Cranial Nerves VI - XII Flashcards
What is the 6th cranial nerve and describe its route
Abducent nerve
Hind brain b/w Pons and Medulla Oblongata –> Cavernous Sinus –>
Sup. Orb. Fissure –> Lateral Rectus muscle
Whats the clinical test for the abducent nerve
lateral eye movement
What can be the effects of damage to the abducent nerve
inability to rotate eye laterally; at rest – eye rotates medially
Which nerves innervate which parts of extra ocular movement
Abducens (6) - lateral rectus muscle, moves eye laterally
Trochlear (4) - superior oblique muscle, moves eye down and rotates internally
Oculomotor (3) - all other eye muscle movement, also raises lid and mediates pupillary constriction
What is the 7th cranial nerve and describe its route
Facial
Hind brain –> Internal Acoustic Meatus –> Geniculate nucleus –> Stylomastoid foramen –> Parotid gland
What are the branches of the facial nerve
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
What is the chordates tympani
nerve of the facial nerve that joins the lingual division of the mandibular nerve
What is the greater petrosal nerve
Branch of facial
innervates lacrimal gland and taste buds on anterior part of palate
What is the function of the facial nerve
facial expression; sense of taste
What is the clinical test for the facial nerve
motor functions – close eyes, smile, whistle, frown, raise eyebrows; taste
What can be the effects of damage to the facial nerve
inability to control facial muscles; distorted sense of taste, dry eyes
What is the 8th cranial nerve and describe its route
Vestibulocochlear
Hind brain –> IAM –> Vestibular and cochlear fibres
What is the function of the vestibulocochlear (8th) nerve
hearing and equilibrium
What are the clinical tests for the vestibulocochlear (8th) nerver
test hearing, balance, and ability to walk a straight line
What can be the effects of damage to the vestibulocochclear (8th) nerve
deafness, dizziness, nausea, loss of balance, and nystagmus
What is the 9th cranial nerve and describe its route
glossopharyngeal nerve
originates from the medulla oblongata
exits the skull through the jugular foramen
What do the motor and sensory fibres of the glossopharyngeal nerve innervate
Motor fibres - stylopharyngess muscle (of the pharynx)
Sensory fibres - oropharynx and posterior tongue
What is the function of the glossopharyngeal nerve
swallowing, salivation, gagging; touch, pressure, taste, and pain sensations from tongue, pharynx, and outer ear
What is the clinical test for the glossopharyngeal nerve
gag reflex, swallowing, and coughing
What can be the effects of damage to the glossopharyngeal nerve
difficulty swallowing
What is the 10th cranial nerve and describe its route
the vagus nerve
arises from the medulla oblongata and exits the skull at the jugular foramen
What do the sensory fibres of the vagus nerve innervate
external auditory meatus & tympanic membrane
What do the motor fibres of the vagus nerve innervate
the muscles of the larynx, respiratory passages, lungs, heart, oesophagus, stomach, small intestine, most of the large intestine & the gallbladder.
What are the functions of the vagus nerve
swallowing; taste; speech; respiratory, CV, and GI regulation; sensations of hunger, fullness, and intestinal discomfort
What can be the effects of damage to the vagus nerve
hoarseness or loss of voice; impaired swallowing and GI motility
What is the 11th cranial nerve and describe its route
the accessory nerve
originates from both the medulla oblongata and from the spinal cord.
emerges out through the jugular foramen
What does the accessory (11th) nerve innervate
Trapezius and sternocleidomastoid muscles
What is the function of the accessory nerve
head, neck, and shoulder movements
What are the clinical tests for the accessory nerve
rotate head and shrug shoulders against resistance
What can be the effects of damage to the accessory nerve
impaired movement of head, neck, and shoulders; paralysis of sternocleidomastoid
What is the 12th cranial nerve and describe its route
Hypoglossal
Originates in the medulla oblongata
exits skull through the hypoglossal canal
What does the hypoglossal nerve innervate
the muscles of the tongue
What are the functions of the hypoglossal nerve
tongue movements of speech, food manipulation, and swallowing
What is the clinical test for the hypoglossal nerve
tongue function
What can be the effects of damage to the hypoglossal nerve
difficulty in speech and swallowing; atrophy of tongue; inability to stick out (protrude) tongue
