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DEVELOPMENT OF HEAD AND NECK

DEVELOPMENT OF HEAD AND NECK. Carnegie 13 (28 – 32 days) 4 – 6 mm, 30 somites. Vývoj hlavy, krku. pharyngeal arches. lips oral cavity oral vestibule teeth tongue hard palate soft palate pharynx larynx. parotid gland submandibular gland sublingual gland. thyroid gland

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DEVELOPMENT OF HEAD AND NECK

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  1. DEVELOPMENT OF HEAD AND NECK

  2. Carnegie 13 (28 – 32 days) 4 – 6 mm, 30 somites Vývoj hlavy, krku pharyngeal arches

  3. lips • oral cavity • oral vestibule • teeth • tongue • hard palate • soft palate • pharynx • larynx

  4. parotid gland • submandibular gland • sublingual gland

  5. thyroid gland • parathyroid gland • 4 bodies • thymus http://www.mayoclinic.com/images/image_popup/pthyroid.jpg

  6. 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

  7. 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)

  8. 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

  9. Pharyngeal arches (arcus pharyngei) • paired structures • begin to develop in the 4th – 5thweek • 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)

  10. 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

  11. Aortic arches(Aa. arcuum pharyngeorum)

  12. 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

  13. 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

  14. Derivatives of aortic arches • 5th pair – Ø • 6th pair • leftproximally: arteria pulmonalis sinistra • left distally: ductus arteriosus (Botali) • right proximally: arteria pulmonalis dextra • right distally: Ø

  15. 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

  16. 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

  17. 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.)

  18. Fifth pharyngeal arch • does not arise in human at all Sixth pharyngeal arch • merges with 4th arch • muscles of larynx • innervation: n.X(n. laryngeus recurrens) • containing fibres from n.XI

  19. Pharyngeal pouches (sacci pharyngei) • human embryo has 5 pouches • their endoderm gives rise to branchiogenic organs Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  20. 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)

  21. Second pharyngeal pouch • base of palatine tonsil (tonsilla palatina) • fossa supratonsillaris http://biology.clc.uc.edu/fankhauser/labs/microbiology/strep_detection/strep_test.htm

  22. Third pharyngeal pouch • dorsal part • inferior parathyroid bud • ventral part • thymic bud • bases migrate caudally

  23. 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)

  24. 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

  25. Lateral cervical fistula http://journals.tums.ac.ir/full_text.aspx?org_id=59&culture_var=en&journal_id=4&issue_id=1293&manuscript_id=11415&segment=en http://www.ultratwistersgym.com/Resources/Head/Head%20and%20Neck.html

  26. Innervation of tongue • n. V3 • n. lingualis • n. VII • chorda tympani • n. IX • n. X

  27. Development of tongue • 4th week: primordia lingualiaappear 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)

  28. Development of tongue Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  29. 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

  30. Ankyloglossia http://www.ghorayeb.com/TongueTie.html

  31. Macroglossia - Microglossia http://www.consultantlive.com/display/article/10162/43839 http://dentallecnotes.blogspot.cz/2011/08/developmental-disturbances-of-tongue.html

  32. 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 ofductus 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

  33. 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

  34. Thyroglossal duct cysts http://www.surgical-tutor.org.uk/default-home.htm?tutorials/thyroglossal.htm~right http://www.learningradiology.com/archives06/COW%20231-Thyroglossal%20Duct%20Cyst/tgdccorrect.html

  35. 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

  36. DiGeorge syndromeAplasia thymoparathyroidea microdeletion 22q11.2 1:3000

  37. 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

  38. Development of face Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  39. 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

  40. 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

  41. 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)

  42. Development of palate Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  43. Separation of oral and nasal cavity Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  44. 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

  45. 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

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