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620 SectioN iii RepRoductive ` REPRODUCTIVE—EmbRyOlOgy RepRoductive ` REPRODUCTIVE—EmbRyOlOgy
Pharyngeal arch derivatives
ARCH CARTIlAgE mUSClES NERVES a NOTES
1st pharyngeal Maxillary process Muscles of Mastication CN V chew Pierre Robin sequence—
3
arch Maxilla, zygoMatic (temporalis, Masseter, micrognathia,
bone lateral and Medial glossoptosis, cleft
Mandibular process pterygoids), Mylohyoid, palate, airway
Meckel cartilage anterior belly of digastric, obstruction
Mandible, tensor tympani, anterior Treacher Collins
Malleus and incus, 2/3 of tongue, tensor veli syndrome—autosomal
sphenoMandibular palatini dominant neural
ligament crest dysfunction
2nd pharyngeal Reichert cartilage: Muscles of facial expression, CN VII (facial craniofacial
arch Stapes, Styloid Stapedius, Stylohyoid, expression) abnormalities (eg,
process, leSSer horn platySma, posterior belly smile zygomatic bone
of hyoid, Stylohyoid of digastric and mandibular
ligament hypoplasia),
hearing loss, airway
compromise
3rd pharyngeal Greater horn of hyoid Stylopharyngeus (think CN IX (stylo-
arch of stylopharyngeus pharyngeus)
innervated by swallow stylishly
glossopharyngeal nerve)
4th and 6th Arytenoids, Cricoid, 4th arch: most pharyngeal 4th arch: CN Arches 3 and 4 form
pharyngeal Corniculate, constrictors; cricothyroid, X (superior posterior 1/3 of tongue
arches Cuneiform, Thyroid levator veli palatini laryngeal branch) Arch 5 makes no
(used to sing and 6th arch: all intrinsic simply swallow major developmental
ACCCT) muscles of larynx except 6th arch: CN contributions
cricothyroid X (recurrent/
inferior laryngeal
branch) speak
a Sensory and motor nerves are not pharyngeal arch derivatives. They grow into the arches and are derived from neural crest
(sensory) and neuroectoderm (motor).
When at the restaurant of the golden arches, children tend to first chew (1), then smile (2), then swallow stylishly (3) or
simply swallow (4), and then speak (6).
FAS1_2019_15-Repro.indd 620 11/7/19 5:52 PM
