Skull, meninges and ventricular system

Question 1

What are the names of the 3 sutures of the skull?

Answer 1

Coronal, Saggital and Lambdoid

Question 2

What is the neruocranium?

Answer 2

The neurocranium is a protective shell surrounding the brain and brain stem.

Question 3

What is the viscerocranium?

Answer 3

The viscerocranium (or facial skeleton) is formed by the bones supporting the face.

Question 4

What bones make up the neurocranium?

Answer 4

8 cranial bones: frontal, parietal (2), temporal (2), occipital, ethmoid and sphenoid

Question 5

What bones make up the viscerocranium?

Answer 5

14 facial bones: nasal (2), lacrimal (2), inferior nasal concha (2), palatine (2), zygomatic (2), maxilla (2), mandible and vomer

Question 6

What animal does the sphenoid bone look like?

Answer 6

Eagle

Question 7

Describe the different parts the sphenoid bone is divided into.

Answer 7

The sphenoid bone is divided into several parts: the body of the bone, two greater wings, two lesser wings, and the pterygoid processes.

Question 8

What are the four main regions of the temporal bone?

Answer 8

Squamous, Petrous, Mastoid process and Tympanic

Question 9

What is the joint between the mandible and the cranium called?

Answer 9

Temporo-mandibular joint

Question 10

Name a foramen in the mandible which is the entry point for one of the branches of the CN V3.

Answer 10

Mental foramen - the mental nerve (division of the Mandibular division of the trigeminal nerve) emerges from this foramen

Question 11

Name the foramen in the mandible which the V3 nerve enters through.

Answer 11

Mandibular foramen

Question 12

What is the Pterion?

Answer 12

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.

Question 13

What features are different between the neonatal and adult skull?

Answer 13

The stylomastoid formaen is vulnerable, no styloid or mastoid process. Some bones are not fused together and no teeth present.

Question 14

How long does it take for the anterior fontanelle to close?

Answer 14

18 months

Question 15

How long does it take for the posterior fontanelle to close?

Answer 15

3 months

Question 16

What is the mnemonic to help remember the cranial foramen?

Answer 16

Old rotund owls spin lazily across jugs

Question 17

What cranial nerves go through the jugular foramen?

Answer 17

IX, X and XI (Cranial nerves 9, 10 and 11 go through the jugular foramen) and the internal jugular vein

Question 18

What structures are found in the foramen magnum?

Answer 18

Spinal cord and vertebral arteries

and accessory nerve (CN XI) enters skull here

Question 19

What are the meningeal layers of the CNS?

Answer 19

Dura mater (Periosteal and Meningeal), Arachnoid mater and Pia mater

Question 20

Extradural/epidural haematoma’s are caused by damage to which blood vessel?

Answer 20

Middle meningeal artery

Question 21

Between which meningeal layers are subdural haematoma’s found?

Answer 21

Between the dura mater and arachnoid mater.

Question 22

Between which meningeal layers are subarchnoid haematoma’s found?

Answer 22

Between arachnoid and pia maters. Usually due to cerebral artery damage.

Question 23

What nerves innervate the dura?

Answer 23

Trigeminal nerve (V1, 2 and 3)

Question 24

What are the falx and tentorium cerebri?

Answer 24

Double layered fold of the dura mater

Question 25

Between which two meningeal layers does the dural venous sinus run?

Answer 25

Between the 2 layers of dura mater (periosteal and meningeal layer)

Question 26

Name the various venous sinuses of the brain?

Answer 26

Superior sagittal, inferior sagittal, straight, transverse, sigmoid and cavernous sinus.

Question 27

Where do the venous sinuses drain to?

Answer 27

Internal jugular vein

Question 28

What lies medial to the cavernous sinus?

Answer 28

Sphenoid bone and pituitary fossa

Question 29

What artery and cranial nerves go through the cavernous sinus?

Answer 29

CN III, IV, Va, Vb, and VI. Internal carotid artery

Question 30

Where is CSF produced?

Answer 30

Ventricular system and circulates around the CNS

Question 31

What does the CSF contain and what is its function?

Answer 31

CSF contains high sugar content (viscous) and it protects, nourishes the brain, cushions it and gives it buoyancy.

Question 32

What connects the 3rd and 4th ventricles?

Answer 32

Cerebral aqueduct

Question 33

What is the choroid plexus and its function?

Answer 33

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.

Question 34

Why is some of the CSF reabsorbed in the dural venous sinus?

Answer 34

Due to the pressure dependent gradient

Question 35

What would be the result of a blockage in the ventricular system?

Answer 35

Blockage can cause build up of CSF resulting in enlargement of the ventricles and hence cause HYDROCEPHALUS (increased intracranial pressure).

Question 36

How is hydrocephalus different in babies and adults?

Answer 36

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.