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

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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

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

    • Head and Neck Embryology INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
    • 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
    • Branchial and Pharyngeal Arches  First = Mandibular – Mandibular Prominence  jaw – Maxillary Prominence  maxilla/zyg/temp  Second = Hyoid www.indiandentalacademy.com
    • www.indiandentalacademy.com
    • Branchial and Pharyngeal Arches  Fate – Typical arch contains • Aortic arch • Cartilaginous rod (skeleton of arch) • Muscular component • Nerve www.indiandentalacademy.com
    • Branchial and Pharyngeal Arches www.indiandentalacademy.com
    • 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
    • Pharyngeal Pouches  Fourth – Superior parathyroid gland – Ultimobranchial body fuses with thyroid – Parafollicular C cells  calcitonin  Fifth – Rudimentary www.indiandentalacademy.com
    • www.indiandentalacademy.com
    • Pharyngeal Pouches www.indiandentalacademy.com
    • 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
    • Branchial or Pharyngeal Grooves www.indiandentalacademy.com
    • Branchial or Pharyngeal Membranes  Only one pair contribute to adult structures  First  tympanic membrane www.indiandentalacademy.com
    • 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
    • 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
    • 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
    • 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
    • Branchial and Pharyngeal Anomalies  Branchial Vestiges – Cartilaginous or bony remnants – Usually anterior to inferior third of sternocleidomastoid www.indiandentalacademy.com
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • Tongue  Taste buds – Most are filiform papillae and are sensitive to touch www.indiandentalacademy.com
    • 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
    • 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
    • Ear www.indiandentalacademy.com
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • Palate  Secondary Palate – Small nasopalatine canal persists between premaxilla and palatine processes as incisive foramen (openings for incisive canals) www.indiandentalacademy.com
    • 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
    • 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
    • Clefts – Lip • 1:1000 births, 70% male, • Caucasion>Asian>Hispanic>AA • Notches on vermilion border to alveolar maxilla www.indiandentalacademy.com
    • 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
    • Unilateral cleft lip www.indiandentalacademy.com
    • 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
    • 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
    • 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
    • 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
    • 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
    • Others Facial clefts Macrostomia Microstomia Nasal Single nostril Bifid nose Absence www.indiandentalacademy.com
    • Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com