Skull and Sockets Flashcards
Cranial bones
Facial bones
8 (cranial)
14 (facial)
Main cranial bones
Occipital bone 1 Parietal (2) Temporal (2) Frontal (1) Sphenoid (1) Ethmoid (1)
Main facial bones
Nasal (2) Zygomatic (2) Maxilla (2) Mandible (1) Vomer Conchae (2) Lacrimal (2) Palatine (2)
Primitive oral cavity is called
Stomodeum
Eye primitive
Optic Placode
Frontonasal prominence/ process
Nose, philtrum, forehead
Nasal/olfactory placode
Nose
Otic placode
Ear
Auricular hillocks
3 on arch 1
3 on arch 2
Forms the ear
6per ear
Week 5 nasal placode forms
Lateral nasal process and medial nasal process
Week 6 medial migration of frontonasal process
Lateral nasal and maxillary join and form nasolacrimal/nasooptic groove
Week 7 medial and frontonasal process form the
Philtrum
Week 7 medial and maxillary join to form
Upper lip
Week 10 nose and lip development
Medial process forms …
Philtrum
Medial Maxilla
Primary palate
Medial nose
Neurocranium made from
Encase the brain
Membranous neurocranium (flat bones) Cartilaginous neurocraium
Chondrocranium
Base of the skull
Neurocranium derm layers
From neural crest cell (ectoderm)
Somitomeres (mesoderm)
Viscerocranium cells
Face
Entirely neural crest cells (ectoderm)
Neural crest cells
Freely migrate and carry genetic code for development
Viscerocranium bones (9)
All neural crest cells: Facial bones Mandible Maxilla Zygoma Vomer Palatine Lacrimal Nasal Conchae
Neurocranium
Which cells make which bones
Neural crest cells: Temporal (squamosal) Sphenoid Ethmoid Frontal bones
Mesoderm:
Temporal (petrosal)
Occipital
Parietal
All bone are mesoderm except
Viscerocrainium Temporal Sphenoid Ethmoid Frontal bones Hyoids
Cartilage development starts at
Midline
Chondrocranium
Cranial base
Part occipital Ethmoid Sphenoid Temporal Meckel's cartilage
Intramembranous ossification
Absence of cartilage model
Flat bones of face and skull
Maxilla
Mandible
Clavicle
Endochondral ossification
Cartilage model precursor
Long bones Bones of extremities Vertebrae Ethmoid Sphenoid Chondrocranium (cranial base)
Embryonic bone development process
Intramembranous
Endochondral
Intramembranous ossification steps
- Mesenchymal cells proliferate
- Mesenchymal cells differentiate into osteoblasts secreting osteoid at multiple centers of ossification
3 osteoid is mineralized
Endochrondral ossification steps to
Hyaline cartilage model is used as a template
- Mesenchymal osteoblasts for two ossification centers
- Osteoid deposited in place of cartilage model
Usually ,make long bone
Epiphyseal cartilage has Distinct zones
5, for endochondral bone growth
Sutures and fontanelles
Allow for expansion for brain and allows for passage through the birth canal
How many fontanelles are there
6
Unfused sutures
How many bones does a newborn have?
44
Cranioschisis
Cranial vault does not form
Brain is fine
Craniosynostosis
Premature closure of one or more cranial sutures (suture fails)
Scaphocephaly
Craniosynostosis
Sagittal suture fails
Expansion of the frontal and occipital bone (long and narrow)
Brachycephaly
Craniosynostosis
Coronal sutures fails
Skull grows outward (stout skull)
Plagiocephaly
Craniosynostosis
Unilateral
coronal and lambdoid sutures
Asymmetric flattening of one side of skull
Cloverleaf skull
Craniosynostosis
Cloverleaf skull: most cranial sutures
