Branchial pharyngeal arches_concise /certified fixed orthodontic courses by Indian dental academy

  • 431 views
Uploaded on


The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
431
On Slideshare
0
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
0
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Head and Neck Embryology INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  • 2. Branchial and Pharyngeal Arches  Fourth week  Neural crest cells – Most skeletal and connective tissue in H&N  Numbered cranial  caudal  Four well-defined pairs visible externally  Fifth and sixth rudimentary  Separated by grooves www.indiandentalacademy.com
  • 3. Branchial and Pharyngeal Arches  First = Mandibular – Mandibular Prominence  jaw – Maxillary Prominence  maxilla/zyg/temp  Second = Hyoid www.indiandentalacademy.com
  • 4. www.indiandentalacademy.com
  • 5. Branchial and Pharyngeal Arches  Fate – Typical arch contains • Aortic arch • Cartilaginous rod (skeleton of arch) • Muscular component • Nerve www.indiandentalacademy.com
  • 6. Branchial and Pharyngeal Arches www.indiandentalacademy.com
  • 7. Pharyngeal Pouches  First – Tubotympanic recess  tympanic membrane – Connects with pharynx  eustachian tube  Second – Palatine tonsil, tonsillar fossa  Third – Inferior parathyroid gland – Thymus www.indiandentalacademy.com
  • 8. Pharyngeal Pouches  Fourth – Superior parathyroid gland – Ultimobranchial body fuses with thyroid – Parafollicular C cells  calcitonin  Fifth – Rudimentary www.indiandentalacademy.com
  • 9. www.indiandentalacademy.com
  • 10. Pharyngeal Pouches www.indiandentalacademy.com
  • 11. Branchial or Pharyngeal Grooves  Four on each side  Separate branchial or pharyngeal arches  First  External acoustic meatus  Others lie in depression (cervical sinus) which obliterates www.indiandentalacademy.com
  • 12. Branchial or Pharyngeal Grooves www.indiandentalacademy.com
  • 13. Branchial or Pharyngeal Membranes  Only one pair contribute to adult structures  First  tympanic membrane www.indiandentalacademy.com
  • 14. Branchial and Pharyngeal Anomalies  Congenital Auricular Sinuses and Cysts – Small sinuses (pits) and cysts commonly found in a triangular area of skin anterior to the ear – May be remnant of branchial or pharyngeal groove www.indiandentalacademy.com
  • 15. Branchial and Pharyngeal Anomalies  Branchial Sinuses – Lateral cervical: Uncommon, open externally (neck), failure of second groove or cervical sinus to obliterate – External branchial sinuses: Mucous d/c from infant’s neck, bilateral in 10% – Internal branchial sinuses: Rare, persistent second pouch, open into intratonsillar cleft www.indiandentalacademy.com
  • 16. Branchial and Pharyngeal Anomalies  Branchial Fistula – Connection between intratonsillar cleft and neck – Runs between internal and external carotids – Persistent second groove and second pouch www.indiandentalacademy.com
  • 17. Branchial and Pharyngeal Anomalies  Branchial Cysts – Develop along anterior border of sternocleidomastoid – Most inferior to angle of mandible – Often present in adulthood – Remnants of cervical sinus and/or second groove www.indiandentalacademy.com
  • 18. Branchial and Pharyngeal Anomalies  Branchial Vestiges – Cartilaginous or bony remnants – Usually anterior to inferior third of sternocleidomastoid www.indiandentalacademy.com
  • 19. Branchial and Pharyngeal Anomalies  First Arch Syndrome  First branchial or pharyngeal arch – Treacher Collins syndrome • Malar hypoplasia, down- slanting of palpebral fissures, lower eyelid colobomas, ear deformations – Pierre Robin syndrome • Hypoplasia of the mandible, cleft palate, and defects of the eye and ear www.indiandentalacademy.com
  • 20. Branchial and Pharyngeal Anomalies  DiGeorge Syndrome (Congenital Thymic and Parathyroid Aplasia) – Failure of third and fourth pouches to differentiate into thymus and parathyroid glands – Hypoparathyroidism – Increased incidence of infections – Shortened philtrum – Low-set notched ears – Nasal clefts – Thyroid hypoplasia – Cardiac anomalies www.indiandentalacademy.com
  • 21. Branchial and Pharyngeal Anomalies  Accessory Thymic Tissue – Isolated portion of thymic tissue may persist – Often in close association with inferior parathyroid gland www.indiandentalacademy.com
  • 22. Branchial and Pharyngeal Anomalies  Ectopic Parathyroid Gland – Variable in number (2- 6) and location – Superior more constant than inferior – Thyroid to thorax  Absence of Parathroid Gland www.indiandentalacademy.com
  • 23. Thyroid Gland  Begins as thickening in the floor of the pharynx  Forms an outpouching (thyroid diverticulum)  Descends into neck passing ventral to hyoid bone and laryngeal cartilages  Connected to tongue by thryoglossal duct at foramen cecum www.indiandentalacademy.com
  • 24. Thyroid Gland  Isthmus connects right and left lobes  Thyroglossal duct degenerates  Blind pit marks the foramen cecum  Pyramidal lobe extends superiorly from the isthmus in fifty per cent www.indiandentalacademy.com
  • 25. Thyroid Anomalies  Thyroglossal Duct Cysts and Sinuses – May form anywhere along the course followed by the thyroglossal duct – Most seen by 5 yo – Asymptomatic unless infected – Midline, painless, moveable neck mass – Sinuses are open, cysts are closed www.indiandentalacademy.com
  • 26. Thyroid Anomalies  Ectopic Thyroid Gland – Lingual thyroid • Result of failure to descend • Often only thyroid tissue present – Accessory thyroid tissue • Tongue • Neck, superior or lateral to thyroid www.indiandentalacademy.com
  • 27. Tongue  General – Merged distal tongue buds  anterior 2/3 – Copula and hypobranchial eminence  posterior 1/3 – Terminal sulcus divides anterior and posterior  Taste buds – Most are filiform papillae and are sensitive to touch  Muscles – Supplied by XII except for palatoglossus (X) www.indiandentalacademy.com
  • 28. Tongue  Nerves – Sensory for anterior 2/3 is from V3 (lingual) – Chorda tympani (VII) taste buds for anterior 2/3 (except for vallate papillae supplied by IX) – IX supplies posterior 1/3 – X (Superior Laryngeal) supplies area around epiglottis www.indiandentalacademy.com
  • 29. Tongue  Taste buds – Most are filiform papillae and are sensitive to touch www.indiandentalacademy.com
  • 30. Tongue Anomalies  Lingual cysts and Fistulas – Persistence of thyroglossal duct open to foramen cecum  Ankyloglosia (Tongue- Tie) – Short frenulum to tip, stretches with time  Macroglossia – Usually from muscular hypertrophy or lymphangioma  Microglossia – Associate with micrognathia and limb defects (Hanhart’s syndrome)  Bifid or Cleft Tongue (Glossochisis) – Incomplete fusion of distal tongue buds  deep median sulcus www.indiandentalacademy.com
  • 31. Ear  Three anterior hillocks of the first branchial arch form the tragus, helical crus, and superior helix  Three posterior hillocks of the second branchial arch form the antihelix, antitragus, and lobule  First branchial groove forms external auditory meatus  Microtia – 1:6000-8000 births – Associated with hemifacial microsomia  Nerves – Great auricular (C2, C3)  lower lateral/lower cranial – Auriculotemporal (V3)  superolateral/ anterior and superior external auditory canal – Lesser occipital  superior cranial – Arnold’s (X) concha / posterior auditory canal (referred oropharyngeal pain) www.indiandentalacademy.com
  • 32. Ear www.indiandentalacademy.com
  • 33. Face  Stomodeum is primitive mouth  Five facial primordia appear as prominences around stomodeum – Single fronto(forehead)nasal{ most of nose(except septum/alae)} prominence  optic vesicles  eyes – Paired maxillary prominences  lateral upper lip, most of maxilla, secondary palate – Paired mandibular prominences  chin, lower lip, lower cheek www.indiandentalacademy.com
  • 34. Face  Mandible forms first  Nasal placodes  nasal pits  Six auricular hillocks  ear  Epithelial cord canalizes in nasolacrimal groove  nasolacrimal duct – Atresia if canalization fails www.indiandentalacademy.com
  • 35. Face  Lateral nasal prominence  nasal alae  Medial nasal prominences merge  intermaxillary segment  philtrum of lip, premaxilla (gum), primary palate, nasal septum  Second arch  muscles of facial expression (VII)  First arch  muscles of mastication (V) www.indiandentalacademy.com
  • 36. Face  Labiogingival lamina  lips and gingivae, lingual frenulum  Changes – Early fetal period: Flat nose and underdeveloped mandible – Enlarging brain: Prominent forehead, medial movement of eyes and external ears rise www.indiandentalacademy.com
  • 37. Nasal Cavities  Nasal placodes  nasal pits  deepening  nasal sacs  Oronasal membrane separates the oral cavity from the nasal sacs  Membrane ruptures  primitive chonae (opening b/w nasal cavity and nasopharynx) www.indiandentalacademy.com
  • 38. Nasal Cavities  Olfactory system – Ectodermal epithelium in the roof of each nasal cavity  specialized  olfactory epithelium – Some epithelial cells  olfactory receptors (axons become olfactory nerve) and grow into bulbs of the brain www.indiandentalacademy.com
  • 39. Nasal Cavities  Paranasal sinuses – From outgrowths of nasal cavity walls  pneumatic (air-filled) extensions of the nasal cavities in adjacent bones – Original openings of the outgrowths persist as the orifices of the adult sinuses – Most are rudimentary in newborns • Frontal sinuses are visible by seven • Sphenoidal sinuses usually evident by two – Vomeronasal cartilage  narrow cartilage strips between the inferior edge of the cartilage of nasal septum and vomer www.indiandentalacademy.com
  • 40. Palate  Palatogenesis from 5th – 12th week  Primary Palate – Median palatine process begins to develop from deep intermaxillary segment of maxilla – Primary palate forms the premaxillary part of the maxilla – Represents a small part of the adult hard palate (anterior to the incisive foramen that lodges the incisor teeth) www.indiandentalacademy.com
  • 41. Palate  Secondary Palate – Primordium of hard and soft palates that extend posteriorly from the incisive foramen – Shelf-like structures called lateral palatine processes (palatine shelves) project inferiomedially on each side of the tongue www.indiandentalacademy.com
  • 42. Palate  Secondary Palate – Shelves elongate and ascend to a horizontal position superior to the tongue – Shelves fuse in a median plane with nasal septum and posterior primary palate – Elevation to the horizontal position is thought to be caused by the intrinsic shelf elevating force by hydration of hyaluronic acid in the shelves www.indiandentalacademy.com
  • 43. Palate  Secondary Palate – Nasal septum develops from downgrowths of merged medial nasal prominences – Fusion between nasal septum and palatine processes proceeds anteriorly to posteriorly www.indiandentalacademy.com
  • 44. Palate  Secondary Palate – Bone develops in primary palate forming the premaxillary part of the maxilla which lodges between the incisor teeth – Bone extends from the maxillae and palatine bones in to the lateral palatine processes to form the hard palate www.indiandentalacademy.com
  • 45. Palate  Secondary Palate – Posterior aspects do not ossify – Extend posteriorly beyond nasal septum and fuse to form the soft palate and uvula – Palatine raphe permanently indicates the line of fusion of the lateral palatine processes www.indiandentalacademy.com
  • 46. Palate  Secondary Palate – Small nasopalatine canal persists between premaxilla and palatine processes as incisive foramen (openings for incisive canals) www.indiandentalacademy.com
  • 47. Clefts – Lip and palate • Upper lip and anterior maxilla with or without hard and soft palate • Hard and soft palate – Complete posterior (to incisive foramen) palate – Anterior cleft anomalies • Cleft lip, with or without a cleft of the alveolar part of the maxilla • Result from deficiency of mesenchyme in the maxillary prominences and intermaxillary segment www.indiandentalacademy.com
  • 48. Clefts  Posterior cleft anomalies – Clefts of secondary or posterior palate that extend through the soft and hard palate to the incisive foramen – Caused by defective development of the secondary palate and result from the growth distortions of the lateral palatine processes (shelves) which prevent their medial migration and fusion www.indiandentalacademy.com
  • 49. Clefts – Lip • 1:1000 births, 70% male, • Caucasion>Asian>Hispanic>AA • Notches on vermilion border to alveolar maxilla www.indiandentalacademy.com
  • 50. Clefts – Unilateral • Failure of maxillary prominence on affected side to unite with merged medial nasal prominences • Consequence of failure of mesenchymal masses to merge and the mesenchyme to proliferate and smooth out the overlying epithelium • Results in persistent labial groove • Epithelium in the labial groove stretches and tissues of the floor breakdown • Lip is divided into medial and lateral parts • Bridge of tissue (Simonart’s band) joins parts of incomplete cleft lip www.indiandentalacademy.com
  • 51. Unilateral cleft lip www.indiandentalacademy.com
  • 52. Clefts – Bilateral • Failure of mesenchymal masses in the maxillary prominences to met and unite with the merged medial nasal prominences • Epithelium in both labial grooves becomes stretched and breaks down • May have varying degrees of defects on each side • When there is a complete bilateral cleft of the lip and alveolar part of the maxilla, the intermaxillary segment hangs free and projects anteriorly • These defects are deforming because of loss of continuity with the orbicularis oris muscle which purses the lips www.indiandentalacademy.com
  • 53. Clefts – Median (rare) • Upper – Mesenchymal deficiency causing partial or complete failure of medial nasal prominences to merge and form the intermaxillary segment – Characteristic of the Mohr syndrome • Lower – Failure of mesenchymal masses in the mandibular prominences to merge completely and smooth out the embryonic cleft between them www.indiandentalacademy.com
  • 54. Clefts – Palate • +/- lip in 1:2500 births, females • Uvula, soft/hard palate, lip, alveolar maxilla • Failure of mesenchymal masses in lateral palatine processes (shelves) to fuse with each other, the nasal septum and posterior margin of the median palatine process www.indiandentalacademy.com
  • 55. Clefts – Palate (divided by incisive foramen) • Anterior – Failure of mesenchymal masses in lateral palatine masses to fuse with primary palate • Posterior – Failure of mesenchymal masses in lateral palatine masses to fuse with nasal septum • Both – Failure of mesenchymal masses in lateral palatine masses to fuse with each other, primary palate or nasal septum www.indiandentalacademy.com
  • 56. Craniofacial clefts  1.4-5.1:100,000  Numbered 0-14 (sum=14) – 0-7 are facial – 8-14 are cranial  Number 7 is least rare (1:5600) =hemifacial microsomia (hypoplasia of mandibular ramus, hypoplasia of midface, others) associated with Goldenhar syndrome  Bilateral 6,7,8 is complete form of Treacher-Collins www.indiandentalacademy.com
  • 57. Others Facial clefts Macrostomia Microstomia Nasal Single nostril Bifid nose Absence www.indiandentalacademy.com
  • 58. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com