Subclavian artery](https://durgical.com/en/anatomy/right-subclavian-artery/) · [Pulmonary arteries](https://durgical.com/en/anatomy/right-pulmonary-artery/)

## Key points

- 4th arch: superior laryngeal, cricothyroid, constrictors, levator veli palatini.
- 6th arch: recurrent laryngeal, all intrinsic muscles except cricothyroid.
- Laryngeal cartilages: from fused arches 4 and 6.
- 4th aortic arch: aortic arch (L) and proximal right subclavian (R).
- 6th aortic arch: pulmonary arteries and ductus arteriosus (L).

## What it is

The fourth and sixth pharyngeal arches fuse to form the laryngeal cartilages, and their muscles are supplied by the vagus: the 4th through the superior laryngeal nerve and the 6th through the recurrent laryngeal nerve. Their aortic arches give the aortic arch, the right subclavian, the pulmonary arteries and the ductus arteriosus. That explains why the two recurrent nerves take different paths and why they are injured in thyroid or chest surgery.

## Key facts

- On the right the dorsal 6th arch disappears and the recurrent nerve moves up to hook under the subclavian (4th arch).
- On the left the ductus arteriosus persists and the recurrent nerve stays hooked under the aortic arch.
- The fifth arch is rudimentary and leaves no derivatives.

## Structure

- Mesenchyme from rhombomere 6–7 neural crest, with paralogue group 3 HOX genes.
- Nerve of the 4th arch: superior laryngeal branch of the vagus.
- Nerve of the 6th arch: recurrent laryngeal branch of the vagus.
- The cartilages of both arches fuse; textbooks assign them together.

## What it becomes

- 4th arch, muscles: cricothyroid, levator veli palatini and the pharyngeal constrictors (superior laryngeal and pharyngeal branches of the vagus).
- 6th arch, muscles: all intrinsic laryngeal muscles except cricothyroid (cricoarytenoids, thyroarytenoid, arytenoids).
- Skeleton (4th and 6th): thyroid, cricoid, arytenoid, corniculate and cuneiform cartilages.
- 4th aortic arch: on the left, part of the aortic arch; on the right, the proximal right subclavian artery.
- 6th aortic arch: proximal pulmonary arteries; on the left, its dorsal part forms the ductus arteriosus (later the ligamentum arteriosum).

## Markers

- HOXA3
- HOXB3
- Neural crest (R6–R7)

## Clinical notes

- Recurrent nerve injury (thyroidectomy, lung apex or mediastinal tumours, aortic arch aneurysm): hoarseness from vocal fold paralysis.
- The left recurrent nerve, longer and running in the chest, is more often hit by mediastinal disease.
- Superior laryngeal nerve injury: monotone voice without high notes, from loss of cricothyroid.
- Errors in regression of arches 4 and 6 cause vascular rings, aberrant right subclavian artery and patent ductus arteriosus.

## Memory aid

The fourth sings high (cricothyroid, high notes, superior laryngeal); the sixth opens and shuts the door (vocal folds, recurrent).

## Test yourself

Think of the answer, then tap the question to see it.

## Which nerve supplies the muscles of the fourth pharyngeal arch?

The superior laryngeal branch of the vagus.

## Why does the left recurrent laryngeal nerve hook under the aortic arch and the right one under the subclavian?

On the left the dorsal 6th arch persists (ductus arteriosus) and holds it; on the right that segment disappears and the nerve moves up to the subclavian, a 4th-arch vessel.

## Which intrinsic laryngeal muscle comes from the fourth arch?

Cricothyroid.

## What does the left fourth aortic arch become?

Part of the arch of the aorta.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/embryology/fourth-and-sixth-pharyngeal-arches-the-larynx-and-the-vagus-nerve/)

## See it in 3D

The structures of Durgical's 3D anatomy where it is found.

- [Thyroid cartilage](https://durgical.com/en/anatomy/thyroid-cartilage/)
- [Cricoid cartilage](https://durgical.com/en/anatomy/cricoid-cartilage/)
- [Arytenoid cartilages](https://durgical.com/en/anatomy/arytenoid-cartilage/)
- [Corniculate cartilages](https://durgical.com/en/anatomy/corniculate-cartilage/)
- [Vagus nerve](https://durgical.com/en/anatomy/vagus-nerve/)
- [Superior laryngeal nerve](https://durgical.com/en/anatomy/superior-laryngeal-nerve/)
- [Recurrent laryngeal nerves](https://durgical.com/en/anatomy/recurrent-laryngeal-nerve/)
- [Cricothyroid](https://durgical.com/en/anatomy/oblique-part-of-cricothyroid-muscle/)
- [Posterior cricoarytenoid](https://durgical.com/en/anatomy/musculus-cricoarytenoideus-posterior/)
- [Lateral cricoarytenoid](https://durgical.com/en/anatomy/lateral-cricoarytenoid-muscle/)
- [Thyroarytenoid](https://durgical.com/en/anatomy/musculus-thyreoarytenoideus/)
- [Arytenoid muscles](https://durgical.com/en/anatomy/transverse-arytenoid-muscle/)
- [Vocal folds](https://durgical.com/en/anatomy/vocal-fold/)
- [Pharyngeal constrictors](https://durgical.com/en/anatomy/superior-pharyngeal-constrictor/)
- [Soft palate](https://durgical.com/en/anatomy/soft-palate/)
- [Aortic arch](https://durgical.com/en/anatomy/aortic-arch/)
- [Subclavian artery](https://durgical.com/en/anatomy/right-subclavian-artery/)
- [Pulmonary arteries](https://durgical.com/en/anatomy/right-pulmonary-artery/)

## Related

- [Pharyngeal arches: nerve, muscles, skeleton and artery (the table)](https://durgical.com/en/embryology/pharyngeal-arches-nerve-muscles-skeleton-and-artery/)
- [The pharyngeal apparatus: arches, pouches, clefts and membranes](https://durgical.com/en/embryology/the-pharyngeal-apparatus-arches-pouches-clefts-and-membranes/)
- [Aortic arch arteries and their derivatives](https://durgical.com/en/embryology/aortic-arch-arteries-and-their-derivatives/)
- [Vascular rings and aberrant right subclavian artery](https://durgical.com/en/embryology/vascular-rings-and-aberrant-right-subclavian-artery/)
- [Patent ductus arteriosus](https://durgical.com/en/embryology/patent-ductus-arteriosus/)
- [Lung development: the five stages](https://durgical.com/en/embryology/lung-development-the-five-stages/)
- [Tongue: development and innervation](https://durgical.com/en/embryology/tongue-development-and-innervation/)
- [Third pharyngeal arch and the glossopharyngeal nerve](https://durgical.com/en/embryology/third-pharyngeal-arch-and-the-glossopharyngeal-nerve/)

## Related conditions

- [Patent ductus arteriosus](https://durgical.com/en/conditions/patent-ductus-arteriosus/)

[← All of embryology](https://durgical.com/en/embryology/)

Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given.

Sources: [Embryology, Branchial Arches - StatPearls - NCBI Bookshelf](https://www.ncbi.nlm.nih.gov/books/NBK538487/) (StatPearls Publishing (NCBI Bookshelf), 2023); [Embryology, Aortic Arch - StatPearls - NCBI Bookshelf](https://www.ncbi.nlm.nih.gov/books/NBK553173/) (StatPearls Publishing (NCBI Bookshelf), 2023); Langman's Medical Embryology, 13th ed., ch. 17: Head and Neck (Wolters Kluwer, 2015).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/embryology/fourth-and-sixth-pharyngeal-arches-the-larynx-and-the-vagus-nerve/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/embryology/fourth-and-sixth-pharyngeal-arches-the-larynx-and-the-vagus-nerve/