Nerves Of Orbit: Sensory Nerve

Question 1

Sensory nerves (2)

Answer 1

1. Ophthalmic division of Trigeminal nerve
2. Optic nerve 2nd cranial nerve

Question 2

Ophthalmic division of Trigeminal nerve branches (3)

Answer 2

1. Nasociliary nerve
2. Frontal nerve
3. Lacrimal nerve

Question 3

Nasociliary nerve branches (4)

Answer 3

1. Two long ciliary nerves
2. Anterior ethmoidal nerve
3. Posterior ethmoidal nerve
4. Infratrochlear nerve

Question 4

Ophthalmic division of Trigeminal nerve course

Answer 4

Divides into 3 branches before entering orbit through superior orbital fissure

Question 5

Nasociliary nerve course

Answer 5

1. Carries ciliary ganglion
2. Enters orbit through medial part of SOF
3. Pass medial
4. Cross optic nerve
5. Reach orbit medial wall
6. Passes forwards giving its branches

Question 6

Two long ciliary nerves course

Answer 6

1. Run along optic nerve
2. Pierce eyeball back
3. Carry sympathetic fibers to dilator pupillae muscle

Question 7

Long ciliary nerves supply

Answer 7

Dilator pupillae muscle by sympathetic fibers

Question 8

Anterior ethmoidal nerve course

Answer 8

1. Passes via anterior ethmoidal foramen
2. Enter anterior cranial fossa
3. Passes to nasal cavity
4. Leaves as external nasal nerve

Question 9

Anterior ethmoidal nerve supply

Answer 9

Nasal cavity

Question 10

Posterior ethmoidal nerve course

Answer 10

Pass through posterior ethmoidal foramen

Question 11

Posterior ethmoidal nerve supply

Answer 11

Ethmoidal air cells

Question 12

Infratrochlear nerve course

Answer 12

Pass below torchea to eye medial angle

Question 13

Infratrochlear nerve supply (2)

Answer 13

1. Medial parts of eyelids
2. Nose root

Question 14

Frontal nerve course

Answer 14

Largest branch
1. Enters orbit through middle of SOF
2. Passes forwards below orbital roof and above Levator palpebrae muscle
3. Divides into 2 terminal branches

Question 15

Frontal nerve branches (2)

Answer 15

1. Supraorbital nerve
2. Supratrochlear nerve

Question 16

Frontal nerve supply

Answer 16

1. Skin of upper eyelid
2. Scalp anterior part

Question 17

Lacrimal nerve course

Answer 17

Smallest branch
1. Enters orbit through lateral end SOF
2. End in lacrimal gland
3. Receives twig from zygomaticotemporal branch of maxillary nerve containing secretomotor fibers to lacrimal gland

Question 18

Lacrimal nerve branch

Answer 18

1. Palpebral nerve

Question 19

Lacrimal nerve supply

Answer 19

Upper lid lateral 1/3

Question 20

Optic nerve

Answer 20

Axons of retinal ganglionic cells

Question 21

How does optic nerve differ from other cranial nerves

Answer 21

It is surrounded by extension of meninges which means it’s surrounded by subarachnoid space and CSF

Question 22

What causes optic disc edema (papilloedema)

Answer 22

Increase in intracranial pressure of optic nerve

Question 23

Optic nerve course

Answer 23

1. Leaves orbit
2. Enters cranial cavity through optic foramen
3. It partially decussates with nerve on the opposite side
4. Form optic chiasma