Tuesday, 4-5-Embryology Of The Head And Neck (Stephens)

Question 1

List the membranous viscerocranium:

Answer 1

• Maxillary prominences of 1st branchial arch

- Mandibular prominence of 1st branchial arch

Question 2

___ is a premature fusion of coronal sutures and these pts tend to have a acrocephalic (“lower skull”) appearance

Answer 2

Apert syndrome

Question 3

___ represents the failure of the occipital and parietal bones to completely form or fuse. It is usually associated with arrested brain development and rudimentary forebrain (anacephaly)

Answer 3

Cranischisis

Question 4

___ is a small cranium due to early fusion of the cranial sutures.

Answer 4

Microcephaly

Question 5

___ is an enlarged cranium secondary to hydrocephaly.

Answer 5

Macrocephaly

Question 6

The facial swellings include:

Answer 6

• Frontal (frontonasal) prominence (unpaired)
• Maxillary prominences of Arch 1
• Mandibular prominences of Arch 1

Question 7

The __ prominence will form the forehead and the dorsum of the apex of the nose. A portion of the skin ectoderm in this region thickens to form nasal placodes.

Answer 7

Frontal (frontonasal)

Question 8

When does development of the face occur?

Answer 8

Weeks 5-10

Question 9

A ___ is due to the failure of the lateral nasal prominences and the maxillary prominences to fuse. It is often associated with cleft chin and a partial fusion of the mandibular prominences

Answer 9

Oblique facial cleft

Question 10

List the CN associated with the following branchial arches:

Arch I= ___ nerve
Arch 2=___ nerve
Arch 3=___ nerve
Arch 4=___ nerve

Answer 10

1=trigeminal
2-facial
3-glossopharyngeal
4=vagus

Question 11

Mesenchyme from Arch II invades into the maxillary and mandibular swellings (Arch I) and form the muscles of facial expression. The mimetic muscles are innervated by SVE fibers from the ___ nerve

Answer 11

VII

Question 12

Muscles of mastication are derived from the mesenchyme of Arch ___

Answer 12

I

Question 13

The muscles of mastication derived from Arch I are innervated by SVE fibers from the ___

Answer 13

V3

Question 14

By day 24, which arches are formed?

By day 27, which arches are formed?

By day 31, which arches are formed?

Answer 14

I and II

I, II, and III. Arch 1 divided into maxillary and mandibular swellings

All pharyngeal arches are formed and there is corresponding development of pharyngeal pouches

Question 15

Mandibular prominences are usually fused during the 4th week. They form the ___

Answer 15

Lower jaw and lip

Question 16

If there is partial or incomplete fusion of the mandibular prominences, a ___ will result

Answer 16

Cleft chin

Question 17

The nasal placodes invaginate to form the __. These expand dorsocaudally to form the nasal sacs. These sacs are the __ cavities and the partition between the 2 sacs is the nasal septum

Answer 17

Nasal pits

Primitive nasal

Question 18

In development of the nasal cavity:

__ deepen to form primitive nasal cavity

___ fuse as intermaxillary process

The intermaxillary process forms the __ and ___

Answer 18

Nasal pits

Medial nasal prominences

Nasal septum and primary palate

Question 19

The formation of the palate occurs between weeks ___

Answer 19

5-12

Question 20

The ___ marks the boundary between the junction of the primary and secondary palates. It also distinguishes anterior from posterior cleft deformities

Answer 20

Incisive foramen

Question 21

The primary palate includes ___

The secondary palate includes ___

Answer 21

• premaxillary and 4 upper incisors

- hard and soft palates

Question 22

An __ deformity results from a failure of the medial nasal and maxillary swellings to fuse.

Answer 22

Anterior cleft

Question 23

If the palatine shelves do not fuse during development, a ___ deformity results

Answer 23

Posterior cleft

Question 24

___ is a failure of the maxillary swelling to merge with its corresponding lateral nasal swelling. As a result, the nasolacrimal duct is exposed

Answer 24

Oblique facial cleft

Question 25

__ is a failure of the medial nasal prominences to fuse. It is rare and may be associated with an autosomal recessive

Answer 25

Median cleft lip and bifid nose

Question 26

___ is dyfusion of the maxillary and mandibular swellings

Answer 26

Macrostomia and microstomia

Question 27

In humans, the 1st, 2nd, 3rd, 4th, and 6th arches form during week 4 under the induction of migrating __ cells

Answer 27

Neural crest

Question 28

Regarding branchial arch nerves:

GSA fibers are sensory to __ structures such as skin

GVA fibers are sensory to __ structures such as the pharyngeal mucosa

SVE fibers are motor to __ of branchiomeric origin

Answer 28

Ectodermal

Visceral (endodermal)

Skeletal muscles

Question 29

List the major component for Arch I:

Muscle: ___

Nerve: ___

Skeletal structure: ___

Artery: ___

Branchial groove: ___

Answer 29

Mastication, anterior digastric, tensor tympani, tensor palati

CN V

Incus, malleus

Degenerates

Tympanic membrane, external auditory meatus

Question 30

List the components of Arch II:

Muscle: ___

Nerve: ___

Skeletal structure: ___

Artery: ___

Answer 30

Mimetic muscles, posterior digastric, stapedius, stylohyoid

CN VII

Stapes, lesser cornu of hyoid

Degenerates

Question 31

List the component of Arch III:

Muscle: ___

Nerve: ___

Skeletal structure: ___

Artery:

Answer 31

Stylopharyngeus

CN IX

Hyoid (body and greater cornu)

Stem of internal carotids

Question 32

List the components of Arch IV:

Muscle: ___

Nerve: ___

Skeletal structure: ___

Artery: ___

Answer 32

Pharyngeal and laryngeal mm.

CN X

Laryngeal cartilages

Left=Aortic arch, Right=subclavian

Question 33

Treacher collins syndrome is a ___ arch syndrome

Answer 33

1st

Question 34

This 1st arch syndrome is characterized by impaired growth of the midface. Deformities may include a small chin, enlarged nose, cleft palate, and possibly cleft lip. About 40-50% of these individual experience some conductive hearing loss due to underdevelopment of ossicles and usually affects the hearing in both ears equally.

Answer 34

Treacher collins syndrome

Question 35

The primitive pharynx is formed by rostral dilation of the ___ and develops from 4 pairs of lateral diverticulae called ___

Answer 35

Foregut

Pharyngeal pouches

Question 36

List 1st branchial pouch derivatives:

Answer 36

Eustachian tube

Tympanic cavity

Question 37

List 2nd branchial pouch derivatives:

Answer 37

• Palatine tonsils

- root of tongue

Question 38

List 3rd branchial pouch derivatives:

Answer 38

Inferior parathyroids

Thymus (ventral)

Tongue

Question 39

List 4th branchial pouch derivatives:

Answer 39

• Superior parathyroids

- Ultimobranchial body

Question 40

___ cysts may form anterior to the ear (anomalous derivative of the 1st pharyngeal cleft)

___ cysts are located anterior to the SCM

Answer 40

Aural

Lateral cervical

Question 41

__ is the 1st gland to appear in development at 24 dpf. It forms as a midline thickening in the floor of the primitive pharynx just caudal to the median tongue bed

Answer 41

Thyroid gland

Question 42

Glandular tissue that persists along the midline (extending upward) on the thyroid is a ___

Answer 42

Pyramidal lobe

Question 43

Thyroglossal duct cysts and sinuses may develop from remnants of the early migration of the thyroglossal duct. Remnants may also include __ tissue

Answer 43

Ectoptic thyroid

Question 44

List the cartilaginous viscerocranium:

Answer 44

• 1st branchial arch cartilage (Meckel’s)
• 2nd brachial arch cartilage (Reichert’s)
• 3rd brachial arch cartilage
• 4th and 6th brachial arch cartilages