Oestology of the Skull Flashcards
What is the Anterior Fontanelle and where is it found?
Intersection of the inter-frontal, coronal and sagittal sutures. It is diamond-shaped
When does the anterior fontanelle disappear?
At one and half years of age
What are sutures?
They are an unossified membranous intervals that separate the bones of the vault
What is the posterior fontanelle and where is it found?
Lies at the intersection of the sagittal and lambdoid sutures and is triangular.
When does the posterior fontanelle fuse?
First year of life
Where are many small fontanelles found on the skull?
The lateral aspect
What is the clinical importance of fontanelles and sutures?
- Membranous Articulations/ molding during birth
- Allows brain development/ enlargement
- Access into cranium / Venus sinus/ ventricle
- Bulging : increased intracranial pressure
- Depression : dehydration
- Monitor Pulse
What is meant by the ventricle?
The cavity inside the cranium
When is the one time overlap of sutures occurs?
At birth
What is the importance of molding of the neonatal skull at birth?
Allow diameter of the skull to become smaller, therefore easier for baby to come out during natural birth
What would happen if there was dehydration of the skull?
Need to be hospitalised fro intravenous fluid
If there was assumptions of meningitis what would be done?
Inject into the anterior fontanelle and extract cerebrospinal fluid very easily
Name one difference in the size of the cranium between a newborn skull and an adult skull
Newborn skull has a disproportionately large cranium (portion enclosing the brain) relative to the face
What cause increase in length of the face?
Growth of the mandible, maxillary sinuses, and the alveolar process of the maxilla
What is meant by the neurocranium?
Bones enclosing the brain
What is meant by the viscerocranium?
Facial bones
List all the facial bones (viscerocranium)
Zygomatic bones Maxillae Nasal bones Lacrimal bones Vomer Palatine bones Inferior concha Mandible Sphenoid Ethmoid
List there facial bones which are paired
Zygomatic bones Maxillae Nasal bones Lacrimal bones Palatine bones Inferior concha
List all the facial bones that are single
Vomer
Mandible
Sphenoid
Ethmoid
Are the Zygomatic bones
paired or single?
Paired
Are the Maxillae bones paired or single?
Paired
Are the Nasal bones paired or single?
Paired
Are the Lacrimal bones paired or single?
Paired
Are the Vomer bones paired or single?
Single
Are the Palatine bones paired or single?
Paired
Are the Inferior concha bones paired or single?
Paired
Are the Mandible bones paired or single?
Single
Are the Sphenoid bone paired or single in the viscerocranium?
Single
Are the Ethmoid bones paired or single in the viscerocranium?
Single
What is the nasal bone paired?
It has a suture
What is the vomer bone part of?
The nasal septum
List the bones that form the neurocranium
Single Frontal Paired parietal Paired temporal Single Occipital bone Single Sphenoid bone Single Ethmoid bone
How many cranial bones are there?
8
List all the single bones that form the neurocranium
Single Frontal
Single Occipital bone
Single Sphenoid bone
Ethmoid bone
List all the paired bones that form the neurocranium
Paired parietal
Paired temporal
What are the features of the Norma Frontallis?
Nasion
Glabella
Supercilary Arches
Supraorbital margin
What are the foramina in the norma frontalis?
Supraorbital
Infraorbital
What is found within the frontal bone?
Superciliary arches
Supraorbital margin
Glabella
What is found within the zygomatic bone?
Temporal process of zygomatic bone
What is found in the temporal bone?
Zygomatic process of temporal bone Superior and inferior temporal lines External acoustic meatus Mastoid process Styloid process
What is found in the maxilla?
Hard Palate
Infraorbital fporamen
What is found in the occipital bone?
Occipital condyle (projection inside)
External occipital protuberance
Superior nuchal line
What is the name for the large projection behind the ear?
Zygomatic process
Where is the pterion found?
2.6cm behind and 1.3cm above the frontozygomatic suture
What vessel runs along the pterion? Where is it found?
Anterior division of the middle meningeal artery
Runs underneath the pterion
Found outside the duramater
State the consequence of a traumatic blow (perhaps car crash) to the pterion?
The middle meningeal artery could rupture as it passes very close to the pterion. This can cause internal bleeding and an extradural haematoma.
List the 3 divisions of the interior base of the skull
Anterior cranial fossa
Middle cranial fossa
Posterior cranial fossa
What separates the anterior cranial fossa from the middle cranial fossa?
The lesser wing of sphenoid
What separates the middle cranial fossa from the posterior cranial fossa?
Petrous part of the temporal bone
State differences between male and female skulls
- Male skulls are heavier
- Forehead is beetle-browed
What causes men to have more projected eyebrows (beetle-browed forehead)?
The frontal sinuses are larger and form more prominent superciliary arches externally
