Human Systems And Embryology Flashcards
What are the features of an infant skull?
Eyes are large, ears are low set
Forehead upright and bulbous: face appears broad
Nasal region is vertically shallow with nasal floor close to inferior orbital rim
What are the 3 ways an infant skull can grow?
At sutures or periosteal lined contact areas
In cartilage
By surface deposition
Where in the skull does growth appear at sutures/periosteal lined contact areas?
Between the flat bones of the cranial vault and between the bones of the cranium and maxillary
Where in the skull does growth occur at cartilage?
Synchondroses between the bones forming the base of the skull
In the mandibular condyle and in the cartilage of the nasal septum
Where in the skull does growth occur by surface deposition?
Over the surfaces of the cranial and facial bones
Beneath the covering periosteum
How does the cranial vault grow?
The cranium expands in response to the growing brain (until 6-7 years)
After neural growth ceases, the forehead continues to expand due to enlarging air sinuses
How does the cranial base grow?
Synchondroses
At what age is the lateral growth of the cranial base completed by?
3 years
At what age does the sphenoethmoidal Synchondroses fuse?
6-7 years
At what age does growth cease at the sphenoid-occipital Synchondroses and what age does it fuse?
12-15 years
20 years
What direction does the maxilla grow?
Downward and forward
Where does maxillary growth occur?
At sutures between maxilla and skull
Where does surface deposition occur in maxillary growth?
Posteriorly
Where does surface resorption occur in maxillary growth?
Anteriorly and inferiorly
What direction does the mandible grow in?
Downwards and forwards
Where does mandibular growth occur?
Condylar cartilage
Where does surface resorption occur in mandibular growth?
Anteriorly and lingually
Where does surface deposition occur in mandibular growth?
Posteriorly and laterally
When do the mandible and maxilla grow in width in males and females?
Before pubertal growth spurt: 9-10 years
When do the mandible and maxilla grow in length in males and females?
Throughout puberty:
Males- 18 years
Females- 14-15 years
When does vertical growth of the mandible and maxilla end in males and females?
Males: 20s
Females: 17-18
What are the 4 predictors of pubertal growth spurt?
Chronological age
Secondary sexual characteristics
Hand-wrist radiographs
Cervical vertebral maturation (CVM)
What is CVM 1-6?
CS1/2; growth approaching
CS3; peak growth in 1 years
CS4; peak growth past
CS5/6; peak growth ended
What do forward growth rotations lead to?
A short face
What do downwards and backwards growth rotations lead to?
A long face
In a lat cephalogram what do the following mean?
S
N
A
B
ANS
PNS
Pog
M
Go
Po
Or
Ba
S; Sella
N; Nasion
A; A point
B; B point
ANS; Anterior Nasal Spine
PNS; Posterior Nasal Spine
Pog; Pogonion
M; Mentón
Go; Gonion
Po; Ponion
Or; Orbital
Ba; Basion
In a lat cephalogram what do the following mean?
S
N
A
B
ANS
PNS
Pog
M
Go
Po
Or
Ba
S; Sella
N; Nasion
A; A point
B; B point
ANS; Anterior Nasal Spine
PNS; Posterior Nasal Spine
Pog; Pogonion
M; Mentón
Go; Gonion
Po; Ponion
Or; Orbital
Ba; Basion
When is full masticatory function developed?
2 years
What is the language development stage at 1 year?
Understands 20 words/simple phrases
Uses 2-3 words
What is the language development stage at 2 years?
Understands simple commands/ questions
Uses 100 words
What is the language development stage at 3 years?
Understands prepositions, object function, simple conversation
Uses 4 word sentences
What is the language development stage at 4 years?
Understands colours, numbers, tenses
Uses long grammatical sentences
What is the periodontium?
Tissues that surround and support the teeth
What is the role of the periodontium?
Retain teeth in sockets
Resist masticatory loads
Defensive barrier
What does cementum do?
Covers root dentine
Provides attachment for some periodontal fibres