Radiological Neuroanatomy

Question 1

When is CT good for?

Answer 1

• Trauma + unstable patients
• Bleeding + stroke
• Bony injuries

Question 2

What is MRI good for?

Answer 2

• Soft tissues

- Fluid dark on T1, bright on T2

Question 3

Summarise the function and anatomy of the frontal lobe

Answer 3

• Primary motor cortex + neurons associated with STM, attention, planning + motivation
• In anterior cranial fossa
• Divided from…
  
  1. Each other by interhemispheric fissure
  2. Parietal lobes by central sulci
  3. Temporal lobes by sylvian fissures

Question 4

Summarise the function and anatomy of the parietal lobe

Answer 4

• Primary sensory cortex for touch, pain, temp + proprioception

Question 5

Summarise the function and anatomy of the occipital lobe

Answer 5

• Visual cortex
• Divided from…
  
  1. Parietal lobes anteriorly by parieto-occipital fissure
  2. Cerebellum inferiorly by tentorium cerebelli

Question 6

Summarise the function and anatomy of the temporal lobe

Answer 6

• In middle cranial fossa
• Dominant temporal lobe contains primary auditory cortex
• Involved in formation new memories + interpretation visual stimuli
• Divided from…
  
  1. Frontal + parietal lobes by sylvian fissures
  2. Cerebellum by tentorium

Question 7

Where is Broca’s area and what is its significance?

Answer 7

• Inferior frontal gyrus of dominant hemisphere - concerned with production of speech
• Problems = dysphasia
• Located left frontal lobe
• Left sided stroke = right sided weakness

Question 8

Where is the precentral gyrus and what does it contain?

Answer 8

• In posterior frontal lobe

- Contains primary motor cortex

Question 9

Where is the postcentral gyrus and what does it contain?

Answer 9

• Lies within anterior parietal lobe

- Contains primary sensory receptor area for sense of touch

Question 10

What does the amount of cortex devoted to body part proportional to?

Answer 10

Density of sensory nerve endings on body part

Question 11

Where is Wernicke’s area and what is it’s significance?

Answer 11

• Superior temporal lobe gyri

- Language comprehension

Question 12

Where is the role of the insular cortex?

Answer 12

• Perceptions, motor control, self-awareness + cognitive functioning
• One of the first areas visibly affected on imaging when middle cerebral artery stroke

Question 13

What makes of the basal ganglia?

Answer 13

• Caudate nucleus - memory + learning

- Lentiform nucleus

Question 14

What is the lentiform nucleus formed of?

Answer 14

Putamen

• linked to substantia nigra
• role in degenerative neurological disorders e.g. Parkinson’s
• regulate movements + influence various types of learning

Globus pallidus

• interna and externa
• involved in subconscious regulation movement

Question 15

What is the function of the thalamus?

Answer 15

• Through which signals sent between cerebral cortex + midbrain
• Regulation sleep + wakefulness
• Level of awareness + activity + processing
• Relaying sensory info to parts of cerebral cortex

Question 16

What is the external capsule?

Answer 16

Series of white matter tracts that run lateral to lentiform nucleus + connect diff areas of cortex

Question 17

What is the internal capsule?

Answer 17

• Series of white matter tracts split anatomically into anterior + posterior limb
• Connected by genu

Question 18

What is the corona radiata?

Answer 18

• Extension of internal capsule superiorly

- Carrying same ascending + descending tracts

Question 19

What is the circle of willis?

Answer 19

• Connect anterior + posterior arterial supply of brain
• Anterior circulation = anterior + middle cerebral arteries = internal carotid
• Posterior circulation - posterior cerebral arteries = basilar artery

Question 20

What are the most common areas for intracranial aneurysm?

Answer 20

• Anterior communicating artery
• Bifurcation of middle cerebral artery
• Posterior communicating artery
• Basilar tip

Question 21

What makes up the circle of willis?

Answer 21

ICA 
ACA = anterior cerebral 
MCA= middle cerebral 
PCA = posterior communicating 
PCA = posterior cerebral 
VA = vertebral 
BA
ACA = anterior communicating

Question 22

What does the middle cerebral artery supply?

Answer 22

Largest territory
Majority of lateral surface brain
Lentiform nucleus

Question 23

What does the anterior cerebral artery supply?

Answer 23

Medial strip of brain anteriorly

Question 24

What does the posterior cerebral artery supply?

Answer 24

Most of parietal lobe
Occipital lobe + inferior + medial parts temporal lobe
Thalamus

Question 25

Describe the drainage pathway of the superior sagittal sinus

Answer 25

> torcular herophili > transverse sinus > sigmoid sinuses > internal jugular veins

Question 26

Which ventricles are most superior on scanning?

Answer 26

Bodies of lateral ventricles

Question 27

What connects the lateral ventricle to 3rd ventricle?

Answer 27

Foramina of Monro

Question 28

Why is the size of the temporal horns important?

Answer 28

Can be enlarges due to hydrocephalus or appear enlarged due to hippocampal atrophy

Question 29

What connects the 3rd and 4th ventricle?

Answer 29

Sylvian aqueduct

Question 30

What arises laterally from 4th ventricle?

Answer 30

Foramina of Luschka

Question 31

What joins the 4th ventricle with foramen magnum

Answer 31

Foramen of Magendie

Question 32

What is the cerebellum divided into?

Answer 32

2 hemispheres | Each contain 3 lobes: anterior, posterior + vestibulocerebellum

Question 33

What are the hemispheres of cerebellum connected by?

Answer 33

Vermis

Question 34

What is the role of the cerebellum?

Answer 34

Coordination and timing of movements

Question 35

What effect can chronic alcohol intake have on the cerbelellum?

Answer 35

Atrophy

Question 36

What is the importance of the cerebellar tonsils?

Answer 36

1st structures to be squeezed through foramen magnum when coning occurs due to increased ICP

Question 37

What makes up the brainstem?

Answer 37

Midbrain Pons Medulla

Question 38

What does the midbrain contain?

Answer 38

- Corticospinal tract runs through cerebral peduncles | - Contains substantia nigra

Question 39

What does the pons contain?

Answer 39

- Tracts that link cerebrum to cerebellum | - Tracts that carry sensory signals to thalamus

Question 40

What is role of the medulla?

Answer 40

- Connects higher levels of brain to spinal cords - Autonomic functions - breathing, BP, HR - Reflex centres - vomiting, coughing, sneezing + swallowing

Question 41

What are the key features of a extradural/ epidural haemorrhage?

Answer 41

- Acute bleed - Trauma, head injury - Middle meningeal artery injury - Bioconvex shape - Does not cross structures - Head injury with lucid interval

Question 42

What are the key features of a subdural haemorrhage?

Answer 42

- Variable in age of bleed - No definite head trauma history - Tearing of bridging cortical veins - Crosses sutures but does not enter sulci - Crescent shape - CT appearance change with time - Hyperdense (acute) > Isodense to brain (subacute) > CSF density (chronic) - Reduced consciousness

Question 43

What are the key features of a subarachnoid haemorrhage ?

Answer 43

- Acute bleed - Traumatic (peripheral pattern) - Aneurysmal (central-suprasellar cistern pattern) - Blood in sulci and/or cisterns - may extend into ventricles - Normal CT does not exclude subarachnoid bleed - LP - Thunderclap headache, meningeal irritation signs

Question 44

What are the key features of a parenchymal haemorrhage?

Answer 44

- Acute bleed - Hypertensive, haemorrhagic transformation of acute infarct, trauma - Remember underlying malignancy - Within brain parenchyma, central may extend into ventricles - In trauma, contusions where brain impacts skull - peripheral blood - Older patient, hypertensive with neurological signs - Consider acute infections

Question 45

What is the quickest way to survey cervical spine?

Answer 45

Plain films 1. True lateral 2. AP view 3. Open mouth odontoid view

Question 46

What are hagman's fracture?

Answer 46

= fractures through pedicle of axis - Mechanism = hyperextension - Radiographic feature best seen on lateral view - Prevertebral swelling - Anterior dislocation of C2 vertebral body - Bilateral C2 pedicle fractures

Question 47

What is bilateral facet dislocation?

Answer 47

= complete anterior dislocation of vertebral body - Associated with high risk of cord damage - Mechanism = extreme flexion of head + neck without axial compression - Radiographic feature best seen on lateral view - Complete dislocation of affected body by half or more of vertebral body AP diameter - Bow tie or bat wing appearance of locked/ jumped facets