Cranial Nerves Flashcards
Cranial Nerves (12 pairs)
Motor and sensory innervation of head and neck; carry sympathetic and parasympathetic fibers of ANS
CN 1= Olfactory (bulb and tract) CN 2= Optic CN 3= Oculomotor CN 4= Trochlear CN 5= Trigeminal CN 6= Abducent CN 7= Facial CN 8= Vestibulocochlear CN 9= Glossopharyngeal CN 10= Vagus CN 11= Accessory CN 12= Hypoglossal
Pure Sensory Cranial Nerves (3)
CN 1- olfactory
CN 2-optic
CN 8- vestibulocochlear
Special Sensory Cranial Nerves (6)
info about smell, vision, taste, hearing and balance CN 1- olfactory CN 2- optic CN 7- facial CN 9- glossopharyngeal CN 10- Vagus CN 8- Vestibulocochlear
Somatic Sensory Cranial Nerves (4)
info about body position, pain, temperature, vibration, and touch CN 5- Trigeminal CN 7- Facial CN 9- Glossopharyngeal CN 10- Vagus
Visceral Sensory (2) Cranial Nerves
sensory info except pain from viscera (organs)
CN 9- glossopharyngeal
CN 10- vagus
Visceral Motor (4) Cranial Nerves
autonomic innervation of cardiac and smooth m. as well as glands CN 3- Oculomotor CN 7- Facial CN 9- Glossopharyngeal CN 10- Vagus
Branchial Motor (5) Cranial Nerves
innervation of muscles derived from branchial arches CN 5- Trigeminal CN 7- Facial CN 9- Glossopharyngeal CN 10- Vagus CN 11- Accessory
Somatic Motor (4) Cranial Nerves
innervation of muscles derived from myotomes CN 3- Oculomotor CN 4- Trochlear CN 6- Abducent CN 12- Hypoglossal
Purely Motor Cranial Nerves (5)
CN 3- oculomotor CN 4- Trochlear CN 6- Abducent CN 11- Accessory CN 12-Hypoglossal
Mixed Cranial Nerves (4)
both motor and sensory
CN 5- Trigeminal
CN 7- Facial
CN 9- Glossopharyngeal
CN 10- Vagus
GVE (General Visceral Efferent) Cranial Nerves (4)
CN 3- Oculomotor
CN 5- Trigeminal
CN 7- Facial
CN 9- Glossopharyngeal
CN 1
olfactory (bulb and tract)
passes through the ethmoid bone which contains the cribiform plate. The CN 1 will travel through the foramina in the cribiform plate and go to olfactory epithelium
CN 2
optic
passes through the optic canal in the sphenoid bone; neuron cell bodies are in the retina; if eyeball damage/ pituitary gland tumor occurs and damaged CN 2 then visual defects will occur
CN 3
oculomotor
originates from midbrain-pons junction and will travel through cavernous sinus, then pass through superior orbital fissure, then through common tendinous ring (where the eye muscles emerge from)
innervates: levator palpebrae superioris, inferior rectus, medial rectus, and inferior oblique
if damaged: palsy which is characterized by ptosis, eye will be pointed down and out, pupil is fixed and dilated
damage can be caused by injury to cavernous sinus and aneurysms to superior/posterior cerebral arteries
CN 4
trochlear
originates from dorsal midbrain and passes through cavernous sinus–>superior orbital fissure–>common tendinous ring where eye muscles originate.
innervates: superior oblique m.
injury to this nerve causes trochlear nerve palsy which is inability to look down and inward; can be caused by injury to cavernous sinus
CN 5
trigeminal
3 branches:
V1-ophthalmic (sensory)- sensory from skin of forehead, scalp, eyelids, nasal mucous membranes (touch, pressure, temp, vibe, pain); several branches of V1= frontal n, lacrimal n, nasocillary n, supratrochlear n, supraorbital n, off V1; passes through superior orbital fissure; injury due to inflammation can cause anesthesia of area
V2- maxillary (sensory)- sensory of upper lip, cheek, palate, lower eyelid, side of nose and maxillary sinus; passes through foramen rotundum; several branches= greater & lesser palantine n, nerve of pterygoid canal, pterygopalatine ganglion, zygomaticofacial n, zygomaticotemporal n; injury due to inflammation can cause anesthesia and trigeminal neuralgia (intense pain)
V3- mandibular (sensory + motor)- sensory of lower jaw, mucosa of anterior 2/3 of tongue; motor is chewing and swallowing; passes through foramen ovale, injury due to inflammation can cause anesthesia and difficulty chewing; motor portion innervates temporalis, lat and med pterygoids, masseter, tensor veli palatini, tensor tympani, mylohyoid, and digastric anterior
CN 6
Abducent
motor
originates from the abducent nucleus at the pons; nerve will emerge from the junction between the pons and medulla–>cavernous sinus–> superior orbital fissure–> common tendinous ring
Lateral rectus muscle abducts the eye; directs the pupil laterally; if this is damaged by cavernous sinus injury/skull fracture abducent nerve palsy can occur which can cause diplopia (double vision), impaired eye abduction, and tendency for eye to turn medially
CN 7
Facial Nerve
Both motor and sensory
Emerges from junction of pons and medulla–>through internal acoustic meatus–> through stylomastoid foramen–> through substance of parotid gland–>innervate the muscles of fascial expression.
There are 5 main branches: Temporal, Zygomatic, Buccal, Marginal Mandibular and Cervical branches.
carries some general sensation/sensory info from region around the ear. Also carries taste sensation from the anterior 2/3 of the tongue. innervates all glands in head except sweat and parotid.
injury to chorda tympani nerve and parotid gland can injury CN 7
CN 8
Vestibulocochlear; made up of two branches: vestibular and cochlear
hearing and balance
Emerges between the junction of pons and medulla–> internal acoustic meatus
If a patient has injury (such as tumor), they will have hearing impairment/ hearing loss and possibly vertigo (dizziness)
CN 9
Mixed cranial nerve (motor and sensory). Goes through jugular foramen.
Sensory info=posterior 1/3 of tongue, tonsils, soft palate, pharynx, middle ear, auditory tube, and mastoid air cells.
Visceral sensory= chemoreceptors in carotid body to monitor O2 and baroreceptors in carotid sinus to monitor arterial BP
Motor=elevates pharynx in speech and swallowing
Innervates stylopharyngeus muscle
If you have an injury to this nerve (ex: neck laceration), the patient will have a diminished gag reflex, difficulty swallowing (dysphagia), speech difficulty (dysarthria) and loss of taste and somatic sensation from posterior 1/3 tongue.
CN 10
Vagus Nerve
Both sensory and motor
Emerges from the medulla and passes through jugular foramen
Sensory info from pharynx, larynx, external ear, external auditory canal, tympanic membrane, posterior meninges; taste from epiglottis
Abdominal viscera
Chemoreceptors in aortic body and stretch receptors in aortic arch walls
Motor= speech
Innervates: muscles of soft palate (except stylopharyngeus and tensor veli palatini), pharyngeal constrictor m.’s, salpingopharyngeus, palatopharyngeus, palatoglossus, cricothyroid, larynx m.’s
Injury might cause sagging soft palate, difficult coughing, clearing throat, and swallowing (dysphagia)
CN 11
Accessory Nerve
Purely motor that helps with head and neck movement
Emerges from spinal cord–>up spinal cord–> foramen magnum–>jugular foramen–>innervation sternocleidomastoid and trapezius
Injury (ex: neck laceration) to this nerve will result in difficulties in turning your head to opposite side, shrug your shoulders
Note: no part of CN 11 arises from medulla
CN 12
Hypoglossal
Somatic motor- swallowing, sucking, chewing, tongue protrusion
Emerges from medulla sides–>through hypoglossal canal–> curves forward near angle of mandible to enter tongue
Innervates: intrisic and extrinsic tongue muscles (except palatoglossus)
If injured, protruded tongue deviates toward side of injury Will also have problems chewing because basically paralyzed tongue
Autonomic Nerves in Head
Cillary Ganglion
Pteryopalatine Ganglion
Otic Ganglion
Submandibular Ganglion
