Pharyngeal arches and derivatives

Question 1

Arch 1

Answer 1

: Treacher Collins syndrome - no first pharyngeal arch - mandibular hypoplasia, facial abnormalities

Muscles and bones of mastication

• Masseter, temporalis, medial pterygoid, lateral pterygoid (opens mouth)
• Maxilla, Mandible

+

Malleus, Incus

+

Trigeminal nerve

https://web.duke.edu/anatomy/embryology/craniofacial/craniofacial.html

Question 2

Arch 2

Answer 2

CN7, Stapedial artery

Styloid + Hyoid (lesser horn), Stapes

• Usually obliterates the clefts. If not –> Brachial cleft cyst anterior to SCM
  https: //web.duke.edu/anatomy/embryology/craniofacial/craniofacial.html

Question 3

Arch 3

Answer 3

CN9, Internal carotid, Stylopharyngeus muscle, Hyoid (greater horn)

Question 4

Arch 4

Answer 4

Superior laryngeal nerve, Cricoithyroid cartilage, aortic arch/subclavians

Question 5

Arch 6

Answer 5

Recurrent laryngeal nerve, PDA

Question 6

3/4 pharyngeal pouch

Answer 6

3 - inferior parathyroid + thymus
4 - superior parathyroid

Di-George