Embryology (Head and Neck) Flashcards
What are the five pharyngeal arches and what CN is associated with each?
- Arch 1: Trigeminal (CN V)
- Arch 2: Facial (CN VII)
- Arch 3: Glossopharyngeal (IX)
- Arch 4: Vagus (X)
- Arch 6: Vagus (X)
Cartilage of the second pharyngeal arch becomes a part of which four structures?
- Part of body and lesser horn of Hyoid bone
- Styloid process
- Stylohyoid ligament
- Stapes
What are the four muscles/muscle groups that are derived from the second arch? What CN are these muscles innervated by?
- Stylohyoid
- Posterior belly of Digastric
- Stapedius
- Muscles of facial expression
ALL are innervated by CN VII
Swellings from the floor of the developing pharynx contribute to the development of what body structure?
Tongue
Which two swellings come from arch 1? What is the innervation of this arch and what does this nerve contribute to later in life (hint: think nerve fiber type)
Lateral lingual swellings and Tuberculum impar both come from arch 1
- Arch 1: innervated by CN V so contributes to the sensation of the anterior 2/3 of tongue
Which swelling comes from arch 2, 3 and 4? What are the innervations of these arches and what do these nerves contribute to later in life (hint: think nerve fiber type)
Copular comes from arches 2, 3 and 4
- Arch 2: innervated by CN VII so contributes to taste of the anterior 2/3 of tongue
- Arch 3: innervated by CN IX so contributes to both sensation and taste of posterior 1/3 of tongue
- Arch 4: innervated by CN X so contributes to both sensation and taste of posterior 1/3 of tongue
What other swelling comes from arch 4? What is the innervation of this arch and what does this nerve contribute to later in life (hint: think nerve fiber type)
Epiglottal swelling comes from arch 4
- Arch 4: innervated by CN X so contributes to both sensation and taste of posterior 1/3 of tongue
Which of the four arches is initially involved in tongue development but eventually disappears? Which arch is the swelling of this arch incorporated into?
Arch 2 disappears and its swelling is incorporated into Arch 1 (BUT nerve fibers from CN VII are carried with it, hence why both nerves contribute to the anterior 2/3 of the tongue)