Osteology of the Skull Flashcards
What are the 3 bones of the neonatal skull?
- Frontal
- Parietal
- Occipital
What separates the bones in the vault of the neonatal skull?
Sutures and fontanelles
What are the 3 sutures found in the neonatal skull?
- Coronal suture
- Sagittal suture
- Lambdoid suture
What are 3 fontanelles found in the neonatal skull?
- Anterior
- Posterior
- Small fontanelles on lateral aspect of the skull
What shape is the anterior fontanelle?
Diamond-shaped
At what age does the anterior fontanelle fuse?
One and a half years
What shape is the posterior fontanelle?
Triangular
At what age does the posterior fontanelle fuse?
One year
What are 5 ways fontanelles and sutures have clinical importance?
- Membranous articulations
- Brain enlargement
- Access to cranium
- Monitor pulse
- Depression is a sign of dehydration
What is the major difference between fontanelles and sutures?
Fontanelles are membranes and sutures are joints
What is the neurocranium?
Bones of the skull enclosing the brain
What is the viscerocranium?
Bones of the skull which make up the face
There are 11 major bones of the viscerocranium. Name them and mention which are paired
- Vomer
- Concha *
- Maxilla *
- Mandible
- Palatine *
- Zygomatic *
- Lacrimal *
- Nasal *
- Sphenoid
- Ethmoid
- Frontal
There are 6 major bones of the neurocranium. Name them and mention which are paired
- Frontal
- Parietal *
- Temporal *
- Occipital
- Sphenoid
- Ethmoid
How are bone processes named?
Whichever bone you are moving towards names the process e.g going from frontal bone to zygomatic is zygomatic process of frontal bone
What are 6 main features of the norma frontalis?
- Naison
- Glabella
- Superciliary arches
- Supraorbital margin
- Supraorbital foramina
- Infraorbital foramina
What are 3 features of the frontal bone?
- Superciliary arches
- Supraorbital margin
- Glabella
What are 4 features of the temporal bone?
- Superior and inferior temporal lines
- External acoustic meatus
- Mastoid process
- Styloid process
What are 2 features of the maxilla?
- Hard palate
2. Infraorbital foramen
What are 3 features of the occipital bone?
- Occipital condyle
- External occipital protuberance
- Superior and inferior nuchal line
What is bregma?
The area left when the anterior fontanelle has disappeared
What is lambda?
The area left when the posterior fontanelle has disappeared
What is the function of the occipital condyle?
Allows for articulation of skull with C1
What is the pterion?
Meeting of 4 bones:
Frontal, parietal, greater wing of sphenoid and temporal bone
What can a traumatic blow to the pterion cause?
Extradural haematoma
Why does an extradural haematoma occur at the pterion?
The middle meningeal artery runs underneath the pterion so can rupture the artery
Why is an extradural haematoma problematic?
The bleed is outside the meninges so can increase the pressure of the brain in the skull
What are the 3 divisions of the cranial cavity?
- Anterior cranial fossa
- Middle cranial fossa
- Posterior cranial fossa
What separates the anterior and middle cranial fossa?
Lesser wing of sphenoid
What separates the middle and posterior cranial fossa?
Petrous part of the temporal bone
What are 2 examples of sexual dimorphism with regards to the skull
- Male skulls are heavier
2. The forehead has more projected eyebrows as a result of larger frontal sinuses
