Tuesday, 4-5-Embryology Of The Head And Neck (Stephens) Flashcards
List the membranous viscerocranium:
- Maxillary prominences of 1st branchial arch
- Mandibular prominence of 1st branchial arch
___ is a premature fusion of coronal sutures and these pts tend to have a acrocephalic (“lower skull”) appearance
Apert syndrome
___ 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)
Cranischisis
___ is a small cranium due to early fusion of the cranial sutures.
Microcephaly
___ is an enlarged cranium secondary to hydrocephaly.
Macrocephaly
The facial swellings include:
- Frontal (frontonasal) prominence (unpaired)
- Maxillary prominences of Arch 1
- Mandibular prominences of Arch 1
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.
Frontal (frontonasal)
When does development of the face occur?
Weeks 5-10
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
Oblique facial cleft
List the CN associated with the following branchial arches:
Arch I= ___ nerve
Arch 2=___ nerve
Arch 3=___ nerve
Arch 4=___ nerve
1=trigeminal
2-facial
3-glossopharyngeal
4=vagus
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
VII
Muscles of mastication are derived from the mesenchyme of Arch ___
I
The muscles of mastication derived from Arch I are innervated by SVE fibers from the ___
V3
By day 24, which arches are formed?
By day 27, which arches are formed?
By day 31, which arches are formed?
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
Mandibular prominences are usually fused during the 4th week. They form the ___
Lower jaw and lip
If there is partial or incomplete fusion of the mandibular prominences, a ___ will result
Cleft chin
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
Nasal pits
Primitive nasal
In development of the nasal cavity:
__ deepen to form primitive nasal cavity
___ fuse as intermaxillary process
The intermaxillary process forms the __ and ___
Nasal pits
Medial nasal prominences
Nasal septum and primary palate
The formation of the palate occurs between weeks ___
5-12
The ___ marks the boundary between the junction of the primary and secondary palates. It also distinguishes anterior from posterior cleft deformities
Incisive foramen
The primary palate includes ___
The secondary palate includes ___
- premaxillary and 4 upper incisors
- hard and soft palates
An __ deformity results from a failure of the medial nasal and maxillary swellings to fuse.
Anterior cleft
If the palatine shelves do not fuse during development, a ___ deformity results
Posterior cleft
___ is a failure of the maxillary swelling to merge with its corresponding lateral nasal swelling. As a result, the nasolacrimal duct is exposed
Oblique facial cleft
__ is a failure of the medial nasal prominences to fuse. It is rare and may be associated with an autosomal recessive
Median cleft lip and bifid nose
___ is dyfusion of the maxillary and mandibular swellings
Macrostomia and microstomia
In humans, the 1st, 2nd, 3rd, 4th, and 6th arches form during week 4 under the induction of migrating __ cells
Neural crest
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
Ectodermal
Visceral (endodermal)
Skeletal muscles
List the major component for Arch I:
Muscle: ___
Nerve: ___
Skeletal structure: ___
Artery: ___
Branchial groove: ___
Mastication, anterior digastric, tensor tympani, tensor palati
CN V
Incus, malleus
Degenerates
Tympanic membrane, external auditory meatus
List the components of Arch II:
Muscle: ___
Nerve: ___
Skeletal structure: ___
Artery: ___
Mimetic muscles, posterior digastric, stapedius, stylohyoid
CN VII
Stapes, lesser cornu of hyoid
Degenerates
List the component of Arch III:
Muscle: ___
Nerve: ___
Skeletal structure: ___
Artery:
Stylopharyngeus
CN IX
Hyoid (body and greater cornu)
Stem of internal carotids
List the components of Arch IV:
Muscle: ___
Nerve: ___
Skeletal structure: ___
Artery: ___
Pharyngeal and laryngeal mm.
CN X
Laryngeal cartilages
Left=Aortic arch, Right=subclavian
Treacher collins syndrome is a ___ arch syndrome
1st
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.
Treacher collins syndrome
The primitive pharynx is formed by rostral dilation of the ___ and develops from 4 pairs of lateral diverticulae called ___
Foregut
Pharyngeal pouches
List 1st branchial pouch derivatives:
Eustachian tube
Tympanic cavity
List 2nd branchial pouch derivatives:
- Palatine tonsils
- root of tongue
List 3rd branchial pouch derivatives:
Inferior parathyroids
Thymus (ventral)
Tongue
List 4th branchial pouch derivatives:
- Superior parathyroids
- Ultimobranchial body
___ cysts may form anterior to the ear (anomalous derivative of the 1st pharyngeal cleft)
___ cysts are located anterior to the SCM
Aural
Lateral cervical
__ 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
Thyroid gland
Glandular tissue that persists along the midline (extending upward) on the thyroid is a ___
Pyramidal lobe
Thyroglossal duct cysts and sinuses may develop from remnants of the early migration of the thyroglossal duct. Remnants may also include __ tissue
Ectoptic thyroid
List the cartilaginous viscerocranium:
- 1st branchial arch cartilage (Meckel’s)
- 2nd brachial arch cartilage (Reichert’s)
- 3rd brachial arch cartilage
- 4th and 6th brachial arch cartilages
