Head & Neck Dev. Flashcards Preview

Anatomy Exam 3 Blue Boxes > Head & Neck Dev. > Flashcards

Flashcards in Head & Neck Dev. Deck (73)
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1
Q

what is acrania?

A

complete or partial absence of neurocranium

2
Q

what is acrania associated with?

A

meroencephaly (causes acrania)

3
Q

what is craniosynostosis?

A

prenatal fusion of cranial sutures that results in defects in the neurocranium

4
Q

what is scaphocephaly?

A

premature closure of sagittal suture (long, narrow, wedge-shaped cranium)

5
Q

what is brachycephaly?

A

premature closure of coronal suture (tower like cranium)

6
Q

what is plagiocephaly?

A

premature closure of coronal suture on one side only (twisted and asymmetrical cranium)

7
Q

what is trigonocephaly?

A

premature closure of frontal suture

8
Q

what is microcephaly?

A

small calvaria

9
Q

what causes microcephaly?

A

abnormal brain development in which the brain fails to grow

10
Q

congenital anomalies of craniovertebral junction cause?

A
  • basilar invagination
  • assimilation of the atlas
  • atlantoaxial dislocation
  • arnold-chiari malformation
  • separated dens from axis
11
Q

how do external branchial sinuses form?

A

failure of second pharyngeal groove and cervical sinus to obliterate

12
Q

where does an external branchial sinus emerge?

A

anterior border of SCM (discharge of mucus)

13
Q

where do internal branchial sinuses open to?

A

tonsillar sinus or near palatopharyngeal arch (failure of 2nd pharyngeal pouch to disappear)

14
Q

normal remnant of 2nd pharyngeal pouch?

A

tonsillar sinus

15
Q

what is a branchial fistula?

A

abnormal canal that opens internally into tonsillar sinus and externally in the neck

16
Q

a branchial fistula passes through what structures?

A
  • platysma

- between internal and external carotid arteries

17
Q

what is a piriform sinus fistula?

A

persistance of remnants of “ultimopharyngeal” body along its path to thyroid gland

18
Q

what is a branchial cyst?

A

remnants of cervical sinus or 2nd pharyngeal groove

19
Q

where are branchial cysts most often located?

A

lie free in neck inferior to angle of mandible & anterior border of SCM; parathyroid glands

20
Q

what is a branchial vestige?

A

cartilagenous or bony remnants of pharyngeal arch cartilages under the skin on the side of the neck

21
Q

where are branchial vestiges located?

A

anterior to inferior third of SCM

22
Q

how does first arch syndrome occur?

A

insufficient migration of neural crest cells into first arch

23
Q

infants with DiGeorge syndrome are born without what structures?

A

thymus and parathyroid glands

24
Q

what is DiGeorge syndrome characterized by?

A
  • congenital hypoparathyroidism
  • lots of infections
  • cardiac anomalies
25
Q

why does DiGeorge syndrome occur?

A

third and forth pharyngeal pouches fail to differentiate into thymus and parathyroid glands

26
Q

how does an accessory thymus occur?

A

tissue breaks free from developing thymus as it shifts caudally in the neck

27
Q

where are ectopic sites for parathyroid glands?

A

inferiors can be near bifurcation of common carotid artery or in the thorax

28
Q

accessory parathyroid glands occurs because?

A

extra division of primordia of original glands

29
Q

absence of parathyroid glands occurs from?

A

failure of primordia to differentiate or from atrophy of a gland

30
Q

what is the most common metabolic disorder in neonates?

A

congenital hypothyroidism

31
Q

what can congenital hypothyroidism result in?

A

neurodevelopmental disorders and infertility if untreated

32
Q

how do thyroglossal duct cysts occur?

A

remnant of thryoglossal duct persists in tongue or inferior to hyoid bone

33
Q

how does a thryoglossal duct sinus occur?

A

infection of cyst leads to perforation of skin in median plane of neck

34
Q

where is an ectopic thyroid gland located?

A

along thyroglossal duct (most common is lingual area)

35
Q

why is it important to distinguish an ectopic thyroid gland from a thryoglossal duct cyst or accessory thyroid tissue?

A

to prevent accidental surgical removal of the thyroid

36
Q

what is thyroid hemiagenesis?

A

unilateral failure of formation of thyroid lobe (usually left lobe)

37
Q

what congenital tongue anomalies are associated with down’s syndrome?

A

fissuring of tongue and hypertrophy of lingual papillae

38
Q

cysts in the tongue come from where?

A

thyroglossal duct

39
Q

lingual cysts cause what?

A

pharyngeal discomfort and dysphagia

40
Q

where do lingual fistulas open to?

A

from thyroglossal duct to foramen cecum into oral cavity

41
Q

what is ankyloglossia?

A

short lingual frenulum that interferes with protrusion of tongue

42
Q

is surgery required to fix ankyloglossia?

A

no. normal stretching usually does the trick

43
Q

how does macroglossia occur?

A

generalized hypertrophy of developing tongue from lymphangioma (lymph tumor)

44
Q

what syndrome is macroglossia usually found in?

A

downs syndrome

45
Q

what is microglossia associated with?

A

micrognathia (underdeveloped mandible/recession of chin) and limb defects (Hanhart syndrome)

46
Q

what is glossoschisis?

A

bifid or cleft tongue (incomplete fusion of tongue)

47
Q

how does atresia of nasolacrimal duct occur?

A

failure of nasolacrimal duct to canalize

48
Q

when are maxillary sinuses fully developed?

A

when all permanent teeth have erupted (early adulthood)

49
Q

are frontal and sphenoid sinuses present at birth?

A

no

50
Q

what forms the frontal sinus?

A

anterior ethmoidal cells grow into frontal bone —> frontal sinus

51
Q

what forms the sphenoidal sinus?

A

posterior ethmoidal cells grow into sphenoid bone

52
Q

the growth of the paranasal sinuses are important for?

A

altering size and shape of face and adding resonance to voice

53
Q

how do anterior cleft anomalies occur?

A

deficiency of mesenchyme in maxillary prominences and median palantine process

54
Q

how do posterior cleft anomalies occur?

A

defective development of secondary plate and growth problems of lateral palantine processes (no fusion)

55
Q

what is a unilateral cleft lip?

A

failure of maxillary prominence on one side to unite with medial nasal prominence

56
Q

what causes a persistant labial groove?

A

failure of mesenchymal masses to merge and proliferate

57
Q

what is a simonart band?

A

bridge of tissue connecting incomplete unilateral cleft lip

58
Q

what is a bilateral cleft lip?

A

failure of mesenchymal masses in both maxillary prominences to unite with medial nasal prominences

59
Q

a bilateral cleft lip affects which muscle?

A

orbicularis oris

60
Q

what is a median cleft lip?

A

failure of medial nasal prominences to merge and form median palatal process

61
Q

median cleft of lower lip is caused by?

A

failure of mandibular prominences to merge

62
Q

what does a cleft uvula look like?

A

fishtail appearance

63
Q

what is a distinguishing landmark between anterior and posterior cleft anomalies?

A

incisive fossa

64
Q

clefts of primary/anterior palate?

A

failure of lateral palatal processes to fuse with primary palate

65
Q

clefts of secondary/posterior palate?

A

failure of lateral palatine processes to fuse with each other and nasal septum

66
Q

clefts of primary and secondary palate?

A

failure of lateral palatine processes to fuse in primary plate, with each other, and with the nasal septum

67
Q

cleft lip/palate are especially associated with which syndrome?

A

trisomy 13

68
Q

what is congenital microstomia?

A

small mouth

69
Q

why does congenital microstomia occur?

A

excess merging of mesenchymal masses in maxillary and mandibular prominences of first pharyngeal arch

70
Q

why would a single nostril form?

A

if only one nasal placode forms

71
Q

what’s a bifid nose?

A

medial nasal prominences don’t merge which causes nasal bridge to be bifid

72
Q

oblique facial clefts cause what?

A

nasolacrimal ducts to be open grooves

73
Q

bilateral facial clefts result in?

A

macrostomia