Embryology · Head and neck: pharyngeal arches

First pharyngeal arch (mandibular arch) and the trigeminal nerve !

Embryonic structure

The first arch builds the jaw, the maxilla, two ear ossicles and the chewing muscles. Its nerve is the trigeminal.

Updated 2026-11-01

See it in 3D: Mandible · Maxillae · Zygomatic bones · Temporal bones · Malleus · Incus · Trigeminal nerve (V) · V3 mandibular · V2 maxillary · Trigeminal ganglion · Masseter · Temporalis · Medial pterygoid · Lateral pterygoid · Mylohyoid · Digastric · Maxillary artery

What it is

The first pharyngeal arch, or mandibular arch, splits into a dorsal maxillary process and a ventral mandibular process that holds Meckel's cartilage. It gives the mandible, maxilla, malleus, incus and the muscles of mastication, all supplied by the mandibular division of the trigeminal nerve. Its defects explain Treacher Collins syndrome and the Pierre Robin sequence.

Key facts

End of week 4: the maxillary and mandibular processes surround the stomodeum.
Meckel's cartilage almost entirely disappears; only its dorsal end gives the malleus and incus.
The mandible is not ossified Meckel's cartilage: it forms in membrane around it.

Structure

Maxillary process (dorsal): grows under the eye and forms the side of the midface.
Mandibular process (ventral): holds Meckel's cartilage.
Mesenchyme from caudal midbrain and rhombomere 1–2 neural crest; it is HOX-negative (expresses OTX2).
Nerve: trigeminal; the mandibular division (V3) is motor to its muscles and all three divisions give facial skin sensation.
Artery: the first aortic arch, which regresses and leaves part of the maxillary artery.

What it becomes

Nerve: trigeminal (V3 motor; V1, V2 and V3 sensory to facial skin).
Muscles: masseter, temporalis, medial and lateral pterygoids, mylohyoid, anterior belly of digastric, tensor tympani and tensor veli palatini.
From Meckel's cartilage: malleus, incus, anterior ligament of malleus and sphenomandibular ligament.
By membranous ossification: mandible, maxilla, premaxilla, zygomatic bone and squamous temporal bone.
Also: body (anterior two thirds) of the tongue and its general sensation (lingual nerve, V3); part of the auricle.
Artery: part of the maxillary artery.

Markers

OTX2
Neural crest (R1–R2)
Meckel's cartilage

Clinical notes

Treacher Collins: underdeveloped zygoma, maxilla and mandible, with small ears and conductive hearing loss.
Pierre Robin sequence: small mandible, tongue displaced backwards and cleft palate.
Trigeminal neuralgia and temporomandibular joint disorders involve structures of this arch.
Tensor tympani and tensor veli palatini sit far apart but both keep V3 supply.

Test yourself

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

Which two ossicles come from Meckel's cartilage?

The malleus and the incus.

Which ligament is a remnant of Meckel's cartilage?

The sphenomandibular ligament (and the anterior ligament of the malleus).

Why is tensor veli palatini supplied by the trigeminal nerve?

It comes from the first arch, and muscles keep the nerve of their arch even after migrating.

How does the mandible form in relation to Meckel's cartilage?

By membranous ossification of the mesenchyme around the cartilage, which then almost completely disappears.

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See it in 3D

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

← All of 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 (StatPearls Publishing (NCBI Bookshelf), 2023); Embryology, Face - StatPearls - NCBI Bookshelf (StatPearls Publishing (NCBI Bookshelf), 2024); Langman's Medical Embryology, 13th ed., ch. 17: Head and Neck (Wolters Kluwer, 2015).

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Representative model, for educational purposes only.