View
221
Download
0
Category
Preview:
Citation preview
DEVELOPMENT OF HEAD AND NECK
© David Kachlík 30.9.2015
Vývoj hlavy, krku
pharyngeal
arches
Carnegie 13 (28 – 32 days)
4 – 6 mm, 30 somites
© David Kachlík 30.9.2015
• lips
• oral cavity
– oral vestibule
• teeth
• tongue
• hard palate
• soft palate
• pharynx
• larynx
© David Kachlík 30.9.2015
• parotid gland
• submandibular
gland
• sublingual
gland
© David Kachlík 30.9.2015
• thyroid gland
• parathyroid gland
– 4 bodies
• thymus
http://www.mayoclinic.com/images/image_popup/pthyroid.jpg
© David Kachlík 30.9.2015
Development of the digestive tube
• primitive gut • formed during the 4th week, as the head, tail and
lateral folds incorporate a part of the yolk sack into
the embryo
– foregut (preentereon) – separated from
stomodeum (primitive mouth) by membrana
oropharyngea, protrusion of base of lower
respiratory tract
– midgut (mesenteron) – aborally from liver bud
to Cannon-Böhm point
– hindgut (metenteron) – further, separated from
proctodeum (anal pit) by membrana cloacalis© David Kachlík 30.9.2015
Origin of mesenchyme
• paraaxial mesoderm (non-segmented)– bones of skull base and some of bones of calvaria
– all skeletal muscles
– dermis and fibrous tissue on the dorsal part of head
• ectomesenchyme (from the neural crest)– skeleton of face and pharyngeal arches
• ectodermal placodes (thickened areas of ectoderm)
• pharyngeal arches
• occipital segments (basis et condyli ossis occipitalis)
© David Kachlík 30.9.2015
Pharyngeal apparatus• pharyngeal arches (arcus pharyngei)
• pharyngeal pouches (sacci pharyngei)
• pharyngeal grooves (sulci pharyngei)
• pharyngeal membranes (membranae
pharyngeae)
Thomas W. Sadler, Langman´ Medical embryology, 10th edition
© David Kachlík 30.9.2015
Pharyngeal arches (arcus pharyngei)
• paired structures
• begin to develop in the 4th – 5th week
• separation of columns of mesenchyme:
– pharyngeal grooves on external side
(depressions in ectoderm)
–pharyngeal pouches on internal side
(formed by endoderm of primitive larynx)
–grooves and pouches never merge (no gills
form)© David Kachlík 30.9.2015
Pharyngeal arches (arcus pharyngei)
• mesenchyme of neural crest cells is
streaked by para-axial mesoderm and in
each pharyngeal arch gives rise to
muscles
• cartilages and skeleton of arches are
differentiated from ectomesenchyme
• each arch is innervated by a cranial nerve
and has its own artery (aa. arcuum
pharyngeorum = aortic arches)
• 5th arch does not arise© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
Aortic arches
(Aa. arcuum pharyngeorum)
© David Kachlík 30.9.2015
Derivatives of aortic arches
• 1st pair – arteria maxillaris + a. carotis externa
• 2nd pair – arteria stapedia
• 3rd pair – proximally - arteria carotis communis
– distally - arteria carotis interna
© David Kachlík 30.9.2015
Derivatives of aortic arches
• 4th pair
– left – part of arcus aortae
– right – arteria subclavia dx.
• distal part of a. subclavia dx. arises from aorta dorsalis dextra
– a. subclavia sin. is not derived from aortic arch but
from the 7th intersegmental artery
© David Kachlík 30.9.2015
Derivatives of aortic arches
• 5th pair – Ø
• 6th pair
– left proximally: arteria pulmonalis sinistra
– left distally: ductus arteriosus (Botali)
– right proximally: arteria pulmonalis dextra
– right distally: Ø
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
arch nerve muscles skeletal structures ligaments arteries
1. mandibular
(maxillary
and
mandibular
process)
n. trigeminus muscles of mastication
(m. temporalis, m.
masseter, m.
pterygoideus medialis et
lateralis)
m. mylohyoideus, venter
anterior m. digastrici
m. tensor tympani
m. tensor veli palatini
premaxilla, maxilla, os
palatinum, os
zygomaticum, squama
ossis temporalis,
Meckel´s cartilage,
mandibula, malleus,
incus
lig. mallei ant.,
lig.
sphenomandibulare
a. maxillaris
2. hyoid n. facialis muscles of facial
expression
(m. buccinator, mm.
auriculares, m. frontalis,
platyzma, m. orbicularis
oris et oculi)
m. stapedius
m. stylohyoideus, venter
posterior m. digastrici
stapes,
processus styloideus,
cornua minora et
corpus ossis hyoidis
(upper part)
lig. stylohyoideum a. stapedia
3. arch n.glossopharyngeus m. stylopharyngeus cornua majora et
corpus ossis hyoidis
(lower part)
a. carotis communis
a. carotis interna
(proximal part of pars
cervicalis)
4. left n. laryngeus superior
(n.X)
m. cricothyroideus, m.
levator veli palatini, m.
constrictor pharyngis
med. et inf.,
intrinsic muscles of
larynx
striated muscles of the
oesophagus
5th arch is missing
cartilaginous parts of the
4th and 6th arch merge
into a common base of
the cartilages of the
larynx
cartilago thyroidea,
cricoidea, arytenoidea,
corniculata,
cuneiformis
arcus ortae from a.
carotis communis sin. to
a. subclavia sin
right prox. part of a.subclavia dx.
6. left n. laryngeus recurrens
(fibres from n.
accessorius using n.
vagus)
a.pulmonalis sin., ductus
arteriosus
right a.pulmonalis dx.
© David Kachlík 30.9.2015
First pharyngeal arch
(arcus pharyngeus primus)
• 2 processes
– maxillary (cranially)
– mandibular (caudally)
• contains the Meckel´s cartilage (gives rise to
malleus and incus)
• formation of the lower jaw
– merging of the right and left mandibular
process, subsequent membranous
ossification
Thomas W. Sadler, Langman´ Medical embryology, 10th edition
© David Kachlík 30.9.2015
Second pharyngeal arch
(arcus pharyngeus secundus)
• cartilage (= Reichert´s cartilage)
• by merging of right and left arch in the midline → part of body and lesser horns of hyoid bone are formed
Thomas W. Sadler, Langman´ Medical embryology, 10th edition
© David Kachlík 30.9.2015
Third pharyngeal arch
• cornua majora + caudal part of corpus ossis
hyoidei
• innervation: n. IX
Fourth pharyngeal arch
• merges with 6th arch
• cartilago cricoidea + thyroidea
• muscles of larynx, palate (apart from m.
tensor veli palatini), pharynx (apart from m.
stylopharyngeus)
• innervation: n. X (n. laryngeus sup.)© David Kachlík 30.9.2015
Fifth pharyngeal arch
• does not arise in human at all
• merges with 4th arch
• muscles of larynx
• innervation: n.X (n. laryngeus recurrens)
• containing fibres from n.XI
Sixth pharyngeal arch
© David Kachlík 30.9.2015
Pharyngeal pouches (sacci pharyngei)
• human embryo has 5 pouches
• their endoderm gives rise to branchiogenic
organs
Thomas W. Sadler, Langman´ Medical embryology, 10th edition
© David Kachlík 30.9.2015
First pharyngeal pouch
• recessus tubotympanicus (tubotympanic
recess)
– blind recess (toward 1st pharyngeal groove)
• its end is widened into primitive tympanic
cavity
• medial part remains straight → tuba
auditiva Eustachii
• together with 1st pharyngeal groove it
participates in formation of eardrum
(membrana tympanica)© David Kachlík 30.9.2015
Second pharyngeal pouch
• base of palatine tonsil (tonsilla palatina)
• fossa supratonsillaris
http://biology.clc.uc.edu/fankhauser/labs/microbiology/strep_detection/strep_test.htm
© David Kachlík 30.9.2015
Third pharyngeal pouch
• dorsal part
– inferior parathyroid bud
• ventral part
– thymic bud
• bases migrate caudally
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
Fourth pharyngeal pouch
• dorsal part
– superior parathyroid bud
• ventral part
– rudimentary
– ultimopharyngeal body (corpus
ultimopharyngeum / ultimobranchialis)
• cells from neural crest
• differentiate into parafolicular (C-cells) of thyroid
gland (producing calcitonin)
© David Kachlík 30.9.2015
Pharyngeal grooves (Sulci pharyngei)
• 4 pairs of grooves are formed within 5th week
• dorsal part of 1st groove persists as external acoustic meatus (meatus acusticus externus)
– epithelium on floor formes outer surface of eardrum (membrana tympanica)
• other grooves come to lie in a depression cervical sinus (sinus cervicalis)
• sinus cervicalis is obliterated as the neck develops, lateral cervical cysts may persist fistulae © David Kachlík 30.9.2015
Lateral cervical fistula
http://www.ultratwistersgym.com/Resources/Head/Head%20and%20Neck.htmlhttp://journals.tums.ac.ir/full_text.aspx?org_id=59&culture_var=en&journal_id=4&issue_id=1293&manuscript_id=11415&segment=en
© David Kachlík 30.9.2015
Innervation of tongue
• n. V3 –n. lingualis
• n. VII – chorda tympani
• n. IX
• n. X
© David Kachlík 30.9.2015
Development of tongue• 4th week: primordia lingualia appear on inner side of
pharyngeal pouches
• 1st arch: tuberculum impar (fades out) + 2 tubercula lingualia lateralia apex + dorsum linguae (n.V3)
• 2nd arch: copula (wears off) – n.VII – chorda tympani (taste)
• 3rd-4th arch: eminentia hypopharyngea radix linguae (n.IX, n.X)– sulcus terminalis (separates the body and the root of the
tongue)
• 4th arch epiglottis (n. X)
• muscles:– from myotomes of occipital somites (n. XII)
– from 4th pharyngeal arch (n. X – only m. palatoglossus)© David Kachlík 30.9.2015
Development of tongue
Thomas W. Sadler, Langman´ Medical embryology, 10th edition
© David Kachlík 30.9.2015
Congenital defects of tongue
• cysts and fistulae – remnants of the
thyroglossal duct
• ankyloglossia (t= ongue-tie)
– short frenulum linguae
• macroglossia
• microglossia
• glossoschissis (= cleft tongue)
– rare, incomplete cleft
© David Kachlík 30.9.2015
Ankyloglossia
http://www.ghorayeb.com/TongueTie.html
© David Kachlík 30.9.2015
Macroglossia - Microglossia
http://www.consultantlive.com/display/article/10162/43839 http://dentallecnotes.blogspot.cz/2011/08/developmental-disturbances-of-tongue.html
© David Kachlík 30.9.2015
Development of the thyroid gland
• growth of epithelium between tuberculum impar and copula → location of foramen caecum
• growths in front of pharynx in a caudal direction
• within the descent is connected to tongue by means of ductus thyroglossus
• progressive descent in front of hyoid bone and cartilages of larynx
• within 7th week gets to its final place in front of trachea
• gets functional at the end of 3rd month© David Kachlík 30.9.2015
Congenital defects of thyroid gland
• thyroglossal duct cysts
– may develop anywhere along the course of
descent of thyroid gland from the tongue
• thyroglossal duct fistulae
– communication of cysts with external space
• ectopic thyroid gland
– along the course of descent
– most often at root of tongue
– this tissue may be functional© David Kachlík 30.9.2015
Thyroglossal duct cysts
http://www.learningradiology.com/archives06/COW%20231-Thyroglossal%20Duct%20Cyst/tgdccorrect.html
http://www.surgical-tutor.org.uk/default-home.htm?tutorials/thyroglossal.htm~right
© David Kachlík 30.9.2015
Processus pyramidalis
glandulae thyroideae
• the most common congenital defect
• along the course of the descent
• 40 %
http://www.anatomyatlases.org/AnatomicVariants/OrganSystem/Images/82.shtml
© David Kachlík 30.9.2015
DiGeorge syndrome
Aplasia thymoparathyroideamicrodeletion 22q11.2
1:3000
© David Kachlík 30.9.2015
Development of face
facial primordia appear at end of 4th week (neural crest
ectomesenchyme of 1st pharyngeal arch) around
stomodeum
• frontonasal prominence cranially
• maxillary prominences laterally
• mandibular prominences caudally
– on each side develop bilateral oval thickenings of
the surface ectoderm nasal placodes
• they depress within 5th week nasal pits
• pits are bordered by horseshoe-shaped
elevations = medial and lateral nasal
prominences © David Kachlík 30.9.2015
Development of face
Thomas W. Sadler, Langman´ Medical embryology, 10th edition
© David Kachlík 30.9.2015
Development of face• maxillary prominences enlarge (cheeks and upper
jaw) and growth medially
• pressing medial nasal prominences to the midline
→ then they merge
• upper lip is formed by the maxillary prominences
and medial nasal prominences
• lower lip and jaw are formed by mandibular
prominences that merge in the midline
• nose arises from 5 sources:
– frontonasal prominence, 2 medial nasal
prominences, 2 lateral nasal prominences© David Kachlík 30.9.2015
Development of
oral and nasal cavity
stomodeum
• a pit lined with ectoderm
boundaries:
• lower processes of 1st pharyngeal arch – mandibula
• on sides upper processes of 1st pharyngeal arch –maxilla
• frontonasal prominence with nasal placodes from above ( pits, vesicles, open into the primitive oral cavity), medial and lateral nasal prominences
• membrana oropharyngea (buccopharyngea) breaks up on 26th day
© David Kachlík 30.9.2015
Development of palate
• primary palate– from intermaxillary segment
• by merging of both medial nasal prominences)
– lip component philtrum
– component for the upper jaw (carries 4 incisors)
– palatine component (forms the primary palate)
– passes continuously into nasal septum (from frontonasal prominence)
• secondary palate– by merging of palatine processes of maxillary
process (6th week)
– ventrally fusion with primary palate (future os incisivum) © David Kachlík 30.9.2015
Development of palate
Thomas W. Sadler, Langman´ Medical embryology, 10th edition
© David Kachlík 30.9.2015
Separation of oral and nasal cavity
Thomas W. Sadler, Langman´ Medical embryology, 10th edition
© David Kachlík 30.9.2015
Cleft malformations of face and palate
• impaired fusion of structures (1:550)
• anterior palate clefts (cheiloschisis, cheilognathoschisis)
– lateral lip, upper jaw cleft, cleft between the primary and secondary palates
–partial or complete lack of fusion of maxillary prominence with medial nasal prominence on one or both sides
• posterior palate clefts (palatoschisis)
–secondary palate cleft, uvula cleft
© David Kachlík 30.9.2015
Cleft malformations of face and palate
• combination of clefts lying anterior as well as posterior to incisive foramen (cheilo-gnatho-palatoschisis)
• oblique facial clefts
– failure in merging of maxillary prominence with its corresponding lateral nasal prominence
• median (midline) lip cleft
– rare abnormality
– incomplete merging of two medial nasal prominences in the midline
© David Kachlík 30.9.2015
Cleft malformations of face and palate
http://www.craniofacial.net/cleft-lip-cleft-palate-only
http://blog.johnrchildress.com/2011/06/07/real-leadership-and-hope/
Thomas W. Sadler, Langman´ Medical embryology, 10th edition
© David Kachlík 30.9.2015
Cleft malformations of face and palate
http://www.rodina.cz/clanek3188.htm
beforebefore
afterafter
© David Kachlík 30.9.2015
Development of salivary glands
• epithelial pouches of oral cavity (6th – 8th
week)
• intergrowth into adjacent ectomesenchyme
its connective tissue comes from neural
crest
• parenchyme ( secretion) comes from
proliferating oral epithelium
– ectoderm gl. parotidea
– endoderm gl. submandibularis et sublingualis © David Kachlík 30.9.2015
Development of teeth6th week: proliferation of oral epithelium
(ectoderm) into surrounding
ectomesenchyme
• dental lamina (parallell to labiogingival crest)
• ectoderm → enamel organ
– outer enamel epithelium
– stratum intermedium, stellate reticulum
– inner enamel epithelium (ameloblasts)
• ectomesenchyme → dental papilla
(odontoblasts)© David Kachlík 30.9.2015
Development of teeth• production of dentine
– odontoblasts: procollagen → predentin → dentin• with thickening of dentine layer, odontoblasts retreat into the
dental papilla, leaving a thin cytoplasmic processes (dental processes or Tomes fibres)
• production of enamel– basal surface of ameloblasts becomes secretory:
• enamel matrix (organic – mineralisation)
• development of roots• dental epithelial layers penetrate into the underlying
mesenchyme root sheath
• mesenchymal cells on the outside of tooth and in contact with dentin of root differentiate into cementoblasts
• permanent teeth• secondary dental lamina is located lingually to primary one
© David Kachlík 30.9.2015
Development of teeth
Thomas W. Sadler, Langman´ Medical embryology, 10th edition
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
© David Kachlík 30.9.2015
Recommended