H&N - Cranial Nerves
What mnemonic chart did Dr. Sumi give for cranial nerve components?
1. Remember the phrase --- SAVE VA SAVE VASE 2. Add 3 "S" and 4 "G" 3. My brother is 28yrs old 4. Lives in 51530 cross roads 5. He likes multiples of 12 and 11 6. Add three rows of 7;9 and 10
What 5 muscles (4 extrinsic eye mm.) are innervated by the oculomotor nerve? **
4 extrinisic eye mm.: 1) Superior rectus 2) Medial rectus 3) Inferior rectus 4) Inferior oblique Levator palpebrae superioris m.(elevates superior eyelid)
What embryonic pharyngeal arch gives rise to the trigeminal nerve?
Arch 1
What embryonic pharyngeal arch gives rise to the facial nerve?
Arch 2
What embryonic pharyngeal arch gives rise to the glossopharyngeal nerve?
Arch 3
What embryonic pharyngeal arches gives rise to the vagus nerve?
Arches 4 and 6
What are the 12 cranial nerves?
CN I - Olfactory CN II - Optic CN III - Occulomotor CN IV - Trochlear CN V - Trigeminal CN VI - Abducens CN VII - Facial CN VIII - Vestibulocochlear CN IX - Glossopharyngeal CN X - Vagus CN XI - Spinal Accessory CN XII - Hypoglossal
List the type of nerve each cranial nerve is (sensory, motor, or mixed/both).
CN I - Sensory CN II - Sensory CN III - Motor CN IV - Motor CN V - Both CN VI - Motor CN VII - Both CN VIII - Sensory CN IX - Both CN X - Both CN XI - Motor CN XII - Motor
Trace the path of the spinal accessory nerve.
Emerges with upper cervical spinal nerves (C1-C5). Ascends through *foramen magnum* Exits skull via *Jugular foramen* along with IX and X Branches innervate (Motor) Trapezius and SCM muscles
Trace the glossopharyngeal nerve***
Exit skull through *jugular foramen* Motor components to the tongue travel deep to the styloid process (good tag for lab), curving forward around the *stylopharyngeus muscle* Sensory to carotid travel posterior to pharyngeal constrictors
Trace the path of the vagus nerve.***
Exits skull via jugular Foramen Travels between the internal jugular V. and the internal carotid A. and descends in the carotid sheath The left curves under aortic arch and gives off left recurrent laryngeal. The right curves under subclavian and gives off right recurrent laryngeal.
Trace the path of the hypoglossal nerve
Exits the skull via the *hypoglossal canal* Runs medial to mandible and enters oral cavity Innervates (Motor) tongues muscles
What is the function of the oculomotor nerve?
Eye movement (4 of 6 eye mm.), Parasympathetic (constriction of pupil, movement of lens)
Which 2 cranial nerves exit the internal auditory meatus?***
Facial (VII) Vestibulocochlear (VIII)
Describe the pathway of the oculomotor nerve. ***
From the midbrain (interpeduncular fossa), the nerve travels through the *cavernous sinus* to enter the orbit via the Superior Orbital Fissure. It then travels through the *common tendinous ring*. From there, it branches to innervate 5 muscles
What are the four fiber types that can be found in *sensory* neurons?
GSA SSA GVA SVA
What nerve fiber types function to provide somatic sensation?
GSA (General Somatic Afferent)
What types of fibers compose the trigeminal nerve?
GSA (sensation to general face/tongue/sinuses/etc) SVE (muscles of mastication, MATT mm.)
What are the three fiber types that can be found in *motor* neurons?
GSE GVE SVE
What fibers make up the hypoglossal nerve?
GSE (general somatic efferent)
What nerve fiber types have somatomotor function, such as innervating skeletal muscles?
GSE (general somatic efferent)
What type of fibers make up the spinal accessory nerve?
GSE (general somatic efferent)
What fiber types compose the oculomotor nerve?
GSE (general somatic efferent) for 4/6 extrinsic eye muscles and levator palpebrae superioris GVE (general visceral efferent) for intrinsic eye muscles
What nerve fiber type functions to detect visceral sensations?
GVA (General Visceral Afferent)
What nerve fiber types have visceromotor function, such as innervation of the intraoccular muscles, salivary glands, heart, etc?
GVE (general visceral efferent)
What structures do the vestibulocochlear nerve pass through with the facial nerve?
Inferior pontine sulcus (lateral to facial n.) *Internal Auditory Meatus* (inferior to facial n.)
What are the 5 important nerves branch off the opthalmic division of the trigeminal nerve?
Lacrimal n. Nasalocilliary Frontal n.: (gives rise to the following 2 nerves) Supraorbital n. Supratrochlear n.
What muscle does the abducens nerve innervate?
Lateral Rectus (motor innervation) *so the abducens n. only innervates 1 eye m.
What are the 4 muscles that the trigeminal innervates as SVE that are not mm. of mastication?
MATT: mylohyoid anterior belly of digastric tensor tympani tensor veli palatini
What's the function of the spinal accessory nerve?
Motor innervation of Sternocleidomastoid and Trapezius muscles
What's the function of the hypoglossal nerve?***
Motor innervation of all of the muscles of the tongue EXCEPT for *Palatoglossus which is innervated by CN X*
What is one dirty mnemonic do you use to remember the 12 cranial nerves?
Oh Oh Oh To Touch A Female's Vagina Gives Vinny A Hard-on
What other dirty mnemonic helps to remember the cranial nerves? (don't judge me)
Oh- Olfactory Oh- Optic Oh- Occulomotor To - Trochlear Touch- Trigeminal And- Abducens Feel- Facial Virgin- Vestibulocochlear Girls- Glossopharyngeal Vaginas- Vagus And- Accessory Hymens- Hypoglossal
What is the function of the olfactory nerve?
Olfaction/smell
Trace the pathway of the olfactory nerve
Olfactory Receptors in Nasal Cavity (Sensory) transduce signal via the *Filia Olfactoria* through the *Cribiform plate* to the *Olfactory Bulb* (synapses). From the olfactory bulb, the information goes down the *Olfactory Tracts* to the *Cerebral Cortex*(synapses)
Trace the pathway of the optic nerve
Optic nerves (II) travel through the *optic canal* to form the *optic chiasm* as the join at the midline. Then, the *optic tracts* travel to the cerebrum
Describe generally the trigeminal nerve's pathway
Originate from the lateral surface of the Pons Sensory portion synapses in trigeminal Ganglion 3 branches emanate from the Ganglion to deliver sensory and motor innervation -Opthalmic Division (CNV1) via superior orbital fissure -Maxillary Division (CNV2) via foramen rotunda to pterygopalatine fossa and the infraorbital foramen -Mandibular Division (CNV3) via foramen ovale and mandibular foramen
Cranial nerves VII, IX, and X contain most fiber types. What types are they lacking?
SSA GSE
What nerve fiber types conduct impulses from retina, auditory and vestibular apparatuses?
SSA (Special Somatic Afferent)
What type of fibers compose the vestibulocochlear nerve?
SSA (special somatic afferent)
What nerve fiber types conduct gustatory (taste) and olfactory (smell) information to the brain?
SVA (Special Visceral Afferent)
What type of fibers constitute the olfactory nerve?
SVA (special visceral afferent)
What fibers constitute the glossopharyngeal nerve?
SVE GVE SVA (posterior 1/3 tongue) GVA (posterior 1/3 tongue, pharynx, mid sinus, parotid, carotid body) GSA (external auditory canal, part of auricle, tympanic membrane)
What nerve fiber types innervate skeletal muscles derived from the pharyngeal arches?
SVE (Special visceral efferent)
What fibers compose the vagus nerve?
SVE (muscles of Pharynx/larynx/soft palate except for stylopharyngeus and tensor veli palatini) GVE (thoracic and ab organs; guts to left of colic flexure) GVA (lower pharynx, all larynx, thoracic/ab viscera) SVA (taste around epiglottis) GSA (bit of auricle, external auditory canal, tympanic membrane)
What are the fiber types that compose the facial nerve?
SVE for muscles of facial expression GVE for lacrimal/palatal/submandibular/sublingual glands GVA for glands SVA for taste on anterior 2/3 tongue and soft palate GSA for part of auricle, external auditory canal, and tympanic membrane
Trace the path of the facial nerve***
Sensory and motor fibers exit the Internal auditory meatus (w/ CN VIII) and travel through the temporal bone. They synapse on the *geniculate ganglia* (synapses here), give off a branch, the *chorda tympani*, through the inner ear, and exit the skull via *styomastoid foramen*
What lurid mnemonic do you use to remember the nerve type for each cranial nerve?
Some Say Marry Money But My Brother Says Big Breasts Matter More
What type of fibers constitute the optic nerve?
Special somatic afferent
If you've got ipsilateral weakness of the shoulder and experience a shoulder shrug, what condition could be occuring?
Spinal accessory nerve palsy
What 3 muscles does the hypoglossal nerve innervate?
Styloglossus Hyoglossus Genioglossus
What muscle does the trochlear nerve innervate?
Superior oblique (motor innervation) *so the trochlear n. only innervates 1 eye m.
What nerve branches off the mandibular division of the trigeminal nerve, and why is it clinically important?
The inferior alveolar nerve (in mandibular canal) It is anesthetized when removing a tooth
Though cranial nerves III, IV, and VI all travel through the cavernous sinus, one of these does not enter the common tendineous ring. Which nerve does not?***
The trochlear nerve (IV)
What muscles does the spinal accessory nerve innervate?
Trapezius Sternocleidomastoid
What four cranial nerves are special visceral efferents?
Trigeminal nerve (V) Facial Nerve (VII) Glossopharyngeal (IX) Vagus (X)
What is the function of the optic nerve?
Vision
What is the function of the vestibulocochlear nerve?
sensory- balance/equilibrium and hearing
Give the function of the trigeminal n.
sensory- face, nasal, cavity, cheeks, lips, skin of mandible motor- mm. of mastication, anterior belly of digastric, mylohyoid
What's the function of the facial n.?
sensory- taste motor- facial mm., posterior belly of digastric parasympathetic- salivary glands and glands of nasal cavity
What's the function of the vagus n.?
sensory- taste, back of mouth, larynx, thoracic and abdominal organs motor- muscles of larynx, 1 muscle of tongue parasympathetic- thoracic and abdominal organs
What's the function of the glossopharyngeal n.?
sensory- taste, back of mouth, tonsils, middle ear motor- 1 muscle of pharynx parasympathetic- salivary gland, glands of tongue
What is the ONLY cranial nerve from the posterior brainstem?
trochlear n. (IV)
