Holoprosencephaly

Holoprosencephaly
Presentation by: Lindsay Higgins

Holoprosencephaly

* In holoprosencephaly, the prosencephalon fails to cleave down the midline, creating a single cerebral hemisphere and ventricle.
* The severity of holoprosencephaly is related to how completely the frontal regions of the brain are developed. The corpus callosum can be used as an approximate marker of brain development in holoprosencephaly. The further anterior the corupus forms, the better developed the brain.
* Three types: Alobar, Semilobar, and Lobar

Etiology of Holoprosencephaly
* Maternal Diabetes Mellitus
* Trisomy 13 (Patau Syndrome)
* Trisomy 18 (Edwards Syndrome)
* Fetal Alcohol Syndrome: Holoprosencephaly is the most severe manifestation of Fetal Alcohol Syndrome. It is especially associated with alcohol abuse during the first 4 weeks of pregnancy.
* Inherited mutations of genes HPE1, HPE2, HPE3, HPE4, HPE5
* Spontaneous mutations of Sonic Hedgehog Gene, which causes an autosomal dominant form of holoprosencephaly

Types of Holoprosencephaly
Alobar Holoprosencephaly
Semilobar Holoprosencephaly
Lobar Holoprosencephaly
References

Holoprosencephaly .ppt

Read more...

Craniofacial Aging Impacts on the Eigenface Biometric

Craniofacial Aging Impacts on the Eigenface Biometric
Presentation by:K. Ricanek Jr., E. Patterson, and E. Boone
University of North Carolina Wilmington
Wilmington, NC

Outline

* Craniofacial Aging
* Craniofacial Morphologic Data Corpus
* Face Biometrics
* Algorithms
o PCA
o PCA+LDA
o Bayesian ML
o Bayesian MAP
* Evaluation
* Results
* Conclusions

Craniofacial Aging
Craniofacial changes continue throughout adulthood.
Craniofacial Morphologic Data Corpus
MORPH Album1
Face Biometrics
Algorithms
Eigenface Biometric
Fisherface Biometric
Bayesian ML and MAP
Evaluation
Conclusions
Craniofacial Aging Impacts on the Eigenface Biometric.ppt

Read more...

Craniometry and Functional Craniology

Craniometry and Functional Craniology

Presentation by:
Michael S. Yuan, DDS, MA, PhD

Assistant Professor of Clinical Dentistry
Division of Orthodontics
School of Dental and Oral Surgery
Columbia University

Functional Craniology: Kinematics and Dynamics


Lecture outline

1. Introduction: definition, scope, and objectives
2. Kinematics and dynamics
3. Biomechanics: forces, deformation, stresses, strains
4. Form and Function
5. Bone remodeling and growth directions
6. Moss’ Hypothesis: Functional Matrix Hypothesis
7. Clinical applications

Functional Craniology


Dynamics
Kinematics
The description of measurement.
What is the true meaning of a measurement?
Force Compression, Tension, Shear, Bending, Torsion
Original status

Cranial Sutures

1. Edge-to-edge suture
* No force loading
2. Beveled suture
* Shear force [Squamosal suture]
3. Serrated suture
* Intermittent tension force
4. Beveled and serrated suture
* Intermittent tension and shear force
5. Butt-ended sutures
* Intermittent compressive force

1. Plane (gliding) joint
* Sliding motion of all directions
2. Hinge joint
* Flexion/extension

The Growth of Mandible
The Remodeling (Growth) Direction: The “V” Principle
Drift vs Displacement

Head (craniofacial complex) is a region, where a series of functions are carried out.
These functions include vision, hearing, speech, mastication, swallowing & digestion, respiration, neural integration, and others.
The successful execution of a function requires biomechanical protection and support.
Moss’ craniofacial growth theory:
Function of the craniofacial complex region is performed by the Functional Cranial Components (F.C.C).

Functional Matrix Hypothesis
Types of Functional Matrix
1. Orthodontics
2. Dentofacial Orthopedics and Orthognathic Surgery
3. Craniofacial surgery
Introduction: definition, scope, and objectives

Kinematics and dynamics
Biomechanics: forces, deformation, stresses, strains
Form and Function
Bone remodeling and growth directions
Moss’ Hypothesis: Functional Matrix Hypothesis
Clinical applications
References

Craniometry and Functional Craniology

Read more...

Theories of Craniofacial Growth

Theories of Craniofacial Growth
Presentation by:Mark H. Taylor, D.D.S., F.A.C.D.

What are the Causes
Theories of Craniofacial Growth

* Sicher's Theory
* Scott's Theory
* Moss' Theory
* Van Limborg's Compromise

Sicher's Theory

* Sutural dominance theory
* States that all skull tissue is controlled largely by its own intrinsic genetic information
* States that all bone forming elements are growth centers as opposed to growth sites
* This theory fails
* Examples:
* Microcephaly/Hydrocephaly
* Enucleation of the eye
* Damaged suture

Damaged Suture
Site of damage
Shift of sagittal suture
Normal rat skull
Experimental
rat skull

Scott's Theory

* Cartilagenous dominance theory
* States that cartilage and periosteum are growth centers and sutures are passive; this is largely not true
* Contribution was that Scott correlated sutural adaptation with growth of other tissues, such as synchondrosis growth

Synchondrosis Growth
Occipital
Sphenoid
Ethmoid
Frontal
Posterior cranial base
Anterior cranial base
Spheno-occipital
synchondrosis

Moss' Theory

* Moss denies any intrinsic regulatory control in the growing bony tissues
* Good theory, except for no intrinsic regulatory control
* Examples:
* rapid palatal expansion
* functional jaw orthopedics
* tongue volume vs. lower dental arch sizes (Tamari, et al, Am J Orthod Dentofac Orthop 1991; 100:453-8)

Van Limborg's Compromise
* Chondrocranial growth is controlled by intrinsic genetic factors
* Growth of the desmocranium (calvarium) is mainly controlled by many epigenetic factors (genetically determined influences originating from adjacent structures and spaces, such as brain, eyes, etc.)
* Growth of the desmocranium (calvarium) is influenced by local environmental factors (external environment such as local external pressure, muscle forces, etc.)
* Fails to classify the controlling factors for the mandible

A Modern Compromise

* Chondrocranium is the dominant factor in craniofacial growth
* Postnatal cartilage remnants - spheno-occipital synchondrosis (SOS) and nasal cartilage act as growth centers and are largely influenced by intrinsic genetic factors
* SOS exerts a direct action on the desmocranium, which is also dominated by brain expansion; sutures are growth sites or growth adjusters
* Nasal cartilage displaces maxilla downward and forward; functional matrix may also influence maxilla; orbits are dominated by functional matrix
* Mandible is dominated by local epigenetic and environmental factors (ex. 02 supply)
* cranial base growth alters position of glenoid fossa and therefore the position of the mandible
* nasal cartilage displaces the maxilla; therefore mandible is displaced

Theories of Craniofacial Growth.ppt

Read more...