Embryology of Head and Neck - Acht/Glick Flashcards Preview

Neuro Block 3 > Embryology of Head and Neck - Acht/Glick > Flashcards

Flashcards in Embryology of Head and Neck - Acht/Glick Deck (30)
Loading flashcards...
1
Q

What are the 5 pharangeal arches?

A

1,2,3,4,6
They surround the foregut
Clefts = 1,2,3,4
4 pouches, evaginations covered in endoderm

2
Q

Motor innervation of muscles derived from the pharyngeal arches:

1,2,3,4,6

KNOW THIS!!!!!!!!!!!!!

A
1st arch muscles  - trigeminal nerve
2nd arch muscles - facial nerve
3rd arch muscles - glossopharyngeal n.
4th arch muscles - vagus nerve
6th arch muscles - vagus nerve
3
Q

Skeletal Derivatives of the First Arch?

A

Maxilla
Zygomatic
Squamous part of temporal bone
(Intramembranous ossification)

malleus, incus, pine of sphenoid

4
Q

Muscles and Nerve of the First Arch

A

“tense tense, chew chew”

Trigeminal - mandibular branch (V3) (SVE) innervates:

Muscles of mastication (temporalis, masseter)
Mylohyoid
Anterior belly of digastric
Tensor tympani
Tensor veli palatini
5
Q

Hallmark of Pierre Robin Syndrome

A

Large posterior tongue and airway obstruction

Genetic and/or environmental etiology.

Deficiency of neural crest cells migrating into the arch.

6
Q

Skeletal derivative of second arch (Reichert’s cartilage)

A

The stapes, stylpid process, stylohyoid ligament, upper part of hyoid bone

7
Q

Muscles and Nerve derivatives of the Second Arch?

A

Facial nerve (CN VII) (SVE) innervates:

Muscles of facial expression
Posterior belly of digastric
Stylohyoid
Stapedius

8
Q

Skeletal Derivatives of the Third Arch?

A

lower body of hyoid bone

9
Q

Muscle and Nerve of the Third Arch?

A

Glossopharyngeal nerve CN (IX) (SVE) innervates:

Stylopharyngeus

10
Q

Muscles and Nerves of the Fourth & Sixth Arches?

A

Fourth arch: Superior laryngeal branch of Vagus (CN X) (SVE) innervates:
Muscles of the soft palate (except tensor veli palatini)
Muscles of the pharynx (except stylopharyngeus)
Cricothyroid
Cricopharyngeus

Sixth arch: Recurrent laryngeal branch of Vagus (CN X) (SVE) innervates:
Intrinsic muscles of larynx (except cricothyroid)
Striated (upper) muscle of esophagus

11
Q

What does the 1st pharyngeal pouch form?

A

The tympotympanic recess

Will form auditory tube, middle ear cavity, mastoid air cells

12
Q

2nd pharayngeal puch will form?

A

Palatine tonsils

13
Q

Third pharyngeal puch will form?

A

Ventral part descend to form THYMUS

Dorsal part descend to form INFERIOR PARATHYRIOD

14
Q

Fourth Pharyngeal puch forms?

A

Superior parathyroid glands

Ultimobranchial body

15
Q

What is the problem with Accessory or ectopic parathyroids?

A

-Accessory or ectopic parathyroids: variable in # and location; Inferior may fail to descend or may be found in the thorax carried along with the thymus.

Bad if you have an adenoma and the surgeon can’t find the parathyroid glands

16
Q

What is DiGeorge Syndrome?

A

A microdeletion of Chromosoe 22
No thymus or parathyroids
Failure of neural crest migration into arches  3rd & 4th pouch failure & hypoplasia of 1st arch (cleft palate, low set ears, poor feeding, delayed speech)
Heart defects, poor circulation, poor muscle tone

17
Q

1st cleft becomes?

A

The external auditory meatus

18
Q

What happens to the 2nd, 3rd, and 4th clefts?

A

They are overgrown by the 2nd arch and leave a transitory CERVICAL SINUS

It disappears, if it doesn’t it will form a cervical cyst or fistula

19
Q

Where do the cells making up the thyroid gland come from?

A

Follicular cells of the thyroid gland come from the thyroid diverticulum

Prafollicular cells frome from the 4th pharyngeal pouch

20
Q

What is the sensory and motor input of the tongue?

A

SENSORY:
-Anterior tongue:
GSA lingual branch of V, mandibular division, i.e. the nerve of the first pharyngeal arch
SVA (taste) by chorda tympani part of VII

-Posterior tongue: GSA by IX and X
SVA (taste) by IX
–Epiglottis: GVA and SVA by X

MOTOR: tongue muscles from occipital somites/myotomes & innervated by XII – except for palatoglossus (X)

21
Q

Most common development problem leading to bcervical cyst?

A

2nd arch development problems

22
Q

In the case of a thryoglossal duct cyst, what is the surgery?

A

Excision of entire tract, cyst, and even the central portion of the hyoid bone

23
Q

What developmental cells make up a pharangeal arch?

A

Bars of mesenchyme, with a layer of external ectoderm and

24
Q

Neural crest cells stream into the developing pharyngeal arches to form what?

A

Skeletal elements (bones, ligaments, cartilage) of the head

25
Q

What is the syndrome attributed to neural cells not migrating into the first neural arch causing Mandibulofacial dysostosis?
Hallmarks?

A

Treacher-Collins Syndrome

Hypoplasia of upper & lower jaw; external & middle ear deformities, palate & eyelid defects
Conductive hearing loss

26
Q

Which pharyngeal membrane persists?

A

The 1st membrane is the only one that persists - becomes the tympanic membrane

27
Q

What is anyloglossia?

How do you correct it?

A

The frenulum is TOO attached

Basically just cut it to get immediate good results

28
Q

What is an otoplasty correcting for?

A

Cosmetic surgery for ears that stick out

Basically you are creating an antihelical fold OR removing excess cartilage causing this to occur

29
Q

Why is choanal atresia important to correct in infants?

A

Babies must be able to breathe through their nose to breas/bottle feed. Choanal atresia is basically an obstruction of this air passage which makes life for a baby miserable until it’s fixed

30
Q

Why are cleft lip and cleft palate not always together?

A

Lips and palate are formed at weeks 7 and 9 respectively. So they can be independent of each other