Flashcards
CN Clinical Perspective
Cards in this deck (16)
- 1If an animal lacks a menace response,what does it imply?Optic nerve is damaged = no SSA signal; Facial nerve damaged = failed motor to orbicularis oculi m. via palpebral branch of the auriculotemporal n. (VII)
- 2What would be the consequences of a tumor in the occulomotor nerve nucleus?Ptosis: upper eyelid cannot be raised due to paralysis of levator palpebrae superioris m.
Lateral strabismus: undamaged lateral rectus m. and retractor bulbi m. contraction deviates eyeball to the lateral side (eye m. innervated by CN III non-functional - 3What does the lack of blink response at the medial canthus suggest?Suggests injury to the ophthalmic n. (V); specifically the frontal n. and infratrochlear n. of the nasociliary branch
- 4Describe the cause of Horner's Syndrome and name its clinical signs.Injury to sympathetic division of the autonomic nerves that innervate the eye
Signs: ptosis, constricted pupil of the eye (miosis), sunken eye (enophthalmos), conjunctival hyperemia and prolapse of the nictitating membrane - 5What part of the cat is abnormal? Which cranial nerves are close to this structure?Tympanic bulla
May require a tympanic bulla osteotomy
The glossopharyngeal, vagus, accessory, and hypoglossal nerve all exit the skull through the tympano-occipital fissure (hypoglossal canal opens into fissure) - 6What is the cause of medial strabismus?Damage to the abducens n. (CN VI) causes inability to retract eyeball due to non-functional lacteral rectus and retractor bulbi
- 7What response is elicited by the upper lip pinch test? Which muscle is being pinched and what cranial nerve innervates it?Initiates snarling response; pinching orbicularis oris m. to activate muscles of facial expression innervated by the facial nerve
- 8If the nostrils (interior) are tickled with a feather tip or cotton bud elicits no reaction, which cranial nerve branch is most likely affected?Caudal nasal branch of the maxillary n. (V) Caudal nasal nerve runs through sphenopalatine foramen to innervate nasal mucosa and ventral nasal meatus
- 9What makes up the pharyngeal plexus?The pharyngeal branches from the distal and proximal vagal ganglia (CN X), pharyngeal branch of the glossopharyngeal n. (CN IX), branches from the hypoglossal n., and postganglionic sympathetic axons from the cranial cervical ganglion
- 10Which types of fibers from the pharyngeal plexus mediate the gag reflex? How is it mediated?GSA (pharyngeal mucosa) and GSE (pharyngeal m.)
When a bitter substance is in the caudal 1/3rd of the tongue/laryngopharynx, the hyopharyngeus, thyropharyngeus, and cricopharyngeus contract simultaneously to prevent entry into the esophagus. The hyoglossus, genioglossus and geniohyoideus m. pull the tongue rostrally to spit out - 11Describe the sensory input for cough reflexSVA and pharyngeal GVA of the cranial laryngeal n. (CN X) signal to close the aditus laryngis when food or water reaches the oropharynx; accidental entry irritates laryngeal mucosa via GVA
- 12Describe the motor response of the cough reflexCranial laryngeal n. contracts cricothyroideus and caudal laryngal n. contracts the cricoarytenoideus dorsalis and all other muscles of the larynx to produce the cough
- 13If a dog is vestibular, which cranial nerve may be involved? How is this cranial n. being affected?Vestibulocochlear n.
Inflammation from an inner ear infection may be affecting the nerve's ability to transmit impulses relating to the position of the head relative to gravity and to linear and angular acceleration. - 14Why can the vestibular n. and the cochelar n. be affected independently? What parts of the ear do they innervate?Vestibular and cochlear nerve have two separate ganglia and two separate nuclei of origin. The vestibular n. innervates the hair cells in cristae ampullare and macula utericuli and sacculi of membranous labyrinth. The cochlear n. innervate hair cells of the spiral organ in the cochlear duct
- 15What possible effects could result from damage to the mandibular n. (V)?Atrophy of masticatory muscles, temporal fossa, zygomatic arch. If bilateral, will caused dropped lower jaw.
- 16If a patient presents with dorsolateraral strabismus and abnormal position ov vessels in the fundus, what cranial n. could be affected?Trochlear n. (CN IV); dorsal oblique m. non-functional
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- Anatomy (Cranial Nerves ) Flashcards on CN Clinical Perspective, created by Megan Cobarruvias on 16/11/2017.
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- Megan Cobarruvias
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