Craniofacial Growth And Development Flashcards
(202 cards)
1
Q
Craniofacial growth and development
What is ontogenesis?
A
Individual development of the human from birth to death
Ontogenesis is a short repetition of phylogenesis.
2
Q
Craniofacial growth and development
Two main periods of ontogenesis according to Boyanov
A
Prenatal development and postnatal development
These periods are classified as a-functional and functional periods.
3
Q
Craniofacial growth and development
Stages of prenatal development
A
*Fertilization
* Embryonic period
* Fetal period
These stages occur before birth.
4
Q
Craniofacial growth and development
Fertilization
A
Fusion of the sex cells nuclei
This process combines genetic material from both parents.
5
Q
Craniofacial growth and development
What happens to the parents’ traits during fertilization?
A
Traits are combined
This results in genetic variation in the offspring.
6
Q
Craniofacial growth and development
Embryogenesis
A
Development of the human, particularly the craniofacial region
This process occurs until the end of the first trimester.
7
Q
Craniofacial growth and development
When tissues and organs formed during human development
A
During the first trimester
This is a critical period for organogenesis.
8
Q
Craniofacial growth and development
Zygote
A
The fertilized egg
It is the initial stage of development after fertilization.
9
Q
Craniofacial growth and development
Morula
A
*Solid ball of cells
* Formed after several mitotic divisions
It occurs after the zygote stage.
10
Q
Craniofacial growth and development
Blastocyst
A
Hollow structure formed from the morula
This stage is crucial for implantation into the uterine wall.
11
Q
Craniofacial growth and development
Type of division occurring in zygote and morula stage
A
Mitotic division
This process is responsible for cell proliferation during early development.
12
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Craniofacial growth and development
Two main types of cells in a blastocyst
A
Embryoblast cells and Trophoblast cells
Embryoblast cells form the embryo, while trophoblast cells contribute to the placenta.
13
Q
Craniofacial growth and development
Function of embryoblast cells
A
They form the embryo
Embryoblast cells are located inside the trophoblast.
14
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Craniofacial growth and development
Trophoblast cells cover
A
The outside of the blastocyst
Trophoblast cells form the embryonic part of the placenta.
15
Q
Craniofacial growth and development
Blastoderm
A
Layer of cells that forms the embryo
It is associated w/ the embryoblast cells.
16
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Craniofacial growth and development
Blastocele
A
Blastocyst cavity full of fluid
It is an important structure within the blastocyst.
17
Q
Craniofacial growth and development
Fill in the blank: The _______ cells cover the outside of the blastocyst.
A
Trophoblast
18
Q
Craniofacial growth and development
True or False: The embryoblast cells are located outside the trophoblast.
A
False
Embryoblast cells are located inside the trophoblast.
19
Q
Craniofacial growth and development
Results from intensive processes of growth and differentiation of embryoblast cells
A
Formation of a bilaminar embryonic disk.
20
Q
Craniofacial growth and development
Bilaminar embryonic disk
A
The body of the embryo.
21
Q
Craniofacial growth and development
Type of cells that form the primitive yolk sac
A
Endodermal cells.
22
Q
Craniofacial growth and development
Type of cells involved in the formation of the ectoderm
A
Ectodermal cells.
23
Q
Craniofacial growth and development
Fill in the blank: The _______ is formed
from the blastocyst cavity.
A
Primitive yolk sac.
24
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Craniofacial growth and development
Cavity associated with the embryo during development
A
Amnionic cavity.
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#Craniofacial growth and development
Structure that assists in the implantation of the embryo
Trophoblast.
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#Craniofacial growth and development
Role of the endometrial epithelium during implantation
It provides the site for embryo implantation.
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#Craniofacial growth and development
True or False: The embryonic disk is a single-layer structure.
False.
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#Craniofacial growth and development
Gastrula
* An embryonic stage following **blastocyst**=>
* Where the **three germ layers** formed.
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#Craniofacial growth and development
Occurs when the bilaminar embryonic disk becomes trilaminar
* The third layer, **mesoderm**, is developed beneath the two layers=>
* Due to migration of **ectodermal cells**.
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#Craniofacial growth and development
Three germ layers formed during gastrulation
* Ectoderm
* Mesoderm
* Endoderm
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#Craniofacial growth and development
Fill in the blank: The _______ is the layer that develops beneath the ectoderm during gastrulation.
[mesoderm]
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#Craniofacial growth and development
True or False: The mesoderm is the first layer formed during the process of gastrulation.
False
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#Craniofacial growth and development
'Amnionic cavity'
The fluid-filled space surrounding the embryo.
34
#Craniofacial growth and development
Fill in the blank: The wall of the _______ is formed by the endoderm.
[primitive yolk sac]
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#Craniofacial growth and development
Structures formed by the ectoderm
*Structures that maintain contact w/outer environment:
* Epithelium of oral mucosa
* Saliva glands epithelium
* Epithelium of olfactory mucosa
* Tooth enamel, dentin, cementum, pulp
* The epidermis and skin appendages (nails, glands)
* Neural tube (central nervous system)
* Skull bones, maxilla, and mandible
## Footnote
Ectodermal derivatives are critical for protective and sensory functions.
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#Craniofacial growth and development
Part of digestive tract the endoderm doesn’t contribute to
The oral part of the digestive tract
## Footnote
Endoderm contributes to the epithelium of the mucosa of the digestive and respiratory tracts, but excludes the oral section.
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#Craniofacial growth and development
Structures formed by the endoderm.
* Epithelium of mucosa of digestive tract
* Epithelium of respiratory tract
* Tongue and pharynx
* Thyroid gland and parathyroid glands
* Liver, pancreas, lungs
## Footnote
Endodermal derivatives are essential for various metabolic and respiratory functions.
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#Craniofacial growth and development
Fill in the blank: The neural tube, which forms the ________, is derived from the ectoderm.
central nervous system
## Footnote
The neural tube is a critical structure that develops into the brain and spinal cord.
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#Craniofacial growth and development
Skin appendages formed from the ectoderm
Skin appendages include:
* Nails
* Glands
## Footnote
These appendages play vital roles in protection, sensation, and thermoregulation.
40
#Craniofacial growth and development
Derivatives of the mesoderm
* Connective tissue
* Muscles of the head and body
* Skeletal bones
* Primitive heart, blood and lymph cells
* The biggest part of innervation
## Footnote
The mesoderm is one of the three germ layers in embryonic development.
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#Craniofacial growth and development
Three primitive axes differentiated during gastrulation
* Neural plate
* Chorda dorsalis
* Primordial gut
## Footnote
These axes are crucial for the development of germ layers.
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#Craniofacial growth and development
Neural plate turns into
Neural tube (formed from ectoderm)
## Footnote
The neural tube is essential for the development of the central nervous system.
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#Craniofacial growth and development
Chorda dorsalis forms
Intervertebral cartilage disks
## Footnote
The chorda dorsalis is important for the structural integrity of the vertebral column.
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#Craniofacial growth and development
Primordial gut forms
Primordial gut tube (formed from endoderm)
## Footnote
The primordial gut tube is the precursor to the gastrointestinal tract.
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#Craniofacial growth and development
Organogenesis
* Formation of different **organs and structures=>**
* Growing and fusion of the three primitive axes
## Footnote
Organogenesis occurs in week 3 of embryonic development.
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#Craniofacial growth and development
Fill in the blank: The _______ is formed from the ectoderm during gastrulation.
Neural tube
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#Craniofacial growth and development
True or False: The primordial gut tube is formed from mesoderm.
False
## Footnote
The primordial gut tube is formed from endoderm.
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#Craniofacial growth and development
Role of ectoderm in head region during embryonic development
* Folds into primordial gut
* Covers primitive oral cavity (Stomodeum)
## Footnote
This process is crucial for the formation of the digestive tract.
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#Craniofacial growth and development
Separates foregut from stomodeum
Buccopharyngeal membrane
## Footnote
This membrane becomes thinner and eventually breaks down.
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#Craniofacial growth and development
Happens to buccopharyngeal membrane during development
*Becomes thinner and later breaks down=>
* Allows continuity between stomodeum and primordial gut
## Footnote
This breakdown is essential for the development of the digestive system.
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#Craniofacial growth and development
Stomodeum
The primitive oral cavity
## Footnote
It is an early structure that plays a role in the development of the mouth.
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#Craniofacial growth and development
Pharyngeal arch apparatus
* Develops in area of **future neck=>**
* Forms significant structures of **head and neck.**
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#Craniofacial growth and development
Number of bilaterally paired arches making up pharyngeal apparatus
5 bilaterally paired arches.
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#Craniofacial growth and development
Type of tissue forming core of each pharyngeal arch
Mesenchyme (embryonic connective tissue).
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#Craniofacial growth and development
Arch I also known as
Mandibular arch
## Footnote
It is the biggest of the pharyngeal arches.
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#Craniofacial growth and development
Structures associated with Arch I?
* 2 maxillary processes
* 2 mandibular processes
* Maxilla
* Mandible
* Masticatory muscles
* n. trigeminus
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#Craniofacial growth and development
Primary nerve associated with Arch II
n. Facialis
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#Craniofacial growth and development
Structures derived from Arch II
* os hyoideum
* Mimetic muscles
* n. Pharyngeus
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#Craniofacial growth and development
Arch contributing to muscles of pharynx and nasopharynx
Arch III
## Footnote
It is associated with the n. glossopharyngeus.
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#Craniofacial growth and development
Muscles associated with Arch IV and VI
Muscles of larynx
## Footnote
They are innervated by n. Vagus.
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#Craniofacial growth and development
What is unique about Arch V?
Does not produce any structures
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#Craniofacial growth and development
Five facial prominences involved in facial development
1. Frontonasal prominence
2. Paired maxillary prominence
3. Paired mandibular prominence
## Footnote
These prominences result from irregular proliferation of mesenchyme in pharyngeal arch I.
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#Craniofacial growth and development
During which weeks does facial development mainly occur?
Weeks 4-8
## Footnote
This period is crucial for the formation and movement of facial structures.
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#Craniofacial growth and development
What type of tissue primarily forms the facial prominences?
Mesenchyme
## Footnote
Mesenchyme is a type of embryonic connective tissue that contributes to the formation of various structures.
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#Craniofacial growth and development
True or False: The maxillary prominence is a paired structure.
True
## Footnote
The maxillary prominence is one of the paired facial prominences that contribute to the development of the upper jaw.
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#Craniofacial growth and development
Fill in the blank: The facial prominences are formed by irregular proliferation of _______.
mesenchyme
## Footnote
This proliferation occurs within pharyngeal arch I.
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#Craniofacial growth and development
Precursors of the nostrils
Nasal pits
## Footnote
The nasal pits eventually develop into the nostrils.
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#Craniofacial growth and development
Components of the frontonasal prominence
* An unpaired frontal prominence
* Two horseshoe-shaped prominences
## Footnote
These horseshoe-shaped prominences surround the nasal pits.
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#Craniofacial growth and development
Unpaired prominence situated in the midline
Frontal prominence
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#Craniofacial growth and development
Two parts of the horseshoe-shaped prominences surrounding nasal pits
* Medial nasal prominence (internal)
* Lateral nasal prominence (external)
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#Craniofacial growth and development
Internal prominence surrounding the nasal pits
Medial nasal prominence
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#Craniofacial growth and development
External prominence surrounding the nasal pits
Lateral nasal prominence
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#Craniofacial growth and development
Groove associated with the maxillary prominence
Nasolacrimal groove
74
#Craniofacial growth and development
Fill in the blank: The nasal pit is part of the _______ prominence.
Frontonasal
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#Craniofacial growth and development
What are optic placodes?
* Precursors of the eyes
* Located between **maxillary and lateral nasal prominence**
## Footnote
Optic placodes are essential in the development of the eyes.
76
#Craniofacial growth and development
Prominences involved in the formation of the optic placodes
Maxillary and lateral nasal prominences
## Footnote
These facial prominences play a crucial role in the embryonic development of facial features.
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#Craniofacial growth and development
Nasolacrimal groove
A groove formed between maxillary and lateral nasal prominences
## Footnote
This groove is significant in the development of the nasolacrimal duct.
78
#Craniofacial growth and development
When the fusion of facial processes occurs
Week 7-10
## Footnote
This period is critical for the proper formation of facial structures.
79
#Craniofacial growth and development
Medial nasal prominences form
* Midline of the nose
* Philtrum of the upper lip
## Footnote
The fusion of these prominences is essential for the central features of the face.
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#Craniofacial growth and development
Lateral nasal prominences form
Ala of the nose
## Footnote
The ala refers to the outer part of the nostrils.
81
#Craniofacial growth and development
Maxillary prominences form
Lateral portion of the upper lip
## Footnote
The maxillary prominences are key to the formation of the upper jaw and lip.
82
#Craniofacial growth and development
Fill in the blank: The fusion of the facial processes is crucial for the development of the _______.
Face
## Footnote
Proper fusion prevents facial clefts and other anomalies.
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#Craniofacial growth and development
What is the maxilla formed from?
* The fusion of two medial nasal prominences w/ the maxillary and lateral nasal prominences
## Footnote
The maxilla is a key facial bone that plays a crucial role in the structure of the face.
84
#Craniofacial growth and development
During which weeks does the palate form?
Week 6-12
## Footnote
This period is critical for the development of the oral cavity and associated structures.
85
#Craniofacial growth and development
Primary palate also known as
Premaxilla
## Footnote
The primary palate is formed from the fusion of the two medial nasal prominences.
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#Craniofacial growth and development
How secondary palate formed
* Fusion of paired **lateral palatine shelves=>**
* Which arise from the **maxillary prominences**
## Footnote
This process begins at the end of the first month of development.
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#Craniofacial growth and development
Components involved in the formation of the maxilla
* Medial nasal prominences
* Maxillary prominences
* Lateral nasal prominences
## Footnote
These components are essential for the proper formation of the facial structure.
88
#Craniofacial growth and development
Fill in the blank: The primary palate is formed from the fusion of the two _______.
Medial nasal prominences
## Footnote
This fusion is a critical step in the development of the oral cavity.
89
#Craniofacial growth and development
Lateral palatine shelves derived from
Maxillary prominences
## Footnote
These shelves are crucial for the formation of the secondary palate.
90
#Craniofacial growth and development
True or False: The secondary palate begins to form at the end of the first month.
True
## Footnote
The development of the secondary palate is a vital part of craniofacial development.
91
#Craniofacial growth and development
What occurs until the 50-56 day mark in palatine development?
* Complete fusion=>
* Lateral palatine shelves w/ each other
* Nasal septum
* Primary palate
## Footnote
This process separates the nasal cavity from the oral cavity.
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#Craniofacial growth and development
Consequence of interference with the fusion of palatine structures
Cleft
## Footnote
This can lead to conditions such as cleft lip or cleft palate.
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#Craniofacial growth and development
Term for the midline fusion of the palatine shelves
Median palatine raphe
## Footnote
This structure is a key feature in the anatomy of the palate.
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#Craniofacial growth and development
Period during which the mandible, lower lip, and chin are formed
Between days 30-35=>
* From fusion of the two mandibular prominences
## Footnote
This process is crucial for the development of the lower facial structure.
95
#Craniofacial growth and development
When the enamel organs of the 20 primary teeth form
* During 2nd month of pregnancy =>
* In the gum pads
##Footnote
This marks the initial stage of dental development.
96
#Craniofacial growth and development
Structures' enamel buds form later during dental development
Permanent first molar, incisors, and canines
## Footnote
These are essential for the development of permanent teeth.
97
#Craniofacial growth and development
Term for the developing organism after the first trimester until birth
Fetus
## Footnote
This term indicates a significant stage in prenatal development.
98
#Craniofacial growth and development
What happens to the length, height, thickness, and width of facial bones during the postnatal period?
They continue to increase.
## Footnote
This indicates ongoing growth and development of the facial structure after birth.
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#Craniofacial growth and development
In a newborn, how does the size of the cranium compare to the face?
The cranium is larger relative to the face.
## Footnote
This indicates that the head is proportionally dominated by the cranium in newborns.
100
#Craniofacial growth and development
Percentage of total head the cranium represents in a newborn
More than half of the total head.
## Footnote
This highlights the significant proportion of the head that is made up by the cranium at birth.
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#Craniofacial growth and development
Growth
* An increase in **size, number, and mass of the tissues**
* Or their **decrease** (reverse growth-regress)
## Footnote
Growth is related but not synonymous with development.
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#Craniofacial growth and development
Development
* An increasing degree of **organization and differentiation=>**
* Of **tissues, structures, organs, or functions**
## Footnote
Examples include the development of anatomic structures like the brain and functions such as speech and behavior.
103
#Craniofacial growth and development
How growth related to development
Growth is related but not synonymous with development
## Footnote
Both concepts involve changes in size and function, but they represent different processes.
104
#Craniofacial growth and development
What initiates growth?
Somatotropic hormone of the thyroid gland
## Footnote
This hormone plays a crucial role in stimulating growth processes.
105
#Craniofacial growth and development
True or False: Growth and development are synonymous.
False
## Footnote
While they are related, growth and development refer to different processes.
106
#Craniofacial growth and development
Fill in the blank: An increase in the size, number, and mass of tissues is known as _______.
[growth]
107
#Craniofacial growth and development
Fill in the blank: The increasing degree of organization and differentiation of tissues is known as _______.
[development]
108
#Craniofacial growth and development
Hypertrophy
Increase in the size of individual cells
## Footnote
This process contributes to the overall growth of tissues.
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#Craniofacial growth and development
Hyperplasia
Increase in the number of cells
## Footnote
This can lead to an enlargement of tissues or organs.
110
#Craniofacial growth and development
What does secretion of extracellular material result in?
Increase in the size of organs regardless of the number or size of the cells themselves
## Footnote
This can occur in both soft and hard tissues.
111
#Craniofacial growth and development
What type of growth involves both hyperplasia and hypertrophy?
Interstitial growth
## Footnote
This type of growth can occur in soft and hard tissues.
112
#Craniofacial growth and development
Role of extracellular material in skeletal growth
Contributes to formation of hard tissues like bone.
## Footnote
Secretion of extracellular material which mineralizes later
113
#Craniofacial growth and development
Surface apposition of bone
Growth that occurs by adding new layers on the surface
## Footnote
This is a process distinct from interstitial growth.
114
#Craniofacial growth and development
Type of tissue involved in the growth of the facial skeleton
Hard tissue
## Footnote
Hard tissue includes bone and cartilage that make up the facial skeleton.
115
#Craniofacial growth and development
Type of growth occurring in the first years after birth
Interstitial growth
## Footnote
Interstitial growth refers to the growth that occurs from within the tissue, common in early development.
116
#Craniofacial growth and development
Growth pattern of bone after the age of 20-25 years
Surface apposition of bone
## Footnote
Surface apposition refers to the process of new bone being added to the surface of existing bone.
117
#Craniofacial growth and development
Age growth finishes for the facial skeleton
> 25-30 years
## Footnote
Growth typically concludes in the late 20s to early 30s.
118
#Craniofacial growth and development
Where interstitial growth observed
In connective tissues and cartilages
## Footnote
Examples include sutures, synchondrosis, and condylar cartilage.
119
#Craniofacial growth and development
Where surface apposition of bone observed
In the periosteum of existing bones
## Footnote
The periosteum is a dense layer of vascular connective tissue enveloping the bones.
120
#Craniofacial growth and development
How much bones thicken per year during growth
3.5 mm/year
## Footnote
This thickness is part of the process of surface apposition of bone.
121
#Craniofacial growth and development
Proportion of total body size a newborn's head represents
¼ of the total body size.
## Footnote
In adults, the head represents 1/8 of the total body size.
122
#Craniofacial growth and development
Proportion of total head size a newborn's face represents
1/8 of the total head size.
## Footnote
In adults, the face represents 1/3 to ½ of the total head size.
123
#Craniofacial growth and development
What is the cranio-caudal gradient of increase in normal growth?
* The body grows more than the head
* The facial skeleton more than the cranium
* The mandible more than the maxilla.
## Footnote
This reflects the differential growth rates of various parts of the body.
124
#Craniofacial growth and development
Do different tissues grow at the same speed during postnatal development?
No, different tissues grow with different speed.
## Footnote
For example, muscles and skeleton develop faster than the body of the mandible and the alveolar processes.
125
#Craniofacial growth and development
Up to what age do the mandible and alveolar processes grow at various different speeds?
Up to 13 years of age.
## Footnote
This indicates that growth rates can vary significantly during early development.
126
#Craniofacial growth and development
characteristics of growth in the craniofacial complex
The characteristics include:
* SITES or location of growth
* TYPE of growth occurring at that location
* MECHANISM of growth
* DETERMINANTS or controlling factors of that growth
## Footnote
These characteristics help in understanding how craniofacial structures develop and change.
127
#Craniofacial growth and development
Two types of growth that can occur in the craniofacial complex
* Intramembranous bone formation
* Endochondral ossification
## Footnote
Intramembranous bone formation involves the direct conversion of mesenchymal tissue into bone, while endochondral ossification involves the replacement of cartilage with bone.
128
#Craniofacial growth and development
What does the MECHANISM of growth refer to?
How growth changes over time
## Footnote
This includes the biological processes and factors that influence the growth patterns in the craniofacial complex.
129
#Craniofacial growth and development
DETERMINANTS of growth in the craniofacial complex include
* Genetic factors
* Environmental influences
* Functional demands
## Footnote
These determinants play a crucial role in shaping the development and morphology of craniofacial structures.
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#Craniofacial growth and development
Fill in the blank: The _______ of growth in the craniofacial complex includes the sites or location where growth occurs.
[SITES]
## Footnote
Understanding the specific sites of growth is essential for studying craniofacial development.
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#Craniofacial growth and development
Growth site
Location at which bone enlarges and moves
## Footnote
Growth can be stimulated or repressed by external factors.
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#Craniofacial growth and development
Growth centre
Locations at which independent growth occurs (genetically controlled)
## Footnote
Growth centres are also growth sites but sites are not always growth centres.
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#Craniofacial growth and development
Examples of growth sites.
* Sutures
* Periostal tissue
## Footnote
These are locations where bone growth occurs.
134
#Craniofacial growth and development
Example of a growth centre
* Cartilages
## Footnote
These are areas where genetically controlled growth takes place.
135
#Craniofacial growth and development
True or False: All growth sites are growth centres.
False
## Footnote
Growth centres are specific types of growth sites, but not all sites function as centres.
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#Craniofacial growth and development
What is ENDOCHONDRAL BONE FORMATION?
* Bone forms from **cartilaginous precursor**=>
* Where blood vessels grow in cartilage, leading to ossification.
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#Craniofacial growth and development
Steps involved in ENDOCHONDRAL BONE FORMATION?
1. Islands of bone appear in surrounding cartilage.
2. Cartilage is totally replaced by bone.
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#Craniofacial growth and development
What is INTRAMEMBRANOUS BONE FORMATION?
* Bone formed by secretion of bone matrix called 'osteoid'=>
* From osteoblasts directly into connective tissues.
139
#Craniofacial growth and development
Main difference between endochondral and intramembranous bone formation
Endochondral involves a cartilage precursor, while intramembranous does not involve cartilage.
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#Craniofacial growth and development
Fill in the blank: In ENDOCHONDRAL BONE FORMATION, blood vessels grow in _______.
cartilage
141
#Craniofacial growth and development
True or False: INTRAMEMBRANOUS BONE FORMATION involves an intermediate formation of cartilage.
False
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#Craniofacial growth and development
What is the first mechanism of skeletal growth?
Remodeling
## Footnote
Involves periosteal and endosteal cells removing and adding bone.
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#Craniofacial growth and development
What happens during the remodeling process?
Resorption of bone in one area and apposition of bone in another
## Footnote
This leads to changes in size and shape of the bone.
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#Craniofacial growth and development
Define primary translation in skeletal growth.
Displacement of the bone itself in space
## Footnote
Occurs as a result of bone remodeling.
145
#Craniofacial growth and development
What is secondary translation in skeletal growth?
* Displacement of the entire bone=>
* Due to expansion of adjacent attached structures
## Footnote
This is different from primary translation.
146
#Craniofacial growth and development
Fill in the blank: The process of removing bone in one area and adding it in another is called ______.
Remodeling
147
#Craniofacial growth and development
True or False: Primary translation involves the entire bone moving due to the expansion of adjacent structures.
False
## Footnote
Primary translation refers to the bone itself changing position.
148
#Craniofacial growth and development
Main components of the craniofacial region
Skull, Facial skeleton, Nasomaxillary complex, Mandible
## Footnote
The cranioracial region includes both the skull and the facial structures.
149
#Craniofacial growth and development
What is the cranial vault?
The upper part of the skull that encloses the brain
## Footnote
It provides protection for the brain and supports the head.
150
#Craniofacial growth and development
What is the cranial base?
The bottom part of the skull that supports the cranial vault
## Footnote
It serves as the foundation for the skull and connects to the spinal column.
151
#Craniofacial growth and development
The skull consists of
* The cranial base and cranial vault
152
#Craniofacial growth and development
The facial skeleton consists of
*Nasomaxillary complex
*Mandible
153
#Craniofacial growth and development
Cranial vault formation
* Formed by **five flat bones**=>
* Created prenatally through **intramembranous ossification** of mesenchymal tissue surrounding the developing brain.
## Footnote
The cranial vault protects the brain and supports the structures of the head.
154
#Craniofacial growth and development
Mechanisms of growth for the cranial vault
1. Direct apposition of bone in sutures and fontanelles.
2. Surface remodeling w/periosteal apposition of bone externally and bone resorption internally.
## Footnote
These mechanisms help in increasing the thickness and changing the form of the cranial bones.
155
#Craniofacial growth and development
What happens to cranial sutures by the 2nd year and the 15th year?
* Up to the 2nd year, sutures composed of connective tissue (syndesmosis).
* After 15th year, their ossification ends, converting them into synostosis.
## Footnote
* This transition affects flexibility and growth of cranial vault.
* Synchondroses different from symphyses (secondary cartilaginous joints), which are formed of fibrocartilage, and from synostosis (ossified junctions), which is the fusion of two or more bones.
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#Craniofacial growth and development
Role of fontanelles in cranial vault development
* Sites of growth
* Facilitate passage of baby through birth canal=>
* Increasing flexibility of cranial vault.
## Footnote
The flexibility provided by fontanelles is crucial during childbirth.
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#Craniofacial growth and development
Fill in the blank: The five flat bones of the cranial vault are formed prenatally by means of __________.
intramembranous ossification.
## Footnote
This process is essential for the development of the cranial vault.
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#Craniofacial growth and development
Follows the growth of the cranial vault
Brain growth
## Footnote
The cranial vault expands in relation to the growth of the brain.
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#Craniofacial growth and development
Percentage of adult cranial vault size reached by the 5th year
90%
## Footnote
This indicates significant early growth in the cranial vault.
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#Craniofacial growth and development
At what age does the cranial vault reach 100% of adult size?
15 years
## Footnote
Full adult size is achieved by the end of adolescence.
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#Craniofacial growth and development
List the bones of the cranial vault.
* Frontal
* Parietal
* Sphenoidal
* Occipital
* Temporal
## Footnote
These bones collectively form the protective structure of the skull.
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#Craniofacial growth and development
Observed when there are pathological processes in the Brain
Compensatory growth
##footnote
e.g hydrocephalia
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#Craniofacial growth and development
Type of growth in the cranial base
Endochondral ossification of several cartilages (frontal, ethmoid, sphenoid, occipital)
## Footnote
These cartilages are formed, enlarged, and fused in utero.
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#Craniofacial growth and development
First mechanism of growth for the cranial base
**Endochondral ossification** of the **synchondroses** which connect bone segments
## Footnote
* This mechanism results in an increase in the length of the cranial base.
* Synchondroses=>type of cartilaginous joint where hyaline cartilage completely joins together two bones
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#Craniofacial growth and development
Second mechanism of growth for the cranial base
* Surface remodeling w/ periosteal apposition of bone on the external surface
* Resorption on the internal surface
## Footnote
This increases the size of the bones of the cranial base to adapt to the enlargement of the ethmoidal and sphenoidal air sinuses. Ugh
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#Craniofacial growth and development
What role do the synchondroses play in cranial base growth?
Sites and centres of independent genetically controlled growth
## Footnote
This determines the cranial base as the most stable and less susceptible to external factors in the craniofacial complex.
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#Craniofacial growth and development
True or False: The cranial base is highly susceptible to external factors.
False
## Footnote
The cranial base is determined to be the most stable structure in the craniofacial complex.
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#Craniofacial growth and development
Fill in the blank: The cranial base undergoes _______ ossification.
endochondral
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#Craniofacial growth and development
Cartilages involved in the growth of the cranial base
* Frontal
* Ethmoid
* Sphenoid
* Occipital
## Footnote
These cartilages are crucial for the formation and growth of the cranial base.
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#Craniofacial growth and development
Growth characteristics of the cranial base
Is complex, uneven, and in different directions.
## Footnote
This complexity affects various cranial structures and their relationships.
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#Craniofacial growth and development
Why anterior cranial fossa important in orthodontics
* Stable reference radiographic structure for measuring cephalometric changes in facial growth.
## Footnote
This stability is crucial for effective orthodontic treatment.
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#Craniofacial growth and development
Typical age of ossification for spheno-occipital synchondrosis in girls
Up to the 13-15th year.
## Footnote
This age range indicates the developmental differences between genders.
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#Craniofacial growth and development
Typical age of ossification for spheno-occipital synchondrosis in boys
Up to the 15-17th year.
## Footnote
This developmental milestone can influence craniofacial relationships.
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#Craniofacial growth and development
How growth of the spheno-occipital synchondrosis affects cranial base length
* **Increases** length of cranial base
* Changes angle between **anterior and middle cranial fossa**
## Footnote
These changes have implications for facial structure development.
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#Craniofacial growth and development
Relationships influenced by the growth of the cranial base
The relationship between the maxilla and mandible.
## Footnote
This relationship is critical for proper occlusion and facial aesthetics.
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#Craniofacial growth and development
Dysplasia in the spheno-occipital synchondrosis leads to
The development of class III malocclusion.
## Footnote
Class III is characterized by a protruded mandible relative to the maxilla.
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#Craniofacial growth and development
What happens with increased growth of the cranial base?
* It elongates cranial base
* Moves mandible back to the maxilla=>
* Forming class I malocclusion.
## Footnote
Class I is typically characterized by a normal occlusal relationship.
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#Craniofacial growth and development
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#Craniofacial growth and development
What does the nasomaxillary complex consist of?
Maxilla, Nasal bones, Bones to which the maxilla is attached
## Footnote
The nasomaxillary complex is a significant anatomical structure in the facial skeleton.
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#Craniofacial growth and development
Type of growth associated with the nasomaxillary complex
* Intramembranous ossification of mesenchymal tissue
## Footnote
This type of growth occurs with the exception of the ethmoidal bone and the nasal septum.
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#Craniofacial growth and development
Mechanism of growth for the nasomaxillary complex
Direct apposition of bone in the sutures
## Footnote
The sutures connect the nasomaxillary complex with the skull.
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#Craniofacial growth and development
Direction of growth of the maxilla
Backward and upward
## Footnote
This growth continues until it reaches the cranial base.
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#Craniofacial growth and development
Role of sutures in the growth of the nasomaxillary complex
* Sites of growth=>
* Define a particular pattern of growth
## Footnote
Sutures can be influenced by external factors, including orthodontic forces.
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#Craniofacial growth and development
True or False: The growth of the nasomaxillary complex can be accelerated or inhibited.
True
## Footnote
This can be achieved by influencing the growth of the sutures.
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#Craniofacial growth and development
Second mechanism of growth in the nasomaxillary complex
* Surface remodeling of all maxillary bone structures=>
* By the periosteum and endosteum cells.
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#Craniofacial growth and development
Type of growth in the tuberosity region and supraorbital ridges
Apposition.
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#Craniofacial growth and development
Where resorption occurs in the nasomaxillary complex?
In the outer anterior surface.
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#Craniofacial growth and development
Fill in the blank: The nasomaxillary complex undergoes _______ in the tuberosity region.
apposition.
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#Craniofacial growth and development
True or False: Resorption in the nasomaxillary complex occurs in the inner structures.
False.
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#Craniofacial growth and development
Third mechanism of growth in the nasomaxillary complex
* Primary displacement=>
* Nasomaxillary complex translated **downward and forward**
=> Due to three-dimensional growth of the maxillary sutures.
## Footnote
This mechanism is essential for understanding how the nasomaxillary complex develops in relation to the cranial base.
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#Craniofacial growth and development
What causes secondary displacement of the nasomaxillary complex?
* Push from behind created by cranial base growth
## Footnote
* * Particularly from growth of spheno-ethmoidal synchondrosis up to the 7th year.
* This displacement plays a significant role in the overall development of the nasomaxillary complex.
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#Craniofacial growth and development
Role nasal septum plays in displacement of the maxilla
* Grows downward and forward=>
* Initiating anterior displacement of maxilla to which it is connected.
## Footnote
This growth is critical for proper alignment and positioning of the maxilla in relation to other facial structures.
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#Craniofacial growth and development
What type of ossification occurs in the growth of the mandible?
Intramembranous ossification and endochondral ossification
## Footnote
Intramembranous ossification occurs within the mesenchymal tissue of the mandibular process, while endochondral ossification involves the condylar cartilage and symphysis.
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#Craniofacial growth and development
Where intramembranous ossification of the mandible occurs
Within the mandibular process of the 1st pharyngeal arch
## Footnote
This process occurs laterally to Meckel's cartilage.
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#Craniofacial growth and development
What happens to Meckel's cartilage during mandible development?
It disintegrates and largely disappears
## Footnote
This occurs as the bony mandible develops.
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#Craniofacial growth and development
Condylar cartilage ossification in the mandible
It undergoes endochondral ossification
## Footnote
This process is essential for the formation of the condyle of the mandible.
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#Craniofacial growth and development
Fill in the blank: The mandible develops laterally to _______.
Meckel's cartilage
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#Craniofacial growth and development
What type of ossification does the condylar cartilage undergo?
Endochondral ossification
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#Craniofacial growth and development
In which direction does the condylar cartilage grow?
Upward and backward
200
#Craniofacial growth and development
Role of surface remodeling in the mandible
* Maintain specific anatomic form=>
* Through periosteal and endosteal apposition or resorption
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#Craniofacial growth and development
Primary displacement of the mandible during growth
Translated downward and forward
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#Craniofacial growth and development
Secondary displacement of the mandible due to glenoid fossa growth
Translated downward and backward
