Head & Neck Flashcards
How many pairs of pharyngeal arches exist in the pharyngeal apparatus?
5
Which pharnyngeal arch regresses before completing development?
the 5th pharyngeal arch
How many clefts exist within the pharyngeal apparatus?
3
How many pouches exist within the pharyngeal apparatus?
4 or 5
What two structures compose the membrane (closing plates) of the pharyngeal apparatus?
clefts and pouches
Arch 1 contains which muscular components?
muscles of mastication
Arch 2 contains which muscular components?
muscles of facial expression
Arch 3 contains which muscular components?
Stylopharyngeus
Arch 4 contains which muscular components?
Pharyngeal constrictors and palatal muscles
Arch 6 contains which muscular componets?
all laryngeal muscles except for the cricothyroid
Which vessels does aortic arch 1 develop into?
The maxillary and external carotid arteries
Which vessels does aortic arch 2 develop into?
The stapedial and hyoid arteries
Which vessels does aortic arch 3 develop into?
The common and internal carotid arteries
Which structures arise from aortic arch 4?
The adult aortic arch and the subclavian artery
Which structures are formed from aortic arch 6?
The pulmonary arteries and ductus arteriosus
Meckel’s cartilage refers to cartilaginous components of which arch?
arch 1
What are the cartilaginous components of arch 1?
maxilla, mandible, temporal bone, as well as the malleus and the incus
Reichert’s cartilage refers to the cartilaginous components of which arch?
arch 2
What are the cartilaginous components of arch 2?
styloid process, stylohyoid ligament, lesser horn and body of hyoid bone, as well as stapes
What are the cartilaginous components of arch 3?
greater horn and body of hyoid bone
What are the cartilaginous components of arch 4?
thyroid and cricoid cartilages
What are the cartilaginous components of arch 6?
arytenoid cartilages
Which arch(es) does the trigeminal nerve innervate?
arch 1 (mastication)
Which arch(es) does the facial nerve innervate?
arch 2 (facial expression)
Which arch(es) does the glossopharyngeal nerve innervate?
arch 3 (stylopharyngeus)
Which arch(es) does the vagus nerve innervate?
arches 4 (pharynx) and 6 (larynx)
In the event of deactivation/loss of Hox genes, how are pharyngeal arches impacted?
Neural crest cells fail to migrate, and all arches develop as pharyngeal arch 1
Which arch forms the anterior 2/3 of the tongue epithelium?
arch 1
Which arch forms the remaining 1/3 of tongue epithelium?
arch 3
Which arch forms the midline swelling of the tongue (copula), but is covered by arch 3 derivatives as it grows?
arch 2
Which arch forms the small portion of tongue at the back of the throat?
arch 4
What gives rise to the muscles of the tongue?
occpital somites that migrate to the level of the tongue
which pharyngeal cleft is the only cleft not obliterated in normal in development?
cleft 1
what does pharyngeal cleft 1 give rise to?
external auditory meatus and part of tympanic membrane
Which pharyngeal pouch gives rise to the lining of the crypts in palatine tonsils?
pharyngeal pouch 2
Which pharyngeal pouch gives rise to the tympanic membrane and cavity (distal) as well as the eustachian tube (proximal)?
pharyngeal pouch 1
What does the fourth pharyngeal pouch give rise to?
dorsal wing- superior parathyroid glands
ventral wing- ultimobranchial body (contains C cells of thyroid)
What does the third pharyngeal pouch give rise to?
dorsal wing- inferior parathyroid glands
ventral wing- thymus
What is craniosynostosis?
the premature fusion of skull sutures
What are signs/symptoms of Apert syndrome?
craniosynostosis, midface hypoplasia, hypertelorism, syndactyly of hands and feet, and hearing loss
Apert syndrome typically involves a mutation in what gene?
FGFR2
What is the difference between a syndrome and a sequence?
a syndrome denotes a combination of various abnormalities, while a sequence indicates a linear chain of abnormalities usually with a causal relationship (A -> B -> C -> D)
What are the signs/symptoms of a thyroglossal duct cyst?
usually asymptomatic; but if infected may present with swelling and pus
When do the maxillary processes fuse during palate formation?
They do not fuse
Which branch of the vagus nerve innervates arch 4?
the superior laryngeal nerve and pharyngeal branch of vagus
Which branch of the vagus nerve innervates arch 6?
the recurrent laryngeal nerve
A cleft palate resulting from a failure to fuse involving the primary plate (intermaxillary segment) is found in what area of the palate?
anterior
A cleft palate resulting from a failure to fuse involving the secondary plate (palatal shelves) is found in what area of the palate?
posterior
What separates the oral cavity from the developing nasal sac?
the oronasal membrane?
After the oronasal membrane ruptures, what develops to separate the oral and nasal cavities?
the secondary palate
Which palate develops from the median nasal process?
the primary palate
Where would a branchial cleft cyst be most likely to be found?
along the anterior border of the sternocleidomastoid
Where would a thyroglossal duct cyst be most likely to be found?
between the thyroid and the tongue along the trachea
What malformation most likely results in a cleft lip through the midline of the upper lip (philtrum)?
failure of two medial nasal prominences to fuse
