Cranial nerves 1

How many pairs if cranial nerves that connect face, head and neck to brain?

12 pairs

What are the names of the 12 cranial nerves?

Identify where the cranial nerves are in the brain

Which cranial nerves are involved in somatic and special senses?

Which cranial nerves are involved in motor, voluntary movements of the skeletal muscles?

Which cranial nerves are involved in motor, autonomic / parasympathetic to smooth muscke and glands?

How do cranial nerves enter and exit the skull?

Describe the Olfactory (I) cranial nerve

• Sense of smell, pure sensory

• Olfactory receptirs in nasal mucosa

• Foramen: axons (olfactory filaments) pass through cribriform plate of the ethmoid bone

• Destination: olfactory bulbs underneath the brain & then via olfactory tracts to higher brain centres for conscious smell perception

• Can be ruptures by head injury causing loss of smell (anosmia)

What kind of nerve is the olfactory I nerve?

• pure sensory

• Sense if smell

Where are olfactory receptors?

In nasal mucosa

Where are the foramen for the olfactory I nerves?

Axons (olfactory filaments) pass through cribriform plate of ethmoid bone

Where is the destination of the olfactory I nerves?

• Olfactory bulbs underneath brain

• And then via olfactory tracts to higher brain centres for conscious smell perception

What can be happen if olfactory nerve damaged by head injury?

• Ruptures

• Causing loss of smell

Label the olfactory I nerve and tract

What kind of nerve is Optic (II) cranial nerve?

• Vision

• Pure sensory

What form the Optic II nerve?

Retinal ganglion cell axons

Where is the foramen of the Optic II nerve? Where does it continue to?

• Optic canal at the back if orbit

• Nerve continues as optic chiasm , then optic tract

Where is the destination if the Optic II nerve?

• Mainly lateral geniculate nucleus (LGN) if the thalamus (synapse)

• LGN axons then pass to the area if the brain responsible for conscious visual perception

• At the optic chiasm, nasal retina axons cross the midline , but temporal axons remain uncrossed

Describe the left and right visual hemi fields in the optic nerve , chiasm ans tract

What is an example of a visual fields affecting disease caused by damage to the axons at different optic pathway locations?

What are the eye movements of Oculomotor (III), Trochoear (IV), and Abducent ((VI) controlled by?

• Eye movements controlled by the 6 extraoccular muscles (EOMs) innervated by these nerves

Where are the oculomotor III, trochoear IV and abducent VI located?

Motor nuclei in the midbrain (III, IV) and pons (VI)

Where are the foramen of the oculomotor III, trochlear IV, and abducent VI?

Superior orbital fissure, back of orbit

How many EOMs dies the ocularmotor nerve supply and what are they?

4

• medical rectus

• Inferior rectus

• Superior rectus

• Inferior oblique

Which EOM does the trochlear supply?

Superior oblique

Which EOM does the abducent supply?

Lateral rectus

What can the 3rd oculomotor nerve also do?

• supply a voluntary muscke in the upper eyelid

• And has a parasympathetic component

Describe the actions if the EOMs in the primary gaze

• Lateral rectus ,, abduction out (6)

  
  

• Superior oblique ,, down and out (4)

• Suoerior rectus ,, up and in

• Inferior rectus ,, down and in

• Medial rectus ,, addiction in

• Inferior oblique ,, up and out

All by (3)

What is the mnemonic to remember which EOM Afro which cranial nerve?

• LR6 SO4

• Means lateral rectus is by 6 and superior oblique is by 4’ so the rest must be by 3

What can happen if you damage the 3 rd , 4th and or 6th cranial nerve?

What are simple tests for EOM and nerve function (ocular motility)?

What can halogen when there is damage to the 3rd cranial verve, ocularmotor nerve?

What happens when you damage the 4th cranial nerve, trochlear nerve?

What a hope a when you damage the 6th cranial nerve, abducent nerve?