Formation of Face - Weeks 3-5 Flashcards
What is the crown-rump length in the 3rd week?
3mm
What is the crown-rump length in the 8th week?
30mm
The ____ appears in the 3rd week and becomes the nasal and oral cavities between the 6th and 8th weeks.
Stomodeum
What are the 3 boundaries of the stomodeum?
Superior - Frontal prominence
Inferior - Cardiac plate
Posterior - Buccopharyngeal membrane
In week 4, the first branchial arch becomes what?
R and L maxillary facial processes
R and L mandibular facial processes
_____ and _____ appear and disappear in the 4th week.
Branchial arches and clefts
What is the place where the upper maxillary and lower mandibular processes meet at either side of the stomodeum?
Commissura labiorum oris
Branchial pouch 1 becomes what?
external auditory meatus
In the fourth week the cardiac plate is replaced as the inferior boundary of the stomodeum by what?
the 2 mandibular facial processes
In the fourth week the 2 maxillary facial processes become what boundaries of the stomodeum?
posteriolateral
In the fourth week 2 nasal pits appear within what?
the frontal prominence
After the appearance of nasal pits the frontal prominence becomes 3 processes, what are they?
median nasal facial process
R and L lateral nasal processes
Nasal pits deepen to become what?
nasal ducts that open into the stomodeum, the ducts become nostrils that open into nasal cavities during formation of nasal and oral cavities
During the 4th week, how many facial processes are formed by the first branchial arch and the frontal prominence?
7
What does the median nasal process become?
midline of nose
philtrum of upper lip
What do the lateral nasal processes become?
lateral sides and ala of nose
infraorbital part of face
What do the maxillary processes become?
upper part of cheeks
lateral parts of upper lip
What do the mandibular processes become?
lower part of cheeks
lower lip
chin
In week 4, arch II becomes an embryonic fold of tissue called what?
operculum, it covers arches III and IV and clefts II, III, IV, it becomes the side of the neck below the external auditory meatus
Merging takes place between facial processes during what?
facial formation
If the maxillary facial process or processes do not merge with the median nasal facial process by the 5th week, what occurs?
unilateral or bilateral clefting of the upper lip occurs
Although rare, if the mandibular processes do not merge with each other by the 5th week, what occurs?
clefting of the lower jaw
The buccopharyngeal membrane ruptures allowing what?
An opening into the foregut which becomes the nasal and or pharynx
The buccopharyngeal membrane is the site of what in the adult?
Anterior pillar fauces
