Skull, meninges and ventricular system Flashcards
What are the names of the 3 sutures of the skull?
Coronal, Saggital and Lambdoid
What is the neruocranium?
The neurocranium is a protective shell surrounding the brain and brain stem.
What is the viscerocranium?
The viscerocranium (or facial skeleton) is formed by the bones supporting the face.
What bones make up the neurocranium?
8 cranial bones: frontal, parietal (2), temporal (2), occipital, ethmoid and sphenoid
What bones make up the viscerocranium?
14 facial bones: nasal (2), lacrimal (2), inferior nasal concha (2), palatine (2), zygomatic (2), maxilla (2), mandible and vomer
What animal does the sphenoid bone look like?
Eagle
Describe the different parts the sphenoid bone is divided into.
The sphenoid bone is divided into several parts: the body of the bone, two greater wings, two lesser wings, and the pterygoid processes.
What are the four main regions of the temporal bone?
Squamous, Petrous, Mastoid process and Tympanic
What is the joint between the mandible and the cranium called?
Temporo-mandibular joint
Name a foramen in the mandible which is the entry point for one of the branches of the CN V3.
Mental foramen - the mental nerve (division of the Mandibular division of the trigeminal nerve) emerges from this foramen
Name the foramen in the mandible which the V3 nerve enters through.
Mandibular foramen
What is the Pterion?
The pterion: a ‘H-shaped’ junction between temporal, parietal, frontal and sphenoid bones. The thinnest part of the skull. A fracture here can lacerate the middle meningeal artery (anterior branch), resulting in a epidural haematoma.
What features are different between the neonatal and adult skull?
The stylomastoid formaen is vulnerable, no styloid or mastoid process. Some bones are not fused together and no teeth present.
How long does it take for the anterior fontanelle to close?
18 months
How long does it take for the posterior fontanelle to close?
3 months
What is the mnemonic to help remember the cranial foramen?
Old rotund owls spin lazily across jugs
What cranial nerves go through the jugular foramen?
IX, X and XI (Cranial nerves 9, 10 and 11 go through the jugular foramen) and the internal jugular vein
What structures are found in the foramen magnum?
Spinal cord and vertebral arteries
and accessory nerve (CN XI) enters skull here
What are the meningeal layers of the CNS?
Dura mater (Periosteal and Meningeal), Arachnoid mater and Pia mater
Extradural/epidural haematoma’s are caused by damage to which blood vessel?
Middle meningeal artery
Between which meningeal layers are subdural haematoma’s found?
Between the dura mater and arachnoid mater.
Between which meningeal layers are subarchnoid haematoma’s found?
Between arachnoid and pia maters. Usually due to cerebral artery damage.
What nerves innervate the dura?
Trigeminal nerve (V1, 2 and 3)
What are the falx and tentorium cerebri?
Double layered fold of the dura mater
Between which two meningeal layers does the dural venous sinus run?
Between the 2 layers of dura mater (periosteal and meningeal layer)
Name the various venous sinuses of the brain?
Superior sagittal, inferior sagittal, straight, transverse, sigmoid and cavernous sinus.
Where do the venous sinuses drain to?
Internal jugular vein
What lies medial to the cavernous sinus?
Sphenoid bone and pituitary fossa
What artery and cranial nerves go through the cavernous sinus?
CN III, IV, Va, Vb, and VI. Internal carotid artery
Where is CSF produced?
Ventricular system and circulates around the CNS
What does the CSF contain and what is its function?
CSF contains high sugar content (viscous) and it protects, nourishes the brain, cushions it and gives it buoyancy.
What connects the 3rd and 4th ventricles?
Cerebral aqueduct
What is the choroid plexus and its function?
The choroid plexus is a plexus of cells that produces the cerebrospinal fluid in the ventricles of the brain. The choroid plexus consists of modified ependymal cells. It lies in the lateral ventricles.
Why is some of the CSF reabsorbed in the dural venous sinus?
Due to the pressure dependent gradient
What would be the result of a blockage in the ventricular system?
Blockage can cause build up of CSF resulting in enlargement of the ventricles and hence cause HYDROCEPHALUS (increased intracranial pressure).
How is hydrocephalus different in babies and adults?
Can be dangerous in adults as skull provides no room for expansion and thus there can be a build up in intracranial pressure. However, in babies, there is room for expansion as the skull is not fused.
