Clinically relevant anatomy of intracranial space occupying lesions & head trauma

Question 1

What are the layers of the scalp?

Answer 1

S- skin C- connective tissue A- aponeurosis L- loose connective tissue P- pericranium

Question 2

What is contained within the connective tissue layer of the scalp?

Answer 2

The named arteries of the scalp

Question 3

Describe the blood supply to the scalp

Answer 3

The common carotid artery branches into the internal and external carotid artery. Internal carotid artery –> right ophthalmic artery. External carotid -> scalp branches

Question 4

What is the protuberance of the skull?

Answer 4

External occipital protruberance

Question 5

What are the processes of the skull

Answer 5

Mastoid and styloid processes

Question 6

What is the pterion?

Answer 6

Thinnest part of the skull - H shaped Joins frontal, parietal, temporal and sphenoid bone

Question 7

Which artery courses deep to the pterion?

Answer 7

Middle meningeal artery

Question 8

Answer 8

Question 9

What are meninges?

Answer 9

Protective converings for the brain and spinal cord

Question 10

What are the three layers of the meninges?

Answer 10

Dura mater

Arachnoid mater

Pia mater

Question 11

Describe dura mater

Answer 11

Tough/fibrous

Has a sensory nerve suppy from CN V

Encloses the dural venous sinuses

Question 12

Describe the arachnoid mater

Answer 12

Spidery mother

Arachnoid granulations (reabsorb CSF)

Question 13

What is contained in the subarachnoid space?

Answer 13

CSF

Question 14

Describe pia mater

Answer 14

Adherent to the brain and the blood vessels and nerves entering or leaving brain

Question 15

What is tentorium cerebelli

Answer 15

Sheet of dura mater ‘tenting’ over the cerebellum

Attaches to the ridges of the petrous temporal bones

Has a central gap to permit the brainstem to pass through

Question 16

What is the diaphragm sellae

Answer 16

Tough sheet of dura mater forming a roof (diaphragm) over pituitary fossa

Question 17

What is the falx cerebri?

Answer 17

Midline structure

Made of dura mater

Attaches to deep aspect of skull

Separates right and left cerebral hemispheres

Question 18

What aspect of the skull does falx cerebri attach to anteriorly?

Answer 18

Crista galli of the ethmoid bone

Question 19

What aspect of the skull does the falx cerebri attach to medially?

Answer 19

Sagittal suture

Question 20

What aspect of the skull does the falx cerebri attach to posteriorly?

Answer 20

Occipital protruberance

Question 21

Describe the drainage of the brain

Answer 21

Question 22

Which arteries supply the brain?

Answer 22

vertebral artery

internal carotid

Question 23

Describe the arteries in the circle of willis and what they supply

Answer 23

Question 24

What is the volume of circulating CSF?

Answer 24

400-500mls

Question 25

Where is CSF produced?

Answer 25

Choroid plexus of the ventricles

Question 26

Where is CSF reabsorbed?

Answer 26

Dural venous sinuses via arachnoid granulations

Question 27

Where does the subarachnoid space end?

Answer 27

S2 part of spine

Question 28

where can CSF be accessed?

Answer 28

lumbar puncture at L3/L4 or L4/L5 IV disc levels to obtain a sample

Question 29

Describe the circulation of CSF?

Answer 29

1. secreted by choroid plexus in lateral and third ventricle 2. moves from left to right ventricles via foraminae of monroe 3. moves to the 3rd ventricle (midline) 4. then into the cerebral aqueduct 5. then into the 4th ventricle 6. then into the subarachnoid space or into the central canal 7. reabsorbed from subarachnoid space via arachnoid granulations 8. then into the dural venous sinuses

Question 30

What is hydrocephalus?

Answer 30

Excessive production, obstruction to flow or inadqeuate reabsorption of CSF leading to increased CSF volume

Question 31

Describe a ventricular peritoneal shunt

Answer 31

Shunt catheter is tunelled beneath the skino f the nect and chest then sited within peritoneal cavity

Question 32

Where does the circle of wilis lie?

Answer 32

Within the subarachnoid space

Question 33

What are the three kinds of bleeds within the cranial cavity?

Answer 33

Extradural haemorrhage Subdural haemorrhage Subarachnoid haemorrhage

Question 34

Describe an extradural haemorrhage

Answer 34

- between the bone & the dura - ruptured middle meningeal artery - trauma to the pterion

Question 35

Describe a subdural haemorrhage

Answer 35

- separates the dura from the arachnoid - torn cerebral veins - falls in the elderly

Question 36

Describe a subarachnoid haemorrhage?

Answer 36

- into the CSFof the subarachnoid space - ruptured Circle of Willis (“berry”) aneurysm - congenital aneurysm

Question 37

What are the kinds of supratentorial herniations

Answer 37

cingulate (subfalcine) Central (trans-tentorial) Uncal Transcalvarial

Question 38

What are the kinds of infratentorial herniations?

Answer 38

Upward cerebellar/transtentorial Downward cerebellar (tonsilar

Question 39

Which type of herniation leads to a blown pupil?

Answer 39

Compression of the oculomotor enrve by an uncal herniation leads to an ipsilateral fixed dilated pupil