Skull Flashcards
Name the 4 main cranial bones
Occipital (1)
Parietal (2)
Temporal (2)
Frontal (1)
Name the 4 main facial bones
Nasal (2)
Zygomatic (2)
Maxilla (1)
Mandible (1)
Describe the eye development in the 4th - 10th week
Optic placode forms, moves anteriorly, and then to the front of the face
Describe the ear development in the 4th - 10th week
3 auricular hillocks form from Pharyngeal Arch 1, and 3 form from Arch 2
Auricular Hillocks and External Auditory Meatus migrate to Otic Placode
Hillocks and meatus join to form the ear
Describe the nasal development in the 5th -10th week
Nasal Placode forms the lateral nasal process & Medial nasal process
Medial migration of frontonasal process, Lateral nasal & Maxillary join form Nasolacrimal/Nasooptic groove
Medial process forms Philtrum, medial Maxilla, Primary Palate, medial nose
Describe the lip development around the 7th - 10th week
Medial & Fronto Nasal process form the Philtrum
Medial and Maxillary join to form upper lip
Name the two components that make up the skull
Neurocranium and Viscerocranium
What is the broad definition of the neurocranium?
Bones that encase the brain
What is the broad definition of the viscerocranium
Facial bones
What are the two type of neurocranium?
Membranous
Cartilaginous
Name the bones that are derived from the mesoderm in the neurocranium
Parietal, Temporal (Petrosal area), Occipital
What type of cells carry with them the genetic code for development? Are these cells found in the Neurocranium or Viscerocranium?
Neural Crest Cells
Found in both
True or False
The Viscerocranium contains such bones as the Facial Bones, Mandible, Maxilla, Zygoma, Vomer, Palatine, Lacrimal, Nasal, Conchae
True
True or False
The bones derived from the mesoderm in the neurocranium contains such bones as the Temporal (squamosal), Sphenoid, Ethmoid, Frontal bones
False
These are the bones originating from neural crest cells
True or False
The Viscerocranium contains only bone originating from neural crest cells
True
Note: The Neurocranium has both mesoderm and neural crest
What are the types of ossification?
Intramembranous
Endochondral
Which type of ossification relies on cartilage formation?
Endochondral
Describe intramembranous ossification
Mesenchymal cells aggregate and proliferate.
Mesenchymal cells differentiate into Osteoblasts and secrete osteoid at multiple centers of ossification.
Osteoid is mineralized.
Meckel’s cartilage is an example of which type of ossification?
Intramembranous
What bones are formed by intramembranous ossification?
Flat bones of face and skull, mandible, clavicle
Describe endochondral ossification
A hyaline cartilage model is used as a template during the generation of long and short bones
Mesenchymal osteoblasts for 2 ossification centers
Osteoid deposited in place of cartilage model
Endochondral bone growth depends on the presence of ________.
This growth begins in the second trimester and continues into ___________
Epiphyseal cartilage
Early adulthood
What is the purpose of sutures and fontanelles?
To provide flexibility/compression through the birth canal and to allow for rapid brain development
What is Cranioschisis?
Cranial vault fails to form
What is Craniosynostosis?
Premature closure of one or more cranial sutures
What are the 4 examples of craniosynostosis?
Scaphocephaly (long front to occipit)
Brachycephaly (short front to occipit)
Plagiocephaly (unilateral flattening)
Clover Leaf Skull (most sutures closed)
FGF’s and their receptors are involved in _______
Bone formation (especially cranial bones)
