Head & Neck Embryology Flashcards
What are the components of the pharyngeal (brachial) apparatus?
- Pharyngeal arch
- Pharyngeal groove (clef)
- Pharyngeal pouch
- Pharyngeal membrane
What cells are found in pharyngeal arches?
Neural crest cells
Initially, pharyngeal arches are a core of ___ covered by ______
Initially, pharyngeal arches are a core of mesenchyme covered by ectoderm externally and endoderm internally
What are the components of each pharyngeal arch?
- Artery
- Bone (cartilaginous rod)
- Muscle
- Nerve
The artery of a pharyngeal arch is derived from…
truncus arteriosus
Do pharyngeal arches 1, 2, and 3 develop together or separately?
Separately
Cartilaginous portions of which pharyngeal arches will fuse?
Arches 4 and 6
Which pharyngeal arch regresses and has no derivatives?
Arch 5
What is included in the frontonasal prominence?
- Optic vesicles
- Forehead
- Stomodeum (primordial mouth)
- Nose (frontal and lateral nasal prominences)
The first pharyngeal arch is also known as…
mandibular arch
What is the bone/cartilage component of the first pharyngeal arch?
Meckel’s cartilage
first arch
The maxillary prominence and mandibular prominence are from mesoderm around…
Meckel’s cartilage
first arch
What will come of the maxillary prominence?
- Maxilla
- Zygomatic bone
- Squamous part of temporal bone
- Upper cheek regions and lip
first arch
What will come of the mandibular prominence?
- Mandible
- Chin, lower lip, cheek regions
first arch
What will come of the dorsal end?
- Malleus
- Incus
- Sphenomandibular ligament
What are five muscular components of the first pharyngeal arch?
- Muscles of mastication
- Tensor veli palatini
- Tensor tympani
- Mylohyoid
- Anterior belly of digastric
What is the nerve component of the first pharyngeal arch?
CN V trigeminal
The second pharyngeal arch is also known as…
hyoid arch
What is the bone/cartilage component of the second pharyngeal arch?
Reichert’s cartilage
second arch
What will come of Reichert’s cartilage?
- Stapes
- Styloid process
- Stylohyoid ligament
- Lesser cornu and upper part of body of hyoid
What are four muscular components of the second pharyngeal arch?
- Muscles of facial expression
- Stapedius
- Stylohyoid
- Posterior belly of digastric
What is the nerve component of the second pharyngeal arch?
CN VII facial
What would you call a persistent second pharyngeal groove or cervical sinus?
Branchial cyst
When is a branchial cyst apparent?
Beginning in late childhood or early adulthood
How does a branchial cyst appear?
Painless swollen mass slowly enlarging inferior to angle of mandible and anterior to SCM
Which pharyngeal arch does not develop into adult structures?
Arch 5
What are the bone/cartilage components of the third pharyngeal arch?
- Thyroid cartilage
- Hyoid bone (greater cornu and part of body)
What is the muscular component of the third pharyngeal arch?
Stylopharyngeus
What is the nerve component of the third pharyngeal arch?
CN IX glossopharyngeal
What is the bone/cartilage component of the fourth and sixth pharyngeal arches?
Laryngeal cartilages (except epiglottis)
The epiglottis develops from…
hypopharyngeal eminence
What is the muscular component of the fourth and sixth pharyngeal arches?
Pharyngeal and laryngeal muscles:
- Cricothyroid
- Levator veli palatini
- Pharyngeal constrictor muscles
What is the nerve component of the fourth and sixth pharyngeal arches?
CN X vagus
4: superior laryngeal nerve
6: recurrent laryngeal nerve
The tympanic cavity, mastoid antrum, pharyngotympanic tube, and tympanic membrane are all derived from which pharyngeal apparatus pouch?
First pouch