Skull & Intracranial Region

• foramina of the skull

  
  

  what are the anatomical structures travelling through the skull foramina?


  here it shows what cranial nerves travel through what foraminas

  
• foramina of the skull

  
  

  what is the foramina of the skull?


  the narrow openings that allows the passage of nerves and blood vessels through the skull

  
• intracranial region: posterior cranial fossa

  
  

  what is the neuroanatomy of the posterior cranial fossa?

  ( what is located in this space?)

  - Brainstem and cerebellum

  - Sigmoid sinus

  - Cranial nerves VII-XII

  - Vertebral and basilar arteries
• intracranial region: posterior cranial fossa

  
  

  what bones form the boundary of the posterior cranial fossa?

  - temporal

  - occipital

  
• intracranial region: middle cranial fossa

  
  

  what is the neuroanatomy of the middle cranial fossa?

  ( what is located in this space?)

  - Temporal lobes

  - Cavernous sinus and associated cranial nerves

  - Optic nerves

  - Ophthalmic artery

  - Optic chiasm

  - Pituitary gland

  - Internal carotid arteries

  - Middle meningeal artery
• intracranial region: middle cranial fossa

  
  

  what bones form the boundary of the middle cranial fossa?

  - sphenoid (greater wings and body plus sinus)

  - petrous part of the temporal

  
• intracranial region: anterior cranial fossa

  
  

  what is the neuroanatomy of the anterior cranial fossa?

  ( what is located in this space?)

  - Frontal lobes of the brain

  - Olfactory nerves bulbs and tracts

  - Anterior cerebral artery
• intracranial region: anterior cranial fossa

  
  

  what bones form the boundary of the anterior cranial fossa?

  - Frontal

  - Ethmoid

  - Lesser wing of sphenoid

  
• intracranial region

  
  

  what are the three shallow depressions of the intracranial region?

  - anterior cranial fossa

  - middle cranial fossa

  - posterior cranial fossa

  
• intracranial region

  
  

  what is the intracranial region/cranial cavity?


  the space that contains the brain as well as the intracranial elements of both cranial and spinal nerves, blood vessels, meninges, and cerebrospinal fluid.

  
• the cervical vertebrae

  
  

  what are atypical cervical vertebrae?

  the first two vertebrae- atlas and axis.

  
  

  -> they are specialised to provide the greatest range of movement, both in the flexion/extension plane, as well as rotation

  
• the cervical vertebrae

  
  

  what are atypical vertebrae?
• the cervical vertebrae

  
  

  what are typical vertebrae?

  a vertebrae with the typical shape and structure
• the cervical vertebrae

  
  

  what is the role of the cervical vertebrae?


  provides a dual role:

  1 - weight support, relaying this force down to the lower vertebrae

  2 - head movement, through muscle action attached between the skull, cervical vertebrae and thora
• the cervical vertebrae

  
  

  what are the cervical vertebrae?

  The top seven vertebrae

  
• the cervical vertebrae

  
  

  what is the vertebrae?

  The individual bones of the spine are the vertebrae.

  -> there are the cervical, thoracic, lumbar, sacral, and coccygeal vertebrae

  
• the occipital condyle

  
  

  what is the occipital condyle?


  the distinctive bony structure linking the skull and the vertebral column

  - we have two occipital condyles that are located laterally to the foramen magnum, roughly the frontal half, on the under surface of the occipital bone

  
• skull air sinuses

  
  

  what are the four main skull air sinuses?

  - Frontal

  - Ethmoid

  - Sphenoid

  - Maxillary

  
• skull air sinuses

  
  

  what are the skull air sinuses?

  - air filled cavities

  - they lighten the weight of the head, humidify and heat inhaled air, and they contain mucus that drains to remove bacteria.
• facial bones

  
  

  describe the Mandible


  comprises the entire lower jaw. Its role is to supports the lower

  teeth and as anchor for the muscles of mastication

  
• facial bones

  
  

  describe the Inferior nasal conchae


  located in the lateral wall of the nasal cavity. Its

  superior and middle counterparts are part of the ethmoid bone, however the inferior are separate bones

  
• facial bones

  
  

  describe the Vomer

  makes the inferior posterior part of the nasal septum. Articulates with both the maxillae and the palatine bones. Its wings articulate superiorly with the sphenoid bone and the perpendicular plate of the ethmoid bone, forming together the bony nasal septum

  
• facial bones

  
  

  describe the Nasal

  form the bridge of the nose, with the lateral side articulating with the medial edge of the maxilla. Often fractured by blows to the nose

  
• Define the boundaries and describe the contents of the three cranial fossae
• facial bones

  
  

  describe the Lacrimal


  the smallest bones in the skull. Contribute to the medial wall of

  each orbit. These bones display a groove for the passage of the tear duct, which drains tears into the nasal cavity

  
• facial bones

  
  

  describe the Zygomatic

  commonly referred to as the cheekbones. Contribute to the

  lateral wall of each orbit and cheeks

  
• facial bones

  
  

  describe the Palatine


  small bones with a distinct L shape. Contribute to the hard palate, the nasal cavity and eye orbit

  
• facial bones

  
  

  describe the maxilla

  (paired bones) located centrally in the facial skeleton. Together the maxilla form the upper jaw supporting upper teeth

  
• facial bones

  
  

  what are the facial bones?

  - Maxilla

  - Palatine

  - Zygomatic

  - Lacrimal

  - Nasal

  - Vomer

  - Inferior nasal conchae

  - Mandible

  
• skull

  
  

  what are the adult skull sutures?

  - coronal suture

  - sagittal suture

  - lambdoid suture (resembles the greek symbol lambda; λ)

  
• skull

  
  

  what are the fontanelles in a foetal skull?

  soft spot spaces between the bones of the skull where bone formation is not complete.

  
  

  the foetal skull contains:

  1. Future coronal suture

  2. Anterior fontanelle

  3. Anterolateral fontanelle

  4. Future squamous suture

  5. Posterolateral fontanelle

  6. Future lambda suture

  7. External acoustic meatus

  8. Future sagittal suture

  9. Posterior fontanelle

  
• skull

  
  

  when do sutures fully close?

  Sutures do not fully close until after birth to prevent the thin bone from breaking. Also skull bones grow at this interface to match brain growth. Once growth is complete the skull bones become fully ossified.
• skull

  
  

  what do the bones of the skull articulate by?

  - sutures, which are almost rigid,

  or

  - movable joints such as the TMJ
• skull: Neurocranium

  
  

  what are key features of the ethmoid bone?

  - Crista galli anchors the falx cerebri

  - Lateral projections from the crista galli are the left and right cribriform plates that allow the passage of the olfactory nerves to the nasal cavity below

  - Inferior to the crista galli and running in the mid-sagittal plane is the perpendicular plate, which contributes in separating the left and right nasal passages

  - From each one of the Cribriform Plates there is a left or right Orbital Plate part of the medial wall of the respective eye orbit and origin of two medial projections, the superior and middle Nasal conchae

  
• skull: Neurocranium

  
  

  what are key features of the sphenoid bone?

  - The sella turcica ('Turkish saddle') encloses the pituitary gland

  - The Supra-Orbital Fissure separates the lesser wing superiorly from the greater wing below

  - The left and right greater wings form part of the posterior wall of each of the eye orbits (orbital plate)

  
• skull: Neurocranium

  
  

  what does the ethmoid bone cover?

  positioned between the orbits. This bone forms the anteromedial floor of the cranium, the roof of the nasal cavity, part of the medial wall of each orbit, and part of the nasal septum

  
• skull: Neurocranium

  
  

  what is the sella turcica of the sphenoid bone?

  a saddle-like feature of the sphenoid bone

  - it encloses the pituitary gland, which protrudes from the under surface of the brain

  - It is of clinical relevance given its confined space, whereby

  pituitary gland tumours can press on neighbouring structures

  such as the optic nerve

  
• skull: Neurocranium

  
  

  what does the sphenoid bone cover?

  shaped like a butterfly, this bone borders the cranial and facial

  skeleton. Articulates with every other cranial bone, as well as the palatine bones, zygomatic bones, maxillae and vomer

  
• skull: Neurocranium

  
  

  what does the temporal bone cover?

  cover the inferior lateral walls and part of the floor of the

  cranium. The term 'temporal' reflects the passage of time (i.e. grey hairs)

  
• skull: Neurocranium

  
  

  what does the occipital bone cover?

  (Latin 'occiput', which translates to 'back of the head') covers the posterior region of the skull