Flashcards in Session 2 Deck (42):
What bones meet at the Pterion?
What is clinically important about the Pterion?
It is the weak point of the skull so is more likely to fracture in trauma
Location of a branch of the middle meningeal artery which can bleed profusely
Which are the typical cervical vertebrae?
What are the atypical cervical vertebrae?
C1, C2, & C7
What are some of the properties of a typical cervical vertebrae?
Bifid spinous process
Vertebral/Transverse foramen for vertebral artery
Large middle foramen for the many nerves exciting the brain
What are the properties of C1? (Atlas)
No spinous process
Does the movement of yes
What are the properties of C2? (Axis)
Bifid spinous process
Has adeontoid peg (Dens)
Does the movement of no
Is there an intervertebral disc between C1 & C2?
What prevents the dislocation of the dens into the spinal cord?
The posterior spinal ligament becomes the cruciform ligament in this area. This gives major reinforcement over the dens process.
What are the properties of C7?
Prominent spinous process that is NOT bifid
Large transverse process
What is a Burst (Jefferson) fracture?
Usually happens to C1
The patient falls on their head from a height resulting in the vertebrae breaking
What is a Hangman's fracture?
The Atlas is snapped so the dens pushes into the spinal cord resulting in death..
It is caused by hyperextension of the head on the neck
How many cranial nerves are there?
8 cranial nerves (First one exits above C1)
What is the only movable joint of the skull?
The Temporo-mandibular joint (Bilateral movement)
What are most of the joints of the skull?
Symphises/sutures (Fibrous joints)
What bones usually house the brain?
What is the major opening in the skull?
The foramen magnum which is on the inferior of the skull
What increases the strength of the sutures of the skull?
The bones have serrated edges so they can interlock firmly. This makes them stronger and less likely to be unlocked by forced applied in one direction
What is the structure of the bones making the skull?
Tri-lamina bony structure (2 plates of compact bone with 1 middle layer of spongy bone called Diploe)
Which bones of the skull are thickest?
*Due to many muscles attaching here*
Which bones are the skull are thinnest?
*Lots of muscles here*
What are some of the cavities of the skull?
What makes the Mandible?
The left and right mandible are joined at the midline by a fibrous joint called the mental symphises
What is the Calvaria?
Houses the brain
Made of cap and base
What bones make the cap of the Calvaria?
What is the Coronal suture?
In the anterior part of the skull. Between the frontal and parietal bones of the skull
What is the Bregma?
Where the Coronal suture meets the Longitudinal suture
What is the Lambdoid suture?
In the posterior part of the skull. Between the Parietal and Occipital bones of the skull
What is the Lambda?
Where the Lambdoid suture meets the Longitudinal suture
What is at the posterior of the cap?
A foramina for the emissary veins
What bones make the Cranial floor?
How many fossa are there in the cranial floor?
What is the purpose of cranial floor fossas?
Make the skull lighter
Allow things to pass in and out of the skull
*However, can fracture when there is an increase in energy input*
What enters the cranial cavity?
Arterial supply to brain and meninges
Sympathetic fibres from the spinal cord
Venous blood (*Route for infection*)
How is the frontal bone formed?
The left and right frontal bones fuse
How can a fracture of the Ethmoid bone lead to a loss of smell?
The Olfactory nerves pass through it so can be damaged when there is a frature
What are the 2 cell types in the Ethmoid sinuses?
Bulla - Bigger buldges
What is the strongest bone in the body?
The Temporal bone
What are the 6 parts of the Temporal bone?
Petroud part (Seen when looking at inside)
What is a Fontanelle?
Soft membranous gaps between the incompletely formed cranial bones of an infant. In position of the Bregma and Lambda in adults
What is the importance of Fontanelles?
Close during vaginal birth due to pressure - protects the brain
Allow the brain to grow quickly without restriction