Neurosurgery formative

Question 1

Where does the corticospinal tract originate?

Answer 1

Primary motor cortex in the precentral gyrus

Question 2

What are the 2 parts of the corticospinal tract and what are their functions?

Answer 2

• Lateral corticospinal tract (pyramidal decussation) - voluntary motor control of limbs and digits
• Anterior corticospinal tract (segmental decussation) - voluntary motor control of the trunk and maintains posture

Question 3

Where does the corticobulbar tract originate from?

Answer 3

Primary motor cortex in the precentral gyrus

Question 4

What is the function of the corticobulbar tract?

Answer 4

• Controls the muscles of face, head and neck (contains UMNs of cranial nerves)
• Bilateral innervation to cranial nerve nuclei except CN XII and lower part of CN VII

Question 5

Where is the lesion in Bells palsy?

Answer 5

Lower motor neuron of CN VII causing forehead and lip droop

Question 6

If there was an UMN lesion to CN VII e.g. stroke, how would that manifest itself in a patient?

Answer 6

Lip droop with forehead SPARING due to bilateral innervation

Question 7

What is the origin and function of the rubrospinal tract?

Answer 7

• Origin - red nucleus in the midbrain
• Function - excites flexor muscles and inhibits extensor muscles of the upper body

Question 8

What is the origin and function of the reticulospinal tract?

Answer 8

• Originates in the pons/medulla
• Function - excites extensors

Question 9

What are the features of decerebrate rigidity?

Answer 9

Plantar flexed, wrists and fingers flexed, forearms pronated, elbows extended and shoulders adducted

Question 10

What are the features of decorticate rigidity?

Answer 10

Plantar flexed, legs internally rotated, wrists and elbows flexed, arms adducted

Question 11

What is the function of the DCML pathway and where does it decussate?

Answer 11

• Function - responsible for fine touch, pressure and vibration
• Decussate in medulla to contralateral medial lemniscus to reach the primary somatosensory area in the postcentral gyrus

Question 12

What is the function of the spinothalamic tract and where does it decussate?

Answer 12

• Function - conveying pain and temperature
• Decussate segmentally in the spinal cord to reach the opposite primary somatosensory cortex

Question 13

A 30 year old man presented with a stab wound in his back. He has right sided weakness starting at T5 and left sided loss of pinprick sensation and temperature starting at T7. What spinal cord compression syndrome did this man develop?

Answer 13

Brown-Sequard syndrome

Question 14

A 39-year-old woman presented with severe headaches whenever she sneezed. She also had decreased sensation to pinprick over her upper back, shoulders, and upper arms. Her power in her arms was 2/5 but her lower body power was 5/5. What is the cause for patient’s sensation and motor weakness?

Answer 14

Syringomyelia

Question 15

Where do extradural haemorrhages originate and how do they present?

Answer 15

• Located between skull and dura
• Origin - arterial (middle meningeal artery)
• Presentation - mainly in young patients due to head trauma, lucid interval followed by unconsciousness

Question 16

How are extradural haemorrhages investigated and what would be the findings?

Answer 16

• CT scan
• Hyperdense BICONVEX lens appearance

Question 17

Where do chronic subdural haemorrhages originate and how do they present?

Answer 17

• Located between dura and arachnoid
• Venous origin (cerebral bridging veins)
• Presentation - older patients due to low impact trauma, progressive headache and confusion

Question 18

How are subdural haemorrhages investigated and what would be the findings?

Answer 18

• CT scan
• Hypodense CRESCENT shaped appearance

Question 19

Where do subarachnoid haemorrhages originate and how do they present?

Answer 19

• Located between arachnoid and pia
• Origin - arterial
• Presentation - due to severe head injuries or ruptured berry aneurysm
• Symptoms - severe thunderclap headache, meningeal irritation and loss of consciousness

Question 20

How are subarachnoid haemorrhages investigated and what would be the findings?

Answer 20

• CT scan initially, CT angiogram gives definitive diagnosis
• Hyperdense signal in the subarachnoid space

Question 21

What does cerebral herniation cause?

Answer 21

• Increased ICP due to any space occupying lesions
• Symptoms - extensor response, Cushing’s triad (hypertension, bradycardia and irregular breathing), unreactive pupil (uncal herniation)

Question 22

A patient presents unconscious with unilateral pupil mydriasis that does not constrict to light following a car accident. On CT, an intracranial hemorrhage with cerebral herniation. What is the most likely cause?

Answer 22

Uncal herniation

Question 23

A 66-year-old man presented with several falls over the course of the past few months. On examination, he had symmetrical weakness of his legs and mild weakness of his hand. He had an abnormal gait. His reflexes were extremely brisk in his legs with upgoing planters bilaterally. He has positive Hoffman’s sign. What is the most likely diagnosis?

Answer 23

Degenerative cervical myelopathy due to cervical spondylosis

Question 24

Label each of the arteries 1-9 (starting from top right and working anti-clockwise)

Answer 24

1 - middle cerebral 2 - ophthalmic 3 - internal carotid 4 - basilar 5 - vertebral 6 - posterior cerebral 7 - posterior communicating 8 - anterior cerebral 9 - anterior communicating

Question 25

What are the features of an anterior circulation stroke?

Answer 25

1. higher cerebral dysfunction e.g. **dysphasia** 2. **homonymous visual field defect** 3. **contralateral motor and/or sensory deficit of at least 2 areas** (out of face, arm and leg)

Question 26

What are the features of a posterior circulation stroke?

Answer 26

* **Cerebellar** dysfunction * **Isolated** homonymous visual field defect * **Cranial nerve dysfunction**

Question 27

What are the features of lacunar stroke?

Answer 27

A **pure motor or sensory stroke**

Question 28

What kind of stroke does this patient have? An 80-year-old ex-smoker with uncontrolled hypertension presented with the acute onset of numbness of his left arm and leg. On examination, there was decreased sensation to all his left side of the body and face.

Answer 28

Lacunar stroke

Question 29

What kind of stroke does this patient have? A 66-year-old female with atrial fibrillation presents with dysphasia and left hemiparesis

Answer 29

Partial anterior stroke

Question 30

What kind of stroke does this patient have? A 70-year-old male with left homonymous hemianopia. He has no other symptoms

Answer 30

Posterior circulation stroke

Question 31

Match the area of the brain corresponding with a lesion that would cause expressive dysphasia, receptive dysphasia and a lesion that would cause nystagmus, intention tremor and dysarthria respectively

Answer 31

* Expressive dysphasia - 2 (Broca's area) * Receptive dysphasia - 4 (Wernicke's area) * Nystagmus, intention tremor and dysarthria - 6 (cerebellum)

Question 32

Where is the primary auditory cortex found?

Answer 32

Superior temporal gyrus

Question 33

What controls the temperature of the body?

Answer 33

Hypothalamus

Question 34

What contains the oculomotor nucleus?

Answer 34

Midbrain

Question 35

Where would the tumour be found in this patient? A 7 year old boy presents with progressive headache, wide based ataxia and difficulty speaking. Imaging and biopsy confirms the presence of a pilocytic astrocytoma.

Answer 35

Cerebellum

Question 36

Where would the tumour be found in this patient? A 56-year-old man presented to the hospital with a seizure. He had been complaining of headaches for the past several months and has been “bumping into things”. On examination, it was revealed that he has a left superior quadrantopia. Imaging and biopsy confirmed a Glioblastoma multiforme

Answer 36

Right temporal lobe

Question 37

Where would the tumour be found in this patient? A 40 year old right-handed accountant presents with difficulty in writing and that he ”wasn’t as good with numbers as before”. On examination, he had a left-right disorientation. Imaging and biopsy confirmed the presence of a meningioma

Answer 37

Left parietal lobe

Question 38

What is the most likely cause of this patient's symptoms? A 6-month-old girl presented with a head circumference rising from the 66th to the 99th percentile and failure to thrive. On examination, when the lids are retracted, the eyes look like they are sunsetting, and upward gaze is impaired.

Answer 38

Non-communicating hydrocephalus due to aqueduct stenosis

Question 39

What is the most likely cause of this patient's symptoms? A 75 year old patient presents with a progressive shuffling gait and urinary incontinence. He denies any back pain. His wife is claiming that he has been forgetting his keys and taking his medication.

Answer 39

Normal pressure hydrocephalus

Question 40

What is the most likely cause of this patient's symptoms? A 56-year-old man presents with a headache, severity 8/10 with associated nausea. On examination he has ptosis, and miosis.

Answer 40

Internal carotid dissection

Question 41

What is the most likely cause of this patient's symptoms? A 56-year-old man presents with a progressive headache, severity 6/10 with associated nausea. On examination he has ptosis, and a right dilated unreactive eye.

Answer 41

Posterior communicating artery aneurysm

Question 42

What is the most likely cause of this patient's symptoms? A 56-year-old man presents with a headache, severity 10/10 with associated vomiting. On examination he has neck stiffness and photophobia.

Answer 42

Subarachnoid haemorrhage

Question 43

What is the most likely cause of this patient's symptoms? A 40-year-old obese lady on the contraceptive pill develops headaches first thing in the morning which are worse on coughing. She is complaining of double vision.

Answer 43

Sixth nerve palsy

Question 44

What is the most likely cause of this patient's symptoms? A 55 year old man develops diplopia after a closed head injury accident. He says the diplopia is worse when he is going down the stairs. On examination, you see he has a head tilt to the right.

Answer 44

Fourth nerve palsy

Question 45

What is the most likely cause of this patient's symptoms? A patient develops retro-orbital pain in his right eye described as a boring, worst pain he has ever felt, lasting 20 minutes. Associated tearing of that eye and a stuffy nose. He has 10 episodes of this pain for the past week.

Answer 45

Cluster headache

Question 46

A 30-year-old female presented with double vision and ataxia. Three years earlier she had an episode where she lost vision in her left eye for two weeks. On exam, she was mildly ataxic, with brisk reflexes, and both horizontal and vertical nystagmus. What is the most likely diagnosis?

Answer 46

Multiple sclerosis