Head Development

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Introduction

Fetal head (week 12)

The head and neck is not really a "system", but structurally quite different in origin from the body. The head and neck are one of the most complicated structures that the embryo forms, with special intermediate structures (the pharyngeal arch) and contributions from all 3 embryonic layers (ectoderm, mesoderm, endoderm), and significantly, a major contribution from the neural crest. Neural crest contributes jaw skeletal elements,, connective tissues and tendons. The associated muscles derive mainly from cranial mesoderm. These components though will form different structures dependent upon which arch they are within. The cavity within the pharyngeal arches forms the pharynx.


The pharynx contributes to 2 endocrine organs, in the roof the pituitary (hypophysis) and the floor the thyroid. The thyroid gland, being one of the first endocrine organs to be formed, has an important role in embryonic development. The pharynx floor of all arches also contribute to the formation of the tongue.


Because the head contains many different structures also review notes on: skull, sensory (placode, vision, hearing, smell, taste), respiratory (pharynx), integumentary(tooth, hair) and endocrine (pituitary, thyroid, parathyroid, thymus).


Head Links: Introduction | Medicine Lecture | Medicine Lab | Science Lecture | Lecture Movie | Science Lab | pharyngeal arch | Craniofacial Seminar | mouth | palate | tongue | placode | skull | neural crest | Head and Face Movies | head abnormalities | Category:Head
Historic Head Embryology  
1910 Skull | 1910 Skull Images | 1912 Nasolacrimal Duct | 1921 Human Brain Vascular | 1923 Head Subcutaneous Plexus | 1919 21mm Embryo Skull | 1920 Human Embryo Head Size | 1921 43 mm Fetal Skull | Historic Disclaimer

Some Recent Findings

  • Review - MR Imaging of the Fetal Face[1] "The human face is a complex anatomic structure with an equally complex embryologic development. Derangement of the developmental process can result in various structural anomalies, which range from a mainly cosmetic deformity, such as cleft lip, to potentially life-threatening conditions such as arhinia. These anomalies (a) can occur as isolated anomalies; (b) can be associated with intracranial, spinal, or dental anomalies; or (c) can be a part of various syndromes, thus serving as diagnostic clues in such cases. Proper evaluation of fetal facial deformities can help in prognostication, family counseling, and prenatal or early postnatal intervention. Ultrasonography (US) is the first line of investigation in these cases. However, when US does not allow complete evaluation of these anomalies owing to its inherent limitations, magnetic resonance (MR) imaging allows comprehensive evaluation of the anomaly itself and also evaluation of various associations and the treatment approach. The embryology of the fetal facial structures is considered with regard to the MR imaging technique and the MR imaging anatomy. The MR imaging features of various structural anomalies are described and classified into six groups, namely, orofacial clefts, orbital anomalies, nasal anomalies, facial masses, external ear anomalies, and abnormal face shape or profile." Magnetic Resonance Imaging
  • Branchial anomalies in children: A report of 105 surgical cases[2] "Branchial anomalies (BAs) account for 20% of all congenital masses in children. We sought to review the incidence of involvement of individual anomalies, diagnostic methods, surgical treatment, and complications of BAs in children. ...A total of 33 (31.4%) cases presented with first BAs, 13 (12.4%) presented with second BAs, and 59 (56.2%) presented with third and fourth BAs, including 6 cases of congenital lower neck cutaneous fistula."
  • Developmental and evolutionary origins of the pharyngeal apparatus[3] "The vertebrate pharyngeal apparatus, serving the dual functions of feeding and respiration, has its embryonic origin in a series of bulges found on the lateral surface of the head, the pharyngeal arches. Developmental studies have been able to discern how these structures are constructed and this has opened the way for an analysis of how the pharyngeal apparatus was assembled and modified during evolution. For many years, the role of the neural crest in organizing pharyngeal development was emphasized and, as this was believed to be a uniquely vertebrate cell type, it was suggested that the development of the pharyngeal apparatus of vertebrates was distinct from that of other chordates."
  • hand2 and Dlx genes specify dorsal, intermediate and ventral domains within zebrafish pharyngeal arches.[4] "The ventrally expressed secreted polypeptide endothelin1 (Edn1) patterns the skeleton derived from the first two pharyngeal arches into dorsal, intermediate and ventral domains. ...Collectively, our work indicates that the expression and function of hand2 and Dlx genes specify major patterning domains along the dorsoventral axis of zebrafish pharyngeal arches."
More recent papers  
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This table shows an automated computer PubMed search using the listed sub-heading term.

  • Therefore the list of references do not reflect any editorial selection of material based on content or relevance.
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Search term: Head Development

Kasper Jacobsen Kyng, Anders Valdemar Edhager, Tine Brink Henriksen, Christer Zøylner Swan, Niels Gregersen, Johan Palmfeldt Biomarker Discovery by Mass Spectrometry in Cerebrospinal Fluid and Plasma after Global Hypoxia-Ischemia in Newborn Piglets. Neonatology: 2018, 114(4);307-314 PubMed 30025402

Naoki Kiyota, Yukihiro Shiga, Kohei Ichinohasama, Masayuki Yasuda, Naoko Aizawa, Kazuko Omodaka, Naoto Honda, Hiroshi Kunikata, Toru Nakazawa The Impact of Intraocular Pressure Elevation on Optic Nerve Head and Choroidal Blood Flow. Invest. Ophthalmol. Vis. Sci.: 2018, 59(8);3488-3496 PubMed 30025080

Toby M Enniss, Khaled Basiouny, Brian Brewer, Nikolay Bugaev, Julius Cheng, Omar K Danner, Thomas Duncan, Shannon Foster, Gregory Hawryluk, Hee Soo Jung, Felix Lui, Rishi Rattan, Pina Violano, Marie Crandall Primary prevention of contact sports-related concussions in amateur athletes: a systematic review from the Eastern Association for the Surgery of Trauma. Trauma Surg Acute Care Open: 2018, 3(1);e000153 PubMed 30023433

Qian-Qian Li, Qian Liu, Jun-Mei Yan, Xian Wang [Effects of different feeding patterns on the growth and development of infants with very/extremely low birth weight]. Zhongguo Dang Dai Er Ke Za Zhi: 2018, 20(7);572-577 PubMed 30022761

Linnea Haeggblom, Ramona Gabriela Ursu, Leila Mirzaie, Tove Attoff, Caroline Gahm, Lalle Hammarstedt Nordenvall, Anders Näsman No evidence for human papillomavirus having a causal role in salivary gland tumors. Diagn Pathol: 2018, 13(1);44 PubMed 30021645

Textbooks

Pharyngeal arch cartilages.jpg
  • The Developing Human: Clinically Oriented Embryology (8th Edition) by Keith L. Moore and T.V.N Persaud - Moore & Persaud Chapter Chapter 10 The Pharyngeal Apparatus pp201 - 240.
  • Larsen’s Human Embryology by GC. Schoenwolf, SB. Bleyl, PR. Brauer and PH. Francis-West - Chapter 12 Development of the Head, the Neck, the Eyes, and the Ears pp349 - 418.
Head Movies  
Face 001 icon.jpg
 ‎‎Face Development
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Palate 001 icon.jpg
 ‎‎Palate (oral view)
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Palate 002 icon.jpg
 ‎‎Palate (front view)
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Tongue 001 icon.jpg
 ‎‎Tongue
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Postnatal human mandible growth icon.jpg
 ‎‎Mandible Growth
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Endoderm 002 icon.jpg
 ‎‎Endoderm
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Stage16-18 face 02.jpg
 ‎‎Face Stage 16-18
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Stage15to22 head icon.jpg
 ‎‎Head Stage 15-22
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Stage23 MRI S01 icon.jpg
 ‎‎Sagittal Head
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Fetal week 10 palate icon.jpg
 ‎‎Fetal Palate
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Mouse cranial neural crest migration 01.jpg
 ‎‎Cranial Neural Crest
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Mouse face microCT icon.jpg
 ‎‎Mouse Face
Page | Play
UNSW Students
Mark Hill icon.jpg You have access the following online Embryology textbooks through the UNSW Library.
The Developing Human, 8th edn.jpg Moore, K.L. & Persuad, T.V.N. (2008). The Developing Human: clinically oriented embryology (8th ed.). Philadelphia: Saunders.

The following chapter links only work with a UNSW connection.

Objectives

  • List the main structures derived from the pharyngeal arches, pouches and clefts.
  • Know the stages and structures involved in the development of the face.
  • Predict the results of abnormal development of the face and palate.
  • Briefly summarise the development of the tongue.

The Pharynx

Head arches cartoon.jpg Stage13 B2 excerpt.gif Pharynx cartoon.jpg

The cavity within the pharyngeal arches forms the pharynx.

The pharynx contributes to 2 endocrine organs, in the roof the [endocrine7.htm pituitary] (hypophysis) and the floor the thyroid. The thyroid gland being one of the first endocrine organs to be formed has an important role in embryonic development. The pharynx floor of all arches also contribute to the formation of the [head6.htm tongue].

Pharyngeal Arch Components

Human embryo Stage 13 oral cavity floor
Human embryo pharyngeal arches (Stage 13 oral cavity floor)

Major features to identify for each: arch, pouch, groove and membrane. Contribute to the formation of head and neck and in the human appear at the 4th week. The first arch contributes the majority of upper and lower jaw structures.

Early Face and Pharynx

  • Pharynx - begins at the buccopharyngeal membrane (oral membrane), apposition of ectoderm with endoderm (no mesoderm between)


Pharyngeal Arch Development

Pharyngeal arch structure cartoon.gifStage13 pharyngeal arch excerpts.gif

  • branchial arch (Gk. branchia= gill)
  • arch consists of all 3 trilaminar embryo layers
  • ectoderm- outside
  • mesoderm- core of mesenchyme
  • endoderm- inside

Neural Crest

  • Mesenchyme invaded by neural crest generating connective tissue components
  • cartilage, bone, ligaments
  • arises from midbrain and hindbrain region

Arch Features

Each arch contains: artery, cartilage, nerve, muscular component

Arches and Phanynx Form the face, tongue, lips, jaws, palate, pharynx and neck cranial nerves, sense organ components, glands

  • Humans have 5 arches - 1, 2, 3, 4, 6 (Arch 5 does not form or regresses rapidly)
  • from in rostro-caudal sequence, Arch 1 to 6 from week 4 onwards
  • arch 1 and 2 appear at time of closure of cranial neuropore
  • Face - mainly arch 1 and 2
  • Neck components - arch 3 and 4 (arch 4 and 6 fuse)

Arch Features

    • arch
    • groove
      • externally separates each arch
        • also called a cleft
      • only first pair persist as external auditory meatus
    • pouch
      • internally separates each arch
      • pockets from the pharynx
    • membrane
      • ectoderm and endoderm contact regions
      • only first pair persist as tympanic membrane
  • Pharyngeal Arch 1 (Mandibular Arch) has 2 prominances
    • smaller upper- maxillary forms maxilla, zygomatic bone and squamous part of temporal
    • larger lower- mandibular, forms mandible
  • Pharyngeal Arch 2 (Hyoid Arch)
    • forms most of hyoid bone
  • Arch 3 and 4
    • neck structures

Arch Arteries

  • Arch 1 - mainly lost, form part of maxillary artery
  • Arch 2 - stapedial arteries
  • Arch 3 - common carotid arteries, internal carotid arteries
  • Arch 4 - left forms part of aortic arch, right forms part right subclavian artery
  • Arch 6 - left forms part of left pulmonary artery , right forms part of right pulmonary artery


placental vein -> liver -> heart -> truncus arteriosus -> aortic sac -> arch arteries -> dorsal aorta -> placental artery

Congdon1922-34.jpg

Human embryo (5mm, lateral view) showing pulmonary arteries

Arch 5 Artery?
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There has been ongoing controversy as to whether the fifth arch artery, that forms in fish, ever develops in birds and mammals. A recent study in mouse and human embryos identified the presence of an extra vessel presence in a single Carnegie Stage 14 human embryo.[5]


Arch Cartilage

Meckel's cartilage, first pharyngeal arch
Pharyngeal arch cartilages
  • Arch 1 - Meckel's cartilage, horseshoe shaped
    • dorsal ends form malleus and incus
    • midpart forms ligaments (ant. malleus, sphenomandibular)
    • ventral part forms mandible template
  • Arch 2 - Reichert's cartilage
    • dorsal ends form stapes and Temporal bone styloid process
    • ventral part ossifies to form hyoid bone components
    • lesser cornu and superior body
  • Arch 3- forms greater cornu and inferior part of hyoid
  • Arch 4&6- form laryngeal cartilages, except epiglottis (from hypobranchial eminence)

Arch Muscle

  • Arch 1 - muscles of mastication, mylohyoid, tensor tympanic, ant. belly digastric
  • Arch 2 - muscles of facial expression, stapedius, stylohyoid, post. belly digastric
  • Arch 3 - stylopharyngeus
  • Arch 4&6 - crycothyroid, pharynx constrictors, larynx muscles, oesophagus (st. muscle)

Head and heart muscle cartoon.jpg

Head and Heart Muscle[6] On the left side of the body (right part of figure) the facial expression muscles have been removed to show the masticatory muscles.

Arch Nerve

trigeminal
  • Arch 1 - CN V trigeminal, caudal 2/3 maxillary and mandibular, cranial 1/3 sensory nerve of head and neck, mastication motor
  • Arch 2 - CN VII facial
  • Arch 3 - CN IX glossopharyngeal
  • Arch 4&6 - CN X vagus, arch 4- superior laryngeal, arch 6- recurrent laryngeal

Arch Pouches

  • Arch 1 - elongates to form tubotympanic recess, tympanic cavity, mastoid antrum, eustachian tube
  • Arch 2 - forms tonsillar sinus, mostly oblierated by palatine tonsil
  • Arch 3 - forms inferior parathyroid and thymus
  • Arch 4 - forms superior parathyroid, parafollicular cells of Thyroid

Thyroid Gland

  • not a pouch structure
  • first endocrine organ to develop day 24
  • from floor of pharynx
  • descends thyroglossal duct (which closes)
  • upper end at foramen cecum

Anterior Pituitary

Pituitary
  • not a pouch structure
  • boundary epitheilal ectoderm in the roof of the pharynx
  • forms a pocket (Rathke's pouch) that comes into contact with the ectoderm of developing brain.
    • Rathke's pouch is named after German embryologist and anatomist Martin Heinrich Rathke (1793 — 1860).

Face Development

Stage16-18 face animation.gif

Begins week 4 centered around stomodeum, external depression at oral membrane

5 initial primordia from neural crest mesenchyme

  • single frontonasal prominence (FNP) - forms forehead, nose dorsum and apex
  • nasal placodes develop later bilateral, pushed medially
  • paired maxillary prominences - form upper cheek and upper lip
  • paired mandibular prominences - lower cheek, chin and lower lip

Frontonasal Process

Frontonasal prominence (Week 7, 44 - 48 days, CRL 13 - 17 mm)

The frontonasal process (FNP) forms the majority of the superior part of the early face primordia. It later fuses with the maxillary component of the first pharyngeal arch to form the upper jaw. Failure of this fusion event during the embryonic period leads to cleft lip. Under the surface ectoderm the process mesenchyme consists of two cell populations; neural crest cells, forming the connective tissues; and the mesoderm forming the endothelium of the vascular network.

A chicken developmental model study has identified a specific surface region, the Frontonasal Ectodermal Zone (FEZ), initially induced by bone morphogenetic proteins that appears to regulate the future growth and patterning of the frontonasal process. The specific frontonasal ectodermal zone was located in the frontonasal process ectoderm flanking a boundary between Sonic hedgehog (Shh) and Fibroblast growth factor 8 (Fgf8) expression domains.[7]

Head/Skull

  • chondrocranium forms base of skull
  • in lower vertebrates encases brain
  • cranial vault
  • calveria
  • facial skeleton
  • pharyngeal arches
Adult Skull MRI Links: Skull Development - MRI
Adult Skull Movie 1 icon.jpg
 ‎‎Viscerocranium
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Adult Skull Movie 2 icon.jpg
 ‎‎Temporal Bones
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Adult Skull Movie 3 icon.jpg
 ‎‎Occipital - Frontal
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Adult Skull Movie 4 icon.jpg
 ‎‎Parietal-Zygomatic
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Sensory Placodes

Sensory placodes (week 5)
  • During week 4 a series of thickened surface ectodermal patches form in pairs rostro-caudally in the head region.
  • Recent research suggests that all sensory placodes may arise from common panplacodal primordium origin around the neural plate, and then differentiate to eventually have different developmental fates.
  • These sensory placodes will later contribute key components of each of our special senses (vision, hearing and smell). Other species have a number of additional placodes which form other sensory structures (fish, lateral line receptor). Note that their initial postion on the developing head is significantly different to their final position in the future sensory system

Otic placode

in the stage 13/14 embryo (shown below) the otic placode has sunk from the surface ectoderm to form a hollow epithelial ball, the otocyst, which now lies beneath the surface surrounded by mesenchyme (mesoderm). The epithelia of this ball varies in thickness and has begun to distort, it will eventually form the inner ear membranous labyrinth.

Lens placode

lies on the surface, adjacent to the outpocketing of the nervous system (which will for the retina) and will form the lens.

Links: Lens Development

Nasal placode

has 2 components (medial and lateral) and will form the nose olfactory epithelium.


Links: Smell Development | Placodes

Head Growth

Developing skull Computed Tomography (CT) image showing normal sutures.
  • continues postnatally - fontanelle allow head distortion on birth and early growth
  • bone plates remain unfused to allow growth, puberty growth of face

Fetal head growth circumference graph01.jpg

Fetal head growth (circumference)


Skull Overview

Chondrocranium - formed from paraxial mesoderm

  • cranial end of vertebral column
  • modified vertebral elements
  • occipital and cervical sclerotome
  • bone preformed in cartilage (endochondrial ossification)

Cranial Vault and Facial Skeleton - formed from neural crest

  • muscle is paraxial mesoderm
  • somitomeres and occipital somites

Calveria - bone has no cartilage (direct ossification of mesenchyme)

  • bones do not fuse, fibrous sutures 1. allow distortion to pass through birth canal 2. allow growth of the brain
  • 6 fontanelles, posterior closes at 3 months, anterior closes at 18 months


Links: Skull Development

Palate

The palate has two key stages of development during embryonic and an early fetal involving the fusion of structures (epithelia to mesenchymal).

Embryonic

Primary palate, fusion in the human embryo between stage 17 and 18, from an epithelial seam to the mesenchymal bridge. Stage17-18 Primary palate.gif

Fetal

Secondary palate, fusion in the human embryo in week 9. This requires the early palatal shelves growth, elevation and fusion during the early embryonic period. The fusion event is to both each other and the primary palate. palatal shelf elevation | secondary palate


Links: Palate Development

Ear Auricles

  • form from 6 hillocks (week 5)
  • 3 on each of arch 1 and 2

Tongue Development

Tongue1.png Tongue2.png] Tongue3.png]

  • Ectoderm of the first arch surrounding the stomodeum forms the epithelium lining the buccal cavity.
  • Also the salivary glands, enamel of the teeth, epithelium of the body of the tongue.
    • As the tongue develops "inside" the floor of the oral cavity, it is not readily visible in the external views of the embryonic (Carnegie) stages of development.
  • Contributions from all arches, which changes with time
  • begins as swelling rostral to foramen cecum, median tongue bud
    • Arch 1 - oral part of tongue (ant 3/2)
    • Arch 2 - initial contribution to surface is lost
    • Arch 3 - pharyngeal part of tongue (post 1/3)
    • Arch 4 - epiglottis and adjacent regions

Tongue muscle

tongue muscle
  • Tongue muscles originate from the somites.
    • Tongue muscles develop before masticatory muscles and is completed by birth.
  • Masticatory muscles originate from the somitomeres.
    • These muscles develop late and are not complete even at birth.


Salivary Glands

  • epithelial buds in oral cavity (week 6 to 7) extend into mesenchyme
  • parotid, submandibular, sublingual


Links: Salivary Gland Development | Tongue Development | Development Animation - Tongue

Pharyngeal Arch Tables

Pharyngeal Arch Nerve Artery Neural Crest
(Skeletal Structures)
Muscles Ligaments
1
(maxillary/mandibular)
trigeminal (V) maxillary artery (terminal branches) mandible, maxilla, malleus, incus muscles of mastication, mylohyoid, tensor tympanic, ant. belly digastric ant lig of malleus, sphenomandibular ligament
2
(hyoid)
facial (VII) stapedial (embryonic)

corticotympanic (adult)

stapes, styloid process, lesser cornu of hyoid, upper part of body of hyoid bone muscles of facial expression, stapedius, stylohyoid, post. belly digastric stylohyoid ligament
3 glossopharyngeal (IX) common carotid, internal carotid arteries greater cornu of hyoid, lower part of body of hyoid bone stylopharyngeus
4 vagus (X) superior laryngeal branch part of aortic arch (left), part right subclavian artery (right) thyroid, cricoid, arytenoid, corniculate and cuneform cartilages crycothyroid, soft palate levator veli palatini (not tensor veli palatini)
6 vagus (X) recurrent laryngeal branch part of left pulmonary artery (left), part of right pulmonary artery (right) thyroid, cricoid, arytenoid, corniculate and cuneform cartilages larynx intrinsic muscles (not cricothyroid muscle)

Structures derived from Pouches

Each pouch is lined with endoderm and generates specific structures.


Pouch
Overall Structure Specific Structures
1
tubotympanic recess tympanic membrane, tympanic cavity, mastoid antrum, auditory tube
2
intratonsillar cleft crypts of palatine tonsil, lymphatic nodules of palatine tonsil
3
inferior parathyroid gland, thymus gland
4
superior parathyroid gland, ultimobranchial body
5
becomes part of 4th pouch

Structures derived from Grooves

Only the first groove differentiates into an adult structure and forms part of the external acoustic meatus.

Structures derived from Membranes

At the bottom of each groove lies the membrane which is formed from the contact region of ectodermal groove and endodermal pouch. Only the first membrane differentiates into an adult structure and forms the tympanic membrane.

Movies

There are a number of movies representing development of different features of the head and face.

Face 001 icon.jpg
 ‎‎Face Development
Page | Play
Palate 001 icon.jpg
 ‎‎Palate (oral view)
Page | Play
Palate 002 icon.jpg
 ‎‎Palate (front view)
Page | Play
Tongue 001 icon.jpg
 ‎‎Tongue
Page | Play
Postnatal human mandible growth icon.jpg
 ‎‎Mandible Growth
Page | Play


Links: Head and Face Movies | Movies

References

  1. Nagarajan M, Sharbidre KG, Bhabad SH & Byrd SE. (2018). MR Imaging of the Fetal Face: Comprehensive Review. Radiographics , , 170142. PMID: 29652578 DOI.
  2. Li W, Xu H, Zhao L & Li X. (2018). Branchial anomalies in children: A report of 105 surgical cases. Int. J. Pediatr. Otorhinolaryngol. , 104, 14-18. PMID: 29287855 DOI.
  3. Graham A & Richardson J. (2012). Developmental and evolutionary origins of the pharyngeal apparatus. Evodevo , 3, 24. PMID: 23020903 DOI.
  4. Talbot JC, Johnson SL & Kimmel CB. (2010). hand2 and Dlx genes specify dorsal, intermediate and ventral domains within zebrafish pharyngeal arches. Development , 137, 2507-17. PMID: 20573696 DOI.
  5. Bamforth SD, Chaudhry B, Bennett M, Wilson R, Mohun TJ, Van Mierop LH, Henderson DJ & Anderson RH. (2013). Clarification of the identity of the mammalian fifth pharyngeal arch artery. Clin Anat , 26, 173-82. PMID: 22623372 DOI.
  6. Diogo R, Kelly RG, Christiaen L, Levine M, Ziermann JM, Molnar JL, Noden DM & Tzahor E. (2015). A new heart for a new head in vertebrate cardiopharyngeal evolution. Nature , 520, 466-73. PMID: 25903628 DOI.
  7. Foppiano S, Hu D & Marcucio RS. (2007). Signaling by bone morphogenetic proteins directs formation of an ectodermal signaling center that regulates craniofacial development. Dev. Biol. , 312, 103-14. PMID: 18028903 DOI.


Reviews

Nagarajan M, Sharbidre KG, Bhabad SH & Byrd SE. (2018). MR Imaging of the Fetal Face: Comprehensive Review. Radiographics , , 170142. PMID: 29652578 DOI.

Abramyan J & Richman JM. (2018). Craniofacial development: discoveries made in the chicken embryo. Int. J. Dev. Biol. , 62, 97-107. PMID: 29616744 DOI.

Adameyko I & Fried K. (2016). The Nervous System Orchestrates and Integrates Craniofacial Development: A Review. Front Physiol , 7, 49. PMID: 26924989 DOI.

Kuratani S & Schilling T. (2008). Head segmentation in vertebrates. Integr. Comp. Biol. , 48, 604-10. PMID: 20607135 DOI.

Grevellec A & Tucker AS. (2010). The pharyngeal pouches and clefts: Development, evolution, structure and derivatives. Semin. Cell Dev. Biol. , 21, 325-32. PMID: 20144910 DOI.

Articles

Choe CP & Crump JG. (2015). Dynamic epithelia of the developing vertebrate face. Curr. Opin. Genet. Dev. , 32, 66-72. PMID: 25748249 DOI.

Shone V & Graham A. (2014). Endodermal/ectodermal interfaces during pharyngeal segmentation in vertebrates. J. Anat. , 225, 479-91. PMID: 25201771 DOI.

Thi Thu HN, Haw Tien SF, Loh SL, Bok Yan JS & Korzh V. (2013). Tbx2a is required for specification of endodermal pouches during development of the pharyngeal arches. PLoS ONE , 8, e77171. PMID: 24130849 DOI.

Search PubMed

Search term: Head Development | Pharyngeal Arch Development | | Face Development

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Books

Hinrichsen K. The early development of morphology and patterns of the face in the human embryo. Berlin ; New York : Springer-Verlag, c1985

Additional Images

Historic

Historic Disclaimer - information about historic embryology pages 
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Pages where the terms "Historic Textbook" and "Historic Embryology" appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms and interpretations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)

Development or the Face

Development of the Pharynx and Neck

Terms

Head Terms (expand to view) 
  • branchial arch - see pharyngeal arch.
  • clefting - the way in which the upper jaw forms from fusion of the smaller upper prominence of the first pharyngeal arch leads to a common congenital defect in this region called "clefting", which may involve either the upper lip, the palate or both structures, see palate and head abnormalities.
  • coronal suture - skull term for the fibrous connective tissue joint that connects the frontal bone with the parietal bones.
  • cranial fossae - skull term for the base bones of the cranial vault that form a container and support for the brain.
  • cranial vault - skull term for the space formed by bones of the skull that enclose the brain.
  • cysts - refers to a cervical sinus abnormality, remants of the cervical sinus remains as a fluid-filled cyst lined by an epithelium, see pharyngeal arch and head abnormalities.
  • dolichocephaly - see scaphocephaly.
  • fistula - refers to a pharyngeal membrane abnormality, a tract extends from pharynx (tonsillar fossa) beween the carotid arteries (internal and external) to open on side of neck, see pharyngeal arch and head abnormalities.
  • lambdoid suture (lambdoidal suture) skull term for the fibrous connective tissue joint that connects the parietal bones with the occipital bone, and is continuous with the occipitomastoid suture.
  • metopic suture - skull term for the fibrous connective tissue joint that connects the two fontal bones. In the adult skull this suture is not always present.
  • oxycephaly - (turricephaly) term meaning premature fusion of coronal suture + others, see skull and head abnormalities.
  • pharyngeal arch - (branchial arch) a structure that forms in the cranial region of the embryo having contributions from all germ layers. In humans, the arches appear in week 4 (GA week 6) in a rostra-caudal sequence and are numbered (1, 2, 3, 4, and 6). Each arch contributes a different part of the head and neck and the associated components.
  • pharyngeal cleft - (groove) surface ectoderm that externally separates each pharyngeal arch. In humans, only first pair persist as the outer ear external auditory meatus.
  • pharyngeal groove - see pharyngeal cleft.
  • pharyngeal membrane - surface ectoderm and pharynx endoderm contact region lying between each pharyngeal arch. In humans, only the first membrane pair persist as the tympanic membrane.
  • pharyngeal pouch - pharynx endoderm internal out-pocketing that separates each pharyngeal arch.
  • plagiocephaly - term meaning premature unilateral fusion of coronal or lambdoid sutures, see skull and head abnormalities.
  • Reichardt's cartilage - (pharyngeal arch 2 cartilage) The superior portion of the hyoid forms the ventral portion of this cartilage and the middle ear stapes is thought to form from the ends of this cartilage.
  • sagittal suture - skull term for the fibrous connective tissue joint that connects the two parietal bones in the midline.
  • scaphocephaly - (dolichocephaly) term meaning premature fusion of sagittal suture, see skull and head abnormalities.
  • sinuses - refers to a pharyngeal groove (cleft) abnormality, when a portion of the pharyngeal groove persists and opens to the skin surface, located laterally on the neck, see pharyngeal arch and head abnormalities.
  • squamosal suture - skull term for the fibrous connective tissue joint that connects the squamous portion of the temporal bone with the parietal bones.
  • suture - skull term for a fibrous connective tissue joint. In humans, the main sutures are coronal, sagittal, lambdoid and squamosal sutures, with the metopic suture (frontal suture) occurring as an anatomical variant in the adult skull.
  • turricephaly - see oxycephaly.
Other Terms Lists  
Terms Lists: ART | Birth | Bone | Cardiovascular | Cell Division | Endocrine | Gastrointestinal | Genetic | Head | Hearing | Heart | Immune | Integumentary | NeonatalNeural | Oocyte | Palate | Placenta | Radiation | Renal | Respiratory | Spermatozoa | Statistics | Ultrasound | Vision | Historic | Drugs | Glossary


Palate Development (expand to see terms)  
  • cleft - An anatomical gap or space occuring in abnormal development in or between structures. Most commonly associated with cleft lip and cleft palate. Term is also used to describe the external groove that forms between each pharyngeal arch during their formation.
  • cleft lip - An abnormality of face development leading to an opening in the upper lip. Clefting of the lip and or palate occurs with 300+ different abnormalities. Depending on many factors, this cleft may extend further into the oral cavity leading to a cleft palate. In most cases clefting of the lip and palate can be repaired by surgery.
  • cleft palate - An abnormality of face development leading to an opening in the palate, the roof of the oral cavity between the mouth and the nose. Clefting of the lip and or palate occurs with 300+ different abnormalities. In most cases clefting of the lip and palate can be repaired by surgery. Palate formation in the embryo occurs at two distinct times and developmental processes called primary and secondary palate formation. This leads to different forms (classifications) and degrees of clefting.
  • hard palate - anterior part of the palate that becomes ossified. The posterior palate part is the soft palate.
  • epithelial mesenchymal transition - (EMT, epitheliomesenchymal transformation) conversion of an epithelium into a mesenchymal (connective tissue) cellular organization. Process required during lip and palate developmental fusion.
  • epitheliomesenchymal transformation - (epithelial mesenchymal transition) conversion of an epithelium into a mesenchymal (connective tissue) cellular organization.
  • incisive papilla - anterior midline palate near the incisors lying at the end of the palatine raphe.
  • levator veli palatini - Muscle forming part of the soft palate, elevates the soft palate for swallowing.
  • mastication - (chewing) Process of crushing and grinding food within the mouth.
  • maxilla - (pl. maxillae) upper jaw bone forming from the maxillary process of the first pharyngeal arch.
  • medial edge epithelial - (MEE) opposing palatal shelves adhere to each other to form this epithelial seam.
  • musculus uvulae Small muscle forming part of the soft palate lying within the uvula, shortens and broadens the uvula.
  • palatine raphe (median raphe) palate midline ridge (seam) of the mucosa, from the incisive papilla to the uvula.
  • palatal rugae - (palatine rugae, rugae) Transverse series of ridges forming on the secondary hard palate that are sequentially added during development as the palate grows. Involved in the process of mastication.
  • palatal vault - (palatine vault) Term describing the curved "arch" shape of the palate that mainly develops postnatally.
  • palate - The roof of the mouth (oral cavity) a structure which separates the oral from the nasal cavity. Develops as two lateral palatal shelves which grow and fuse in the midline. Initally a primary palate forms with fusion of the maxillary processes with the nasal processes in early face formation. Later the secondary palate forms the anterior hard palate which will ossify and separate the oral and nasal cavities. The posterior part of the palate is called the soft palate (velum, muscular palate) and contains no bone. Abnormalities of palatal shelf fusion can lead to cleft palate.
  • palatine bones - Two bones that with the maxillae form the hard palate.
  • palatogenesis - The process of palate formation, divided into primary and secondary palate development.
  • palatoglossus - (glossopalatinus, palatoglossal muscle) Small muscle forming part of the soft palate required for swallowing.
  • palatopharyngeus - (palatopharyngeal or pharyngopalatinus) Small muscle forming part of the soft palate required for breathing.
  • pharyngeal arch - (branchial arch, Greek, branchial = gill) These are a series of externally visible anterior tissue bands lying under the early brain that give rise to the structures of the head and neck. In humans, five arches form (1,2,3,4 and 6) but only four are externally visible on the embryo. Each arch has initially identical structures: an internal endodermal pouch, a mesenchymal (mesoderm and neural crest) core, a membrane (endoderm and ectoderm) and external cleft (ectoderm). Each arch mesenchymal core also contains similar components: blood vessel, nerve, muscular, cartilage. Each arch though initially formed from similar components will differentiate to form different head and neck structures.
  • philtrum - (infranasal depression, Greek, philtron = "to love" or "to kiss") Anatomically the surface midline vertical groove in the upper lip. Embryonically formed by the fusion of the frontonasal prominence (FNP) with the two maxillary processes of the first pharyngeal arch. Cleft palate (primary palate) occurs if these three regions fail to fuse during development. Fetal alcohol syndrome is also indicated by flatness and extension of this upper lip region.
  • soft palate - (velum, muscular palate) posterior part of the palate that becomes muscular. Forms 5 muscles: tensor veli palatini, palatoglossus, palatopharyngeus, levator veli palatini, musculus uvulae. The anterior palate part is the hard palate.
  • T-box 22 - (TBX22) a transcription factor that cause X-linked cleft palate and ankyloglossia in humans. Tbx22 is induced by fibroblast growth factor 8 (FGF8) in the early face while bone morphogenic protein 4 (BMP4) represses and therefore restricts its expression. (More? OMIM - TBX22)
  • tensor veli palatini - (tensor palati, tensor muscle of the velum palatinum) Small muscle forming part of the soft palate required for swallowing.
  • Transforming Growth Factor-beta - (TGFβ) factors induces both epithelial mesenchymal transition and/or apoptosis during palatal medial edge seam disintegration.
  • uvula - (Latin = a little grape) a pendulous posterior end of soft palate used to produce guttural consonants. First named in 1695.
  • Van der Woude syndrome - common syndromic cause of clefting (2% of cleft lip and palates). Van der Woude syndrome 1 1q32.2 Van der Woude syndrome 2 1p36.11
  • velopharyngeal insufficiency - (VPI) associated with cleft palate repair, describes the velum and lateral and posterior pharyngeal walls failing to separate the oral cavity from the nasal cavity during speech.
Other Terms Lists  
Terms Lists: ART | Birth | Bone | Cardiovascular | Cell Division | Endocrine | Gastrointestinal | Genetic | Head | Hearing | Heart | Immune | Integumentary | NeonatalNeural | Oocyte | Palate | Placenta | Radiation | Renal | Respiratory | Spermatozoa | Statistics | Ultrasound | Vision | Historic | Drugs | Glossary

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Cite this page: Hill, M.A. (2018, July 20) Embryology Head Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Head_Development

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