Pharyngeal arches Flashcards
masseter mm (medial pterygoid, lateral pterygoid, temporalis) Bones: maxilla and mandible
first pharyngeal arch - CN V2, V3
causes Pierre Robin sequence (micrognathia, glossoptosis, cleft palate, airway obstruction)
stylopharyngeus mm - innervated by CN IX (posterior 1/3 of tongue)
Bones: greater horn of hyoid
third pharyngeal arch
does not form adult structures
fifth pharyngeal arch
cricothyroid mm, intrinsic mm of soft palate (eg levator veli palatini - innervated by CN X)
Bones: cricoid and thyroid cartilages
fourth; 6th pharyngeal arch
mm of facial expression (buccinators, platysma, stapedius, stylohyoid, posterior belly of digastrics) - innervated by CN VII
Bones: stapes, styloid process, less horn of hyoid
second pharyngeal arch
anterior 2/3 of tongue
first and second pharyngeal arch
most mm of the tongue are innervated by CN XII except what?
Palatoglossus - innervated by CN X
thymus
third pharyngeal POUCH
22q11 (eg DiGeorge) is due to failure of which branchial pouches?
3rd and 4th
thymus and parathyroid not formed (T cell def and hypocalcemia respectively)
Aortic arch derivatives: stapedial artery and hyoid artery
2 (S for second and stapedial)
Aortic arch derivatives: Aortic arch, proximal part of R subclavian
4
Aortic arch derivatives: pulmonary arteries and ductus arteriosus
6
Aortic arch derivatives: Common carotid artery and proximal part of internal carotid
3 (C is 3rd letter of the alphabet)
Aortic arch derivatives: Maxillary artery (branch of external carotid)
1 (maximal)
Branchial Pouch: endoderm-lined structures of the ear
1
Branchial Pouch: Superior parathyroid, parafollicular C cells of thyroid
4
Note: if you can’t find a parathyroid when performing a parathyroidectomy, explore near the thymus bc thymus and parathyroid are both derivatives of the 4th pharyngeal pouch
Branchial Pouch: inferior parathyroids, thymus
3
Branchial Pouch: lining of palatine tonsil
2
mneumonic for branchial pouch derivatives
ear (1), tonsils (2), bottom (3)-to-top(4)
Treacher Collins syndrome is due to defect in what pharyngeal arch?
1
Neural crest dysfunction –.> mandibular hypoplasia, facial abnormalities
Genital embryology: What duct develops into the male internal structures
Mesonephric (Wolffian)
Genital embryology: What duct develops into the female internal structures
Paramesonephric (Mullerian) duct
Calcitonin-secreting cells develop in what part of the body during embryology?
ultimobranchial body and then migrate toward the midline into a parafollicular location in the thyroid gland.
