Craniofacial Bone Complex and Joints Flashcards

1
Q

Human Skeleton

About 270 bones at birth Reduced to 206 by Adulthood

Axial Bones
Skull: _____ bones plus _____ associated bones
Torso: 52 bones

Appendicular bones
Upper extremities: 64 bones Lower extremities:62 bones

A

22

9

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2
Q

The Skull
_____: The region of the skull that encases the brain

_____:
The region of the skull that makes up the bones of the face

A

neurocranium

vicerocranium

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3
Q

Neurocranium

Cranial _____:
The portion of the skull that overlies the brain; It is formed by _____ ossification

Cranial _____:
The portion which underlies the brain; It is formed through _____ ossification (_____)

A
vault
intramembranous
base
endochondral
chondrocranium
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4
Q

Membranous bones of the skull:

Membranous bones making up the calvarium of the skull are each derived from the _____ ossification center.

how membranous bones develop

week _____: bony spicules, ossification centers grow outward and then they meet; the area where they meet never really _____ > develops into the cranial _____

occipital, parietal, frontal, maxilla, mandible, nasal bone

A

primary
6-7
ossifies
sutures

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5
Q

Development of Cranial base: Chondrocranium

Cartilaginous precursors of the cranial base, several small cartilages form a central stem and other cartilages outline paired lateral structures, begin to appear at about _____ weeks of development in the mesoderm or ectomesenchyme separating the brain above from the rest.

The chondrocranium is fully fused and differentiated by the end of the _____ month of pregnancy, or _____ weeks since the initiation of cartilage formation.

Mineralization of the chondrocranium takes place at various centres of
ossification that appear in the cartilages of the cranial base

A

7
second
2

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6
Q

Alveolar process of maxilla

alveolar process - teeth are embedded; different from the rest of bone, develops in a different _____; present only when teeth are present, when no teeth > it _____ and _____

A

manner
regresses
disappears

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7
Q

Prenatal Growth and Development of Maxilla:

  • Maxilla forms within the maxillary _____ extending ventrally from the _____ arch
  • _____ ossification
  • Ossification starts in _____ week
  • _____ development

mandibular arch is the _____ brachial arch > has a maxillary process that extends and forms the upper face; ossification begins here

brachial arch is _____ (maxilla is derived from neural crest)

A
prominences
mandibular
intramembranous
7th
palatal

first
neural crest

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8
Q

Postnatal Growth and Development :

Two Basic Modes of Growth Movements

  1. Remodeling:
    Deposition and resorption of bone
    (a) _____
    (b) _____
  2. Displacement:
    Growth movements which cause separation of the different bones
    (a) _____
    (b) Cranial base _____
A

cortical drift
relocation

sutural growth
synchondrosis

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9
Q

Postnatal Growth and Development

intramembranous > bone is added on the surface, only grows by _____ growth

as you go from immature to mature bone; you must ____ (cortical drift/relocation)

A

appositional

remodel

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10
Q

Remodeling and Relocation vs. Cortical Drift

EXPLAIN ME

A

YES

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11
Q

Remodeling of Palate

ü Bone ____ on oral side
ü Bone ____ on nasal side

A

deposition

resorption

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12
Q

know that the maxilla (maxillary tuberosity, alveolar processes) grows via a ____ process

A

remodeling

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13
Q

Mandible

mandibular notch, when condyle is absorbed in arthritis, you will see changes in the mandibular ____

A

notch

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14
Q

Mandible: Prenatal Growth & Development

  • ____ week in uterine
  • ____ & ____ ossification
A

6th
intramembranous
endochondral

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15
Q

Body:
The mandible is ossified in the fibrous membrane covering the outer surfaces of ____ (6th wk)

meckel’s cartilage forms the original ____, but never turns into the mandible; serves strictly as the ____ structure; formed by ____ ossification

A

meckel’s cartilages
temple
positioning
intramembranous

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16
Q

Ramus:

The condylar cartilage - Carrot shaped cartilage appears (____ wk) in the region of the condyle and occupies most of the developing ramus. Converts to bone by ____ ossification (____ wk), forming condyle head and neck.

Coronoid process - A small strip of cartilage appears along the anterior border of the coronoid process. It is invaded by the surrounding membrane bone and undergo absorption (____ wk).

condylar cartilage is maintained until ____; cartilage in coronoid process ____

A

10th
endochondral
14th

10-14th

puberty
regresses

17
Q

Alveolar Bone

It starts when the deciduous tooth germs reach the early ____ stage. The bone of the mandible begins to grow on each side of the tooth germ.

The alveolar processes grow at a rapid rate during the periods of ____.

A

bell

tooth eruption

18
Q

Mandible: Postnatal Growth & Development
Main Growth Sites:
ü Secondary Cartilage (____ Cartilage)
ü ____ Ridge
ü The Ramus
ü Lingual ____

A

condylar
alveolar
tuberosity

19
Q
  1. Condylar Cartilage:
    • ____ cartilage
    • Functions as ____ cartilage and ____ site (which is why it is formed by both intra/endo ossification).
    • Adoptive response to mechanical ____ and development
    • Growth of condylar cartilage helps in:
    - Increase in ____ of the mandibular ramus
    - Increase in the overall ____ of the mandible
    - Increase of the inter condylar distance (____)
  2. Growth with the alveolar process:
    • Due to the increase in the space between the upper and lower jaws a space created between the opposing teeth to erupt. This means that bone deposition contributes to the growth of the body of the mandible in ____.
A
secondary
articular
growth
stress
height
length
width

height

20
Q
  1. Ramus:

Periosteal bone apposition and resorption (bone remodeling) help in mandible growth. The results depend on the place of bone remodeling. Growth can occur in ____, ____ and ____

Move posteriorly by bone deposition on ____ border and resorption on ____ border. The anterior part of the ramus becomes the ____

A

height
length
width

posterior
anterior
corpus

21
Q

Width
Completed before ____ growth spurt at around age ____

Length
Continues through puberty
- Girls: ____ years
- Boys: ____ years

Height
Continues into ____ after the growth spurt

large mandible > jaw surgery > you want it to be passed the time of length completion (girls for 16, boys closer for 20)

height growth until adulthood becomes a problem for placing dental implant in teenagers (18 y.o.); the dental implant will still behind, nowadays implants are placed much later on (girls 20, boys even later)

A

adolescent
12

14-15
18-19

adult

22
Q

Jaw Alignment

Class I = ____
Class II = ____
Class III = ____

class III > if overgrown mandible, postpone surgery because mandible continues to grow until later in life (bc has it’s own growth potential)

A

balanced jaw relationship
underdeveloped mandible
overgrown mandible/underdeveloped maxilla

23
Q
JOINTS in the SKULL
•  \_\_\_\_ 
•  Sutures
•  \_\_\_\_ 
•  Gomphosis

TMJ is not identical to other synovial joints in the body; synovial joints in the skull are ____

not unique joint structure in skull > synchondroses/sutures (____ and ____ are unique in skull)

A

synchondroses
synovial joint

unique

synovial joints
gomphosis

24
Q

Synchondrosis

  • A union between two bones by the formation of either ____ cartilage or ____ cartilage
  • Usually ____ and exists during the growing phase until the intervening cartilage becomes progressively ____ and ultimately becomes obliterated and converted into bone before adult life
A

hyaline
fibro
temporary
thinner

25
Q

Midline Synchondroses of Cranial Base

Important ____ for the skull

Spheno-ethmoid Synchondrosis closes at ____

Intersphenoid Synchondrosis ossifies at ____

Spheno-occipital synchondro closes between age ____

intersphenoid synchondrosis very little ____ contribution

orthodontists love the ____ synchondrosis; cannot manipulate cartilage

A

growth center

age 6
birth
13-15

post-natal
spheno-occipital

26
Q

Epiphyseal growth plate of long bones:
Resting/Proliferating/Hypertrophic

Synchondrosis
Hypertrophic/Prolif/Resting
/Prolif/Hypertrophic

REWATCH ME

A

HALLO

27
Q

Cranial Base Synchondroses are Important “Growth Center”

Ex vivo explant experiment showed that spehnoid-occipital synchondrosis can enlarge independently without ____ factors.

Cranial base synchondroses are regarded as important growth centers of the craniofacial skeleton, particularly the ____ synchondrosis because of its late ossification and important contribution to post-natal cranial base growth

has intrinsic potential to how much it grows; ____ programmed

Timing of Closure:
• Spheno-ethmoid S: ____ yrs
• Interspenoidal S: at ____
• Spheno-occipital S: ____ yrs

A
extrinsic
spheno-occipital
6
birth
13-15
28
Q

Abnormal Development of the Cranial Base:

  • ____ (Apert, Crouzon, Pfeiffer)
  • Down’s syndrome
  • ____ syndrome
  • Klinefelter syndrome
  • ____ syndrome
  • Achondroplasia

Premature growth arrest of the cranial base leads to midface ____ and reduced midfacial ____

A
syndromic craniosynostosis
turner
william's
retrusion
height
29
Q

Premature Closure of the Cranial Base - ____ distraction osteogenesis

A

Lefort II

30
Q

Temporomandibular Joint (TMJ)

  • The only movable ____ in the head that connects the mandible to the rest of the skull
  • One of the most used joints in the body
  • Biting force, ____ lbs/in2
A

synovial joint

600-1000

31
Q

TMJ movement

only when open a half inch = ____ movement

when you open more; the disc and the joint slides forward; ____ movement > exerts a lot of stress to the joint; which is protected by the ____

A

roll
translational
articular disc

32
Q

TMJ movement

when closed; disc sits right on top; when you open the disc moves with the condyle; protects the condyle, the tip of condyle is thin articular cartilage so it requires protection

when abnormal; disc is ____ displaced; ____ stage, the condyle moves so the disc gets placed back on top of the condyle

or it can be totally ____ so the disc does not return to the top of the condyle; when this continues > ____

treatment > remove the disc, or pull the disc back over top of the condyle

Osteoarthritis
• Surface ____
• Perforation of ____
• Fibrous ____

A

anteriorally
early
locked
osteoarthritis

erosion
disc
adhesion

33
Q
Joint Lubricants in TMJ:

•  \_\_\_\_
•  \_\_\_\_
•  Surface Active Phospholipids

Lack of lubrication > increased ____ > adhesion, displacement, ____, distortion of the articular disc > degenerative arthritic change

A

lubricin
hyaluronate (HA)

friction
hypertropy

34
Q

The effect of loss of Lubricin function in PRG4 knock out mouse TMJ

Lubricin has ____ and ____ activities

PRG4 makes ____; when KO the gene, the disc becomes ____, and the increase of protein deposit on the ____ chamber, and the disc changes its properties

after 3 months, ____ of the surface and ____ of the disc

A

anti-adhesion
anti-cell growth

lubricin
thick
upper

erosion
adhesion

35
Q

HA-deficient TMJ in
Has2f/f;Aggrecan CreERT2

Has2f is the enzyme that makes ____, when KO the join starts to change in appearance, the cartilage looks VERY ____

really ____ cells on top of the cartilage, cracking of the cartilage surface, it is clearly an arthritic joint

proves that we need enough lubricant for proper TMJ function

A

hyaluronate (HA)
different

proliferating

36
Q
TMJ Disorder (TMD):
•  A group of conditions that cause pain in the jaw joint and muscles, noises (clicking or crepitus) and restricted jaw movement.
•  10-30 million people/year in US, (F:M = \_\_\_\_)
Causes:
-  Trauma
-  Rheumatoid arthritis
-  Psycosocial – stress
-  Parafunctional activities, \_\_\_\_ 
-  \_\_\_\_ factor
-  Systemic joint \_\_\_\_
-  Unknown
A

2:1
bruxism
occlusal
laxity (flexible joint)

37
Q

TMJ and Facial Development

Abnormal facial development is observed in patients with
• Trauma to TMJ
• Developmental malformation of the ____
• ____

Juvenile idiopathic rheumatoid arthritis:
• ____ in age between 0-15 yrs; this number is actually under-estimated, in reality it is much higher
• Reports on TMJ involvement in JIA varies between 40-70%
• TMJ erosion is often associated with ____
• ____ joint in JIA
• Early ____ is necessary to prevent severe damage to
the TMJ and its consequences.

A

mandibular condyle
juvenile idiopathic rheumatoid arthritis (JIA)

1-1000
no pain
under-diagnosed
detection

38
Q

TMJ and Facial Development

  • ____
  • Limited mouth opening
  • ____ dysfunction
  • Occlusal cant/Facial asymmetry
  • ____
  • Breathing problem: ____
A

micrognathia (mandible)
jaw muscle
open bite
obstructive sleep apnea (OSA)

39
Q

Missing/smaller condyle? Suggestive of ____

A

arthritic TMJ