Cranial Nerves Flashcards
What are the 12 cranial nerves?
I - Olfactory II - Optic III - Oculomotor IV - Trochlear V - Trigeminal VI - Abducens VII - Facial VIII - Vestibulocochlear IX - Glossopharyngeal X - Vagus XI - Accessory XII - Hypoglossal
What are the divisions of CN V?
V1 - Opthalmic division of trigeminal
V2 - Maxillary division of trigeminal
V3 - Mandibular division of trigeminal
What foramen does CN I pass through?
Cribiriform plate
What foramen does CN II pass through?
Optic canal
What foramen do CNs III, IV, V1, and VI pass through?
Superior orbital fissure
What foramen does CN V2 pass through?
Foramen rotundum
What foramen does CN V3 pass through?
Foramen ovale
What foramen do CNs VII and VIII pass through?
Internal acoustic meatus
What foramen do CNs IX, X, and XI pass through?
Jugular foramen
What foramen does CN XII pass through?
Hypoglossal canal
What CNs are part of the somatic motor modality?
III, IV, VI, and XII
What CNs are part of the branchial motor modality?
V, VII, IX, X, and XI
What CNs are part of the visceral motor (parasympathetic) modality?
III, VII, IX, and X
What CNs are part of the visceral sensory modality?
IX and X
What CNs are part of the general sensory modality?
V, VII, IX, and X
What CNs are part of the special sensory modality?
I, II, VII, VIII, and IX
What nuclei are part of the somatic motor modality?
Oculomotor, trochlear, abducens, and hypoglossal
What nuclei are part of the branchial motor modality?
Masticator, facial, ambiguous, and accessory
What nuclei is part of the visceral motor (parasympathetic) modality?
Edinger-Westphal, superior salivatory, inferior salivatory, and dorsal vagus
What nucleus is part of the visceral sensory modality?
Solitarius
What nucleus is part of the general sensory modality?
Trigeminal
What nuclei are part of the special sensory modality?
Mitral cells of olfactory bulb, ganglion cells of retina, gustatory, vestibular, and cochlear
What does CN III innervate?
All extraocular eye muscles except superior, oblique, and lateral rectus; ciliary muscle and constrictor pupillae
What does CN IV innervate?
Superior oblique
What does CN VI innervate?
Lateral rectus
What does CN XII innervate?
Intrinsic and extrinsic tongue muscles except palatoglossus
What What does CN V innervate?
Muscles of mastication
What does CN VII innervate?
Muscles of facial expression, all glands of the head except integumentary and parotid, and taste
What does CN IX innervate?
Muscles of pharynx and larynx, parotid gland, visceral afferent information necessary for visceral reflexes, nausea, but not pain in viscera; also taste
What does CN X innervate?
Muscles of pharynx and larynx, all thoracic viscera and abdominal viscera to the splenic flexure, and visceral afferent information necessary for visceral reflexes, nausea, but not pain in viscera
What does CN XI innervate?
Trapezius and sternocleidomastoid
What does CN I function in?
Smell
What does CN II function in?
Vision
What does CN VII and IX function in?
Taste
What does CN VIII function in?
Balance and hearing
What nerve is derived from the 1st (mandibular) pharyngeal arch?
CN V
What nerve is derived from the 2nd (hyoid) pharyngeal arch?
CN VII
What nerve is derived from the 3rd pharyngeal arch?
CN IX
What nerves are derived from the 4th and 6th pharyngeal arches?
CN X; superior laryngeal branch and recurrent laryngeal branch
What muscles are derived from the 1st (mandibular) pharyngeal arch?
Muscles of mastication, mylohyoid, anterior belly of digastric, tensor tympanic, and tensor veli palatine
What muscles are derived from the 2nd (hyoid) pharyngeal arch?
Muscles of facial expression, stapedius, stylohyoid, posterior belly of digastric
What muscles are derived from the 3rd pharyngeal arch?
Stylopharyngeus
What muscles are derived from the 4th and 6th pharyngeal arches?
Cricothyroid, levator veli palatini, constrictors of pharynx, intrinsic muscles of larynx, and striated muscles of esophagus
What skeletal structures are derived from the 1st (mandibular) pharyngeal arch?
Malleus and incus
What skeletal structures are derived from the 2nd (hyoid) pharyngeal arch?
Stapes, styloid process, lesser Cornu of hyoid, and upper part of body of hyoid bone
What skeletal structures are derived from the 3rd pharyngeal arch?
Greater cornu of hyoid and lower part of body of hyoid bone
What skeletal structures are derived from the 4th and 6th pharyngeal arches?
Thyroid cartilage, cricoid cartilage, arytenoid cartilage, corniculate cartilage, and cuneiform cartilage
What ligaments are derived from the 1st (mandibular) pharyngeal arch?
Anterior ligament of malleus and sphenomandibular ligament
What ligament is derived from the 2nd (hyoid) pharyngeal arch?
Stylohyoid ligament
Which CNs carry preganglionic parasympathetic fibers?
III, VII, IX, and X
What condition is caused by damage to CN I?
Anosmia (partial or total loss of smell)
What condition is caused by damage to CN II?
Anopsia (visual defects)
What condition is caused by damage to CN III?
Ptosis (upper eyelid droop), paralysis of eye muscles, leading to strabismus (eyes not in parallel/deviated improperly), diplopia (double vision), and focusing difficulty
What conditions are caused by damage to CN IV?
Paralysis of superior oblique, leading to strabismus (eyes not in parallel/deviated improperly), diplopia (double vision)
What conditions are caused by damage to CN VI?
Paralysis of lateral rectus limits lateral movement of the eye; diplopia (double vision)
A patient presents with their right eye downward and outward gazing, a dilated pupil, and ptosis. What is this called and what nerve is damaged?
Right oculomotor nerve palsy (CN III)
A patient presents to the clinic for an eye exam. When you ask the patient to look to their left, their right eye looks normal, but their left eye does not abduct. What is this called and what nerve is damaged?
Left abducent nerve palsy (CN VI)
A patient presents with intense, pulsating pain in the face that lasts between several minutes to a few hours. What is this called and what nerve is damaged?
Trigeminal neuralgia, which is caused by inflammation of the sensory components of the trigeminal nerve
What conditions are caused by damage to CN VII?
Decreased tearing (dry eye) and decreased salivation (dry mouth)
A patient presents C/O loss of sensation to anterior 2/3s of their tongue. You notice some paralyzed facial muscles, droopy eyelids, and sagging at the corner of the mouth. What is this called and what nerve is damaged?
Facial nerve palsy (Bell palsy) (CN VII)
A patient with loss of balance, nausea, vomiting, and dizziness could be caused by damaged to what nerve?
Lesions of vestibular branch of CN VIII
A patient presenting with deafness or a loss of hearing could be caused by damage to what nerve?
Lesions to cochlear branch of CN VIII
What conditions are caused by damage to CN IX?
Reduced salivary secretion (dry mouth), loss of taste sensations to posterior 1/3 of tongue
What conditions are caused by damage to CN X?
Hoarseness, monotone or complete loss of voice as a result of paralysis of this nerve; lesions can cause difficulty in swallowing or impaired gastrointestinal system mobility
What conditions are caused by damage to CN XI?
Paralysis of trapezius and sternocleidomastoid, resulting in difficulty in elevating shoulder or turning the head to the opposite side
What conditions are caused by damage to CN XII?
Swallowing and speech difficulties due to impaired tongue movement
If a patient presents with a protruded tongue deviating to the left side, what nerve is damaged?
Left CN XII lesion
Which CNs have parasympathetic (autonomic) function?
III, VII, IX, and X
What is the parasympathetic motor function of CN III?
Constricts pupil and contracts ciliary muscles to make lens of the eye more puffy for near vision
What is the parasympathetic motor function of CN VII?
Increases secretion of lacrimal gland of the eye, submandibular gland, and sublingual salivary gland
What is the parasympathetic motor function of CN IX?
Increases secretion of parotid salivary gland
What is the parasympathetic motor function of CN X?
Innervates smooth muscle and glands of heart, lungs, larynx, trachea, and most abdominal organs
What general motions of the eye is the oculomotor responsible for?
Movement up and/or in
What general motions of the eye is the trochlear nerve responsible for?
Downward
What general motions of the eye is the abducens nerve responsible for?
Outward
What are the major branches off CN V1?
Lacrimal, frontal, nasociliary, and meningeal branch
What are the major branches off CN V2?
Zygomatic, infraorbital, superior alveolar, palatine, and meningeal
What are the major branches off CN V3?
Buccal, lingual, inferior alveolar, auriculotemporal, meningeal, medial/lateral pterygoid, masseteric, deep temporal, and mylohyoid