Head and Neck: Pharyngeal Apparatus Flashcards
Where do neural crests migrate
Into pharyngeal arches
What makes up the pharyngeal apparatus
Pharyngeal arch, pouch and cleft and membranes
What does each arch contain?
Cranial Nerve
Aortic arch artery
Cartilage
What is the pharyngeal cleft/groove?
Invagination of the ectoderm
Pharyngeal pouch?
outpocketings of endoderm
How do flat bones of face and skull form?
Intramembranous ossification
What is housed in the mesenchymal core of each arch?
Neural crest cells
Paraxial mesoderm
Lateral plate mesoderm
1st pharyngeal arch
Mandibular arch; largest
What 2 prominences make up the 1st pharyngeal arch
Maxillary prominence
Mandibular prominence
Does the maxillary or mandibular cartilage component remain in the adult?
The maxillary cartilage regresses (palatopterygoquadrate)
Mandibular -meckel’s cartilage remains
Meckel’s cartilage derivatives in adult (mandibular prominence)
Incus
Malleus
*** bone develops by endochondral ossification (cartilage model first)
Perichondrium of Meckel’s cartilage derivatives
Anterior ligament of malleus
Sphenomandibular ligament
Maxillary prominence derivatives
Maxillary bone
Zygomatic bone
Palatine bone
Squamous portions of temporal bone
**formed by intramembranous ossification
Mandibular prominence derivatives
by intramembranous ossification - mandible
Muscles derived from pharyngeal arch 1
Masticatory muscles: Temporalis, Masseter, Medial and Lateral Pterygoids Tensor Veli Palatini Tensor Tympani Ant. belly Digastric Mylohyoid
Cranial nerve of Arch 1
CN V - sensory to face and motor to muscles of arch 1
Skeletal components derived from cartilage of Arch 2 - Reichert’s cartilage
Stapes
Styloid process (endochondral ossification)
Stylohyoid ligament (perichondrium derived)
Lesser horn and upper body of hyoid
Muscles derived from Arch 2
All muscles of Facial Expression
Stapedius
Stylohyoid
Posterior belly of digastric
Cranial nerve of Arch 2
Facial Nerve CNVII
Innervation of Ant. Digastric
Comes from Arch 1 - so V
Innervation of Post. Digastric
Comes from Arch 2 - so VII
Skeletal component of 3rd Arch
Greater horn and lower half of body of hyoid bone
**remember lesser horn and upper half of hyoid bone body came from 2nd arch
Muscle component of 3rd arch
STYLOPHARYNGEUS
Cranial nerve of 3rd arch
CN IX -glossopharyngeal nerve
Skeletal component of arches 4/6
Laryngeal cartilages
*thought to come from lateral plate mesoderm
Muscular component of arches 4/6
soft palate
Soft palate: Levator veli palatini Uvulae Palatoglossus Palatopharyngeus
Muscular component of arches 4/6
Pharynx
Superior, middle and inferior constrictors
Palatopharyngeus
Salpingopharyngeus
Muscular component of arches 4/6
Larynx
Cricothyroid Thyroarytenoid Posterior crico-arytenoid Lateral crico-arytenoid Transverse and oblique arytenoids Vocalis
Cranial nerve of Arches 4/6
Vagus Nerve CN X
Arch Artery 1
Maxillary artery
Arch Artery 2
Stapedial artery
Hyoid Artery
Arch Artery 3
MAJOR: Common carotid , ECA and proximal part of ICA
Arch Artery 4
Left -arch of aorta + l. subclavian
Right - proximal r. subclavian
Arch Artery 6
Ductus arteriosus
Pulmonary arteries
Pharyngeal Pouch
associated with endoderm
Pharyngeal Pouch 1
Tubotympanic recess
*epithelial lining of tympanic cavity and Eustachian tube
Pharyngeal Pouch 2
Epithelium of palatine tonsil
Pharyngeal Cleft 1
epithelial lining of External acoustic meatus
Pharyngeal Pouch 3
complicated by developing a dorsal and ventral region
dorsal: Inferior parathyroid gland
Ventral: Thymus (stroma)
Pharyngeal Pouch 4
Dorsal: Superior parathyroid gland
Ventral: Ultimobranchial body -> parafollicular cells
Pharyngeal membrane
Tympanic membrane
Tongue is derived from which primordial tissue
Endoderm
Anterior 2/3 of tongue comes from which pharyngeal arch
Arch 1
Arch 1 contributions to tongue formation
2 lateral swellings and 1 median lingual swelling
**Lateral swellings overgrow and fuse in midline to cover the median bud
Dividing line between anterior and posterior tongue
Terminal sulcus
Which arches contribute to posterior 1/3 of tongue?
Root of tongue is formed by third/fourth arches
Anterior 2/3 of tongue innervated by which nerve
GSA: CN V
SA (taste): CN VII
Posterior 1/3 of tongue innervated by which nerve(s)
GSA and SA(taste):
Arch 3- CN IX -glossopharyngeal
Arch 4 - CN X
All muscles of tongue receive innervation from which cranial nerve?
CN XII - hypoglossal nerve
**except palatoglossus
Thyroid gland is derived from which primordial tissue type
Begins as a thickening of endoderm (diverticula)
What connects the foramen cecum in tongue to thyroid gland
The thyroglossal duct
Follicular vs. Parafollicular cells of thyroid origin
Follicular cells come from endoderm (thyroid)
Parafollicular cells (parathyroid) come from ultimobranchial body off of 4th pharyngeal pouch
Branchial cysts/fistulas
remnants of the cervical sinus which typically regresses
**typically found on anterior border of SCM
Thyroglossal cyst
remnant of thyroglossal duct between tongue and thyroid gland; always midline; sinus or fistula
First Arch Syndrome
abnormal development of first arch;
Treacher Collins Syndrom
Robin Sequence
Treacher Collins Syndrome
hypoplasia of zygomatic bone; mandibular hypoplasia
Robin Sequence
Triad complex:
poor growth of mandible causes
high, posteriorly placed tongue
prevents palatine shelves fusion = cleft palate
DiGeorge Syndrome
failure of 3rd/4th pharyngeal pouch differentiation
= thymus hypoplasia
absence of parathyroid glands (calcium regulation problems)
Borders of the stomadeum
Upper border: Frontonasal placod
Lateral borders: 2 maxillary prominences
Caudal border: 2 mandibular prominences
Nasal placode
thickening of surface ectoderm; mark site of future nasal cavities
Nasal placode = olfactory placode undergoes what changes?
Invaginates to form nasal pit
What structures surround the nasal pits?
Medial and Lateral nasal prominences surround the nasal pit derived from nasal placode
What structure separates the lateral nasal prominence from adjacent maxillary prominence?
Nasolacrimal groove!
What does the nasolacrimal groove become?
Nasolacrimal duct connect medial corner of eye to inferior meatus
Which nasal prominences fuse in the midline?
Medial nasal prominences fuse to give rise to intermaxillary segment
What (3) structures does the intermaxillary segment give rise to?
Philtrum of lip
Upper jaw - four incisors = premaxilla
Primary palate
By what mechanism does bone develop in all of hard palate
Intramembranous ossification
