OCB04-2002 Skull & intracranial region Flashcards
What is the main function of the cranium?
Protects our brain and sensory organs
What are the two divisions of the cranium called?
Neurocranium and viscerocranium
What is the neurocranium made up of?
Skull cap (calvaria), cranial base, intracranial region
How many bones make up the neurocranium?
8
What are the singular bones of the neurocranium?
Frontal
Ethmoidal
Sphenoidal
Occipital
What are the paired bones of the neurocranium?
Temporal
Parietal
What is the viscerocranium made up of?
The facial bones in the anterior part of the cranium
What are the singular bones of the viscerocranium?
Mandible and Vomer
What are the paired bones of the viscerocranium?
Maxillae Inferior nasal conchae Zygomatic Palatine Nasal Lacrimal
What is the external part of the temporal bone called?
squamous part
What is the internal part of the temporal bone called?
petrous part
What is the pterion?
The joining of many bones in the skull- it is easily fractured
What is the smallest bone in the skull?
Lacrimal
Why is the sphenoid bone important?
It is the connection between the neurocranium and the viscerocranium
What is the function of the frontal bone?
Forms part of the top of the head, forehead and roof of the orbits
What is the function of the parietal bones?
Forms the lateral walls and roof of the cranium
What is the function of the occipital bone?
Represents the posterior region of the skull
What is the function of the temporal bones?
Forms the inferior lateral walls and part of the floor of the cranium
What is the function of the sphenoid bone?
Unites the cranial and facial bones
Articulates with every other cranial bone, palatine bones, zygomatic bones, maxillae and vomer
What is the function of the ethmoid bones?
Positioned between the orbits
Forms the roof of the nasal cavity, parts of the nasal septum, part of the medial wall of each orbit
What forms the nasal septum?
The perpendicular plate of the ethmoid bone and the vomer bone
What is the function of the maxilla bones?
they unite to form the upper jaw
What is the function of the palatine bones?
Form part of the hard palate, nasal cavity and eye orbit
What is the function of the zygomatic bones?
Cheekbones
Form the lateral wall of each orbit and cheeks
What is the function of the lacrimal bones?
Forms the medial wall of each orbit
Have a groove that provides a passageway for the tear duct, which drains into the nasal cavity
What is the function of the nasal bones?
Forms the bridge of the nose
What is the function of the vomer bone?
Forms the inferior part of the nasal septum
What is the function of the inferior nasal conchae bones?
located in the lateral wall of the nasal cavity
Creates turbulence in inhaled air
What is the function of the mandible bone?
Forms the entire lower jaw
What counter part of the conchae bone is not part of the ethmoid bone?
The inferior conchae bone
What foreman is for the entry of inferior alveolar nerve and vessels?
Mandibular foreamen
What foreman is for the emergence of the inferior alveolar nerve to supply the skin?
Mental foreamen
What are the articulations of the TMJ?
The head of the mandible articulates with the articular process of the temporal bone
What does a sinus cavity contain?
Air and mucus that drains out through them through the nose
What are the 4 main pairs of sinus cavities?
Frontal
Ethmoid
Sphenoid
Maxillary
What kind of joints are sutures?
Fibrous
How does the base of the skull articulate with the cervical spine?
Via the Occipital condyle
Which is the cervical vertebrae is the largest?
7th
How do thoracic vertebrae differ from cervical vertebrae?
Thoracic vertebrae do not have openings on the side, instead they have transverse processes
What are the 2 specialised cervical vertebrae?
Atlas (C1)
Axis (C2)
How do C1 and C2 vertebrae differ from other cervical vertebrae
They lack spinal processes
What is the top of the skull referred to?
Intracranial region
What is the bottom of the skull referred to?
Base of the cranium
What are the three cranial fossa?
Anterior
Middle
Posterior
What is the anterior fossa defined by?
Frontal bone
Ethmoid
Lesser wing of the sphenoid
What is the middle fossa define by?
Greater wing of the sphenoid
Petrous part of the temporal bone
What is the posterior fossa defined by?
Temporal and occipital bone
Why is the petrous part of the temporal bone so tough?
Protects the inner ear
What is the sella turcica?
A saddle-like prominence that holds and protects the pituitary gland
What two meninges can be seen by the naked eye?
Dura mater
Arachnoid mater
What important artery runs beneath the pterion that supplies the meninges?
Middle Meningeal artery
What is the main structure that passes through the foramen magnum?
Medulla/ spinal cord
What is the falx cerebri?
A fold of the dura mater in the longitudinal fissure that separates the cerebral hemispheres
What is the falx cerebelli?
It is a fold of the dura mater which separates the cerebellar hemispheres
What is the tentorium cerebelli?
An extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes
What is the dural venous sinuses?
Spaces between periosteal and meningeal layers of dura containing venous blood
Are valves present in the venous sinuses?
No
Where does blood originate from in the venous sinuses?
From the brain and cranial cavity and drains via the internal jugular vein
What is the circle of Willis?
The arterial blood supply to the brain
The arteries come from the internal carotid artery
What is embedded in the cerebral hemispheres?
Cerebral ventricles
What fluid fills the cerebral ventricles?
Cerebrospinal fluid
What are the two cerebral ventricles connected by?
the interventricular foramen
Where is CSF formed?
The choroid Plexus
How does CSF exit the ventricular system?
Via openings in the roof of the 4th ventricle into the sub-arachnoid space
What is hydrocephalus
Condition in newborns where there is a blockage of the flow of CSF, so there is increased inter cranial pressure
Brain becomes squashed ad ventricles become larger
Which part of the brain fits into the posterior cranial fossa?
Brainstem and cerebellum
Which cranial bone is closely associated with the cavernous sinus?
Sphenoid bone