Cranial nerves

Question 1

What are the mnemonics to memorize cranial nerves?

Answer 1

1. Only Optimistic Octopus Tentacles Try And Feel Very Good Vaginally Accessible Hymen

I = olfactory 
II= optical 
III -oculomotor 
IV= trochlear 
V = trigeminal 
VI= abducens 
VII = facial, 
VIII =vestibulocochlear
IX = glossopharyngeal
X = vagus 
XI = accessory 
XII = hypoglossal

Question 2

For the cranial nerves, which are sensory, motor or both?

Answer 2

Sensory
----
I -Olfactory (smell) 
II - Optic (vision)
VIII - Vestibulocochlear (hearing/sense of balance) 

III - oculomotor - move most muscles of the eye (orbit)
VI -Abducens - only muscles that abduct the eye
IV - Trochlear - only one muscle of the eye which acts like a pulley
XI - accessory - moves the trapezius muscles + sternocleidomastoid
XII - hypoglossal - found below the tongue and assist in tongue movement

1. Trigeminal - V : sensations of opthalmic, mandubular and maxillary divisions + mastication
2. Facial - VII: TASTE, go to tongue
   Parasympathetic: salivary glands and make tears
   Motor: facial expressions, innervate small muscles that attach to skin.
3. Glossopharyngeal - receives general somatic sensory information from tonsils, pharynx, middle ear and TASTE from posterior one third of tongue
   -innervates the styolpharyngeus muscle (only motor)
   Parasympathetics: salivary gland
4. Vagus - X - its preganglionic parasympathetics only have to do with thorax and gut, no parasympathetics in head and neck.
   -gets striated muscles in the larynx important for sensation

Question 3

What is the course of the mandibular division of the trigeminal nerve?

Answer 3

The whole course goes through three different openings.

Trigeminal nerve starts in the middle cranial fossa
> foramen ovale (opening)
>infratemporal fossa –trigeminal divides 5 times
>one division, the inferior alveolar nerve (sensory for teeth, toothache)
> mandibular foramen
>goes through mandibular bone and exits an opening on the chin - mental foramen
>when it passes this opening, inferior alveolar nerve = mental nerve