Cranial nerves

Question 1

Cranial nerves (where they originate from and their functions)

Answer 1

• Facial nerve (CNVII) goes through the internal acoustic meatus and then through the stylomastoid foramen into the face

Question 2

For cranial nerves I, II, III, IV & VI:

1. Where do they arise?
2. How they exit the base of the cranium?
3. Brief account of functions

Question 3

Case 1

After bumping her forehead into a door frame, 32-year-old Jenny entirely lost her sense of smell. This anosmia persisted the following day, prompting Jenny to visit her GP. The GP referred her to her local hospital for an MRI scan which revealed a contusion to her frontal lobe and a fractured ethmoid bone.

Which cranial nerve is likely to have been damaged?

Question 4

Case 2

Lucy has abducens nerve palsy after a brain tumour. What will her symptoms be?

Question 5

Case 3

Barry, a 68-year-old male, presents to his GP with a loss of visual acuity in his right eye. Following a head CT, a tumour was discovered to be compressing his optic nerve. Does this lesion exist anterior or posterior to the optic chiasm?

Question 6

Case 4

Following a recent blow to the head, Jasmine has noticed that her right eye is always looking slightly upwards and towards her nose, and that she is having to tilt her head a lot to see in a straight line.

Which of Jasmine’s cranial nerves has been damaged?

Why is her right eye elevated and adducted?

Question 7

Case 5

45 year-old Glynn has, over a period of several weeks, lost his lateral field of vision in both eyes. After arriving at his local hospital, he was sent for a head CT that revealed a pituitary tumour that was pressing on his optic chiasm, causing a condition known as bitemporal hemianopia.

Can you explain how this tumour is causing this specific problem?

Question 8

Case 6

Over the last few weeks, Jake, a 23-year-old shop assistant, has noticed his right upper eyelid beginning to droop significantly. At an appointment with his GP, a light was shone into his eye and the practitioner noticed that the pupil in his right eye was dilated compared to that of his left.

Is Jake suffering from Horner’s Syndrome or Oculomotor Nerve Palsy?

With reference to the eye, compare and contrast signs/symptoms that you might expect with CNIII palsy and Horner’s syndrome.