Pharynx and Craniofacial Development

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Gastrointestinal development | Main Anatomy Index | Musculoskeletal development

Last updated 30 March 2006

This page was contributed by David Boshell

Pharynx and Craniofacial Development

Pharyngeal arches

  1. An arch cartilage
  2. An arch artery
  3. A paraxial mesoderm component (muscle anlage)
  4. An arch-specific cranial nerve.

Pharyngeal arch cartilages

  1. The maxillary swelling, containing the palatopterygoquadrate bar cartilage, giving rise to the greater wing of sphenoid and the incus
  2. The mandibular swelling, containing Meckel’s cartilage, giving rise to the malleus and the fibrous core of the mandible

Pharyngeal arch arteries

Pharyngeal arch muscles

Pharyngeal arch innervation

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Derivatives of the Pharyngeal Arches and their tissues of origin

Arch

Arch Artery

Skeletal Elements

Muscles (SVE)

Cranial Nerve

1

Terminal branch of maxillary artery Derived from arch cartilages (originating from neural crest):
  • From maxillary cartilage: alisphenoid, incus
  • From mandibular (Meckel’s) cartilage: malleus

Derived by direct ossification from arch dermal mesenchyme: maxilla, zygomatic, squamous part of temporal bone, mandible

Muscles of mastication (temporalis, masseter, pterygoids), myelohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini (originate from cranial somitomere 4) Maxillary (V2), mandibular (V3) divisions of trigeminal nerve (V), for each respective swelling

2

Stapedial artery (embryonic), corticotympanic artery (adult) Stapes, styloid process, stylohyoid ligament, lesser horns and upper rim of hyoid (derived from the 2nd arch [Reichert’s] cartilage; originate from neural crest) Muscles of facial expression (orbicularis oculi, risorius, platysma, auricularis, fronto-occipitalis, buccinator), posterior belly of digastric, stylohyoid, stapedius (originate from cranial somitomere 6) Facial nerve (VII)

3

Common carotid artery, root of internal carotid Lower rim and greater horns of hyoid (derived from the 3rd arch cartilage; originate from neural crest) Stylopharyngeus (originates from cranial somitomere 7) Glosso-pharyngeal nerve (IX)

4

Arch of aorta, Right of subclavian artery, original sprouts of pulmonary arteries Laryngeal cartilages (from 4th arch cartilage, originate from lateral plate mesoderm) Constrictors of pharynx, cricothyroid, levator veli palatini (originate from occipital somites 2-4) Superior laryngeal branch of vagus nerve (X)

6

Ductus arteriosus, roots of definitive pulmonary arteries Laryngeal cartilages (derived from the 6th arch cartilage; originate from lateral plate mesoderm) Intrinsic muscles of larynx (originate from occipital somites 1-2) Recurrent laryngeal branch of vagus nerve (X)

Larson, W. Human Embryology 2nd ed., Churchill Livingstone, 1997, p357: Table 12-1.

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Pharyngeal Clefts

Pharyngeal Pouches

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Cranial Development

  1. The chondrocranium, which forms from 3 parasagittal cartilages and 3 sensory capsules via endochondral ossification
  2. The membrane (dermal) bones, ossifying directly from mesenchyme of the skin
  3. The branchial skeleton of the pharyngeal arches, forming via endochondral ossification.

Parasagittal cartilages

Embryological cartilages

Adult bones

Prechordal

Part of ethmoid bone

Hypophyseal

Body of sphenoid

Parachordal

Base of occipital bone

 

Primitive sensory capsules

Capsule

Adult bones

Olfactory

The nasal turbines, portions of ethmoid and nasal bones

Optic

Lesser wings of sphenoid

Otic

Periotic (petromastoid) portion of temporal bone

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Facial development

Paranasal sinuses

Sinus

Description

Maxillary sinuses

Appear in 3rd month, enlarge throughout childhood

Ethmoid sinuses

Appear in 5th month, enlarge until puberty

Sphenoid sinuses

Extensions of ethmoid sinuses

Frontal sinuses

Appear at 5-6 years, grow throughout adolescence

 

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Development of the tongue, thyroid and salivary glands

Innervation of the tongue

.

Anterior third

Posterior third

Sensory

Mandibular n. (CN V3),

lingual branch

Glossopharyngeal n.

(CN IX)

Taste (SVA)

Facial n. (CN VII),

chorda tympani branch

Motor

Hypoglossal n. (CN XII),

all muscles except palatoglossus (pharyngeal plexus)

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Michael Tam (c) 1999