Neuroanatomy

Question 1

What is white and black in a T1 vs T2 weighted MRI?

Answer 1

T1: CSF is black, fat is white
T2: Water is white, fat is white

Question 2

What is the most inferior ventricle?

Answer 2

4th ventricle

Next to cerebellum

Question 3

What is the space between lateral ventricle and 3rd ventricle called?

Answer 3

Foramen of monro

Question 4

What is the junction between the occipital and parietal bones called?

Answer 4

Lambdoid suture

Question 5

What is the junction between the two parietal bones called?

Answer 5

Sagittal suture

Question 6

What is the junction between the parietal and frontal bones called?

Answer 6

Coronal suture

Question 7

Where is the cerebral aqueduct?

Answer 7

Between 3rd and 4th ventricles

Question 8

When do you get an incomplete ptosis?

Answer 8

Horner syndrome

Only smooth muscle impaired, skeletal muscle still in tact

Question 9

What is the only motor function of the trigeminal nerve?

Answer 9

Mastication

Masseter, temporalis, pterygoids

Question 10

What muscles are supplied by the radial nerve?

Answer 10

Posterior compartment of arm (triceps)

Posterior compartment of forearm (extensors)

Question 11

What skin is supplied by the radial nerve?

Answer 11

Posterior arm and forearm
Lateral ⅔ of dorsum of hand
Proximal dorsal aspect of lateral 3½ fingers (thumb, index, middle and half of ring finger)

Question 12

What happens when radial nerve is injured

Answer 12

Wrist drop
Wasting of triceps (loss of reflex?)
Weak elbow and wrist extension

Question 13

What muscles are supplied by the median nerve?

Answer 13

Most anterior forearm muscles (flexors, pronator)

Thumb side intrinsic hand muscles

Question 14

Sensory supply of median nerve

Answer 14

Skin over thenar eminence
Lateral ⅔ palm of hand
Palmar aspect of lateral 3½ fingers
Dorsal fingertips of lateral 3½ fingers (thumb, index, middle and half of ring finger)

Question 15

Common injury of median nerve

Answer 15

Carpal tunnel

Wrist lacerations

Question 16

What happens when the median nerve is injured?

Answer 16

Weak forearm pronation, wrist flexion and abduction, and weak finger flexion with preservation of DIPJ flexion at ring and little fingers
Weak thumb opposition

Question 17

Sensory supply of ulnar nerve

Answer 17

Skin over hypothenar eminence
medial ⅓ palm and dorsum of hand
palmar aspect of lateral 1½ fingers
dorsal aspect of medial 1½ fingers (little finger and half of ring finger)

Question 18

Motor supply of ulnar nerve

Answer 18

2 anterior forearm muscles

Most intrinsic muscles of hand

Question 19

What happens when ulnar nerve is injured?

Answer 19

Cannot extend ring finger and little finger (claw hand)

wasting of hypothenar eminence and intrinsic muscles of hand

Question 20

What does the femoral nerve split into?

Answer 20

Saphenous, tibial and common fibular (peroneal) nerve

Question 21

Cause of painful 3rd nerve palsy is__

Answer 21

PCA aneurysm until proven otherwise

Question 22

Difference between UMN and LMN facial nerve palsy

Answer 22

UMN palsy spares upper part of the face (bilateral innervation). LMN is complete paralysis of one side of the face.

Question 23

Where are the cranial nerve nuclei found?

Answer 23

Floor level of medulla: 10/11/12
Pons: 5,6,7
Midbrain:3/4
CNII is part of CNS, all other CN are PNS

Question 24

What is seen in cervical artery dissection?

Answer 24

• Fried egg sign on CT/MRI
• Horner’s syndrome/Compression of lower cranial nerves
• Unilateral ipsilateral headache
• Retinal ischaemia/cerebellar ischaemia
• Traumatic or spontaneous, esp in young patients
• Treated with antiplatelets

Question 25

Where do the parasympathetic fibres run for pupillary constriction?

Answer 25

With CN III

Question 26

What is the afferent nerve for gag reflex?

Answer 26

IX (glossopharyngeal)

Question 27

What is the normal plantar reflex? When is abnormal seen?

Answer 27

Normal is downgoing (flexion)

Abnormal is extension of big toes (UMN lesion)

Question 28

What does the femoral nerve supply?

Answer 28

Sartorius

Quadriceps

Question 29

What does the sciatic nerve supply?

Answer 29

Hamstrings (semitendinosus/membrinosus, biceps femoris)

Adductor magnus

Question 30

What does the obturator supply?

Answer 30

Obturator externus
Adductors
Gracilis

Question 31

What does the tibial nerve supply?

Answer 31

Tibial nerve comes from femoral n.
Supplies posterior calf (gastroncnemius, plantaris)
Tibialis posterior
-> plantar nerve in foot

Question 32

What does the common fibular nerve supply?

Answer 32

Fibularis muscles
Tibialis anterior
Extensors

Question 33

Where is dermatome C7?

Answer 33

Middle finger

Question 34

Where is dermatome C5?

Answer 34

Over deltoid and lateral upper arm

Question 35

Where is dermatome T2?

Answer 35

Armpit

Question 36

Where is dermatome S3?

Answer 36

Bum

Question 37

Where is detmatome S1?

Answer 37

Under foot

Question 38

Which dermatome is front of knee?

Answer 38

L3

Question 39

How can intracranial pressure be measured?

Answer 39

Intraparenchymal fibreoptic catheter
Epidural transducer
Subdural catheter
Subdural bolt

Question 40

Emergency treatment of raised ICP

Answer 40

• Head up: encourage venous return, CSF gets absorbed faster from arachnoid granulations
• Ventriculostomy: ventricular drain to drain CSF
• Mannitol
• Decompressive craniectomy
• Sedate and paralyse them, to decrease the metabolic activity of the brain.
• Cool them down, decrease metabolic activity in the brain.
• Seizure control
• Evacuation of clot

Question 41

How is an intracranial abscess diagnosed?

Answer 41

DWI shows restriction of diffusion due to presence of a capsule

Question 42

How quick do nerves grow?

Answer 42

1mm/day