Cranial Nerves Flashcards

Flashcards about Cranial Nerves

List the 12 cranial nerves.

Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal

What are the four cranial nerves that originate from the midbrain?

I, II, III, IV

What are the four cranial nerves that originate from the pons?

V, VI, VII, VIII

What are the four cranial nerves that originate from the medulla?

IX, X, XI, XII

What does GSA stand for?

General Somatic Afferent

What does GSE stand for?

General Somatic Efferent

What does GVA stand for?

General Visceral Afferent

What does GVE stand for?

General Visceral Efferent

What does SSA stand for?

Special Somatic Afferent

What does SVA stand for?

Special Visceral Afferent

What does SVE stand for?

Special Visceral Efferent

What type of nerve is the Olfactory Nerve (CN I) and what sense does it govern?

Sensory (Special Visceral Afferent); Olfaction (Smell)

What are some potential lesions of the Olfactory Nerve (CN I)?

Ethmoid bone fracture leading to Anosmia (Loss of smell) and/or Runny nose from CSF leakage

What type of nerve is the Optic Nerve (CN II) and what sense does it govern?

Sensory (Special Somatic Afferent); Vision

What is a function of the Optic Nerve (CN II)?

Afferent portion of Pupillary Light Reflex

What are some potential lesions of the Optic Nerve (CN II)?

Loss of vision in visual fields with respect to location of the physical lesion, Blurry Vision, Loss of pupillary light reflex

What type of nerve is the Oculomotor Nerve (CN III)?

Motor (General Somatic Efferent & General Visceral Efferent)

What muscles are innervated by the Oculomotor Nerve (CN III)?

Extraocular muscles: superior rectus, medial rectus, inferior rectus, inferior oblique, levator palpebrae superioris. Intraocular muscles: Sphincter pupillae & Ciliary m.

What are some potential lesions of the Oculomotor Nerve (CN III)?

Down and out gaze, Ptosis (droopy eyelid), Loss of pupillary constriction, accommodation and pupillary light reflex and corneal blink reflex.

What type of nerve is the Trochlear Nerve (CN IV)?

Motor (General Somatic Efferent)

What movement does the Trochlear Nerve (CN IV) control, and via what muscle?

Eye movement (Looking down and in) via superior oblique m.

What are some potential lesions of the Trochlear Nerve (CN IV)?

Diplopia (double vision) when looking down and in, slight head tilt away from side of lesion, prone to head injuries.

What type of nerve is the Abducens Nerve (CN VI)?

Motor (General Somatic Efferent)

What movement does the Abducens Nerve (CN VI) control, and via what muscle?

Eye movement (provides lateral rectus m. innervation); Abduction

What are some potential lesions of the Abducens Nerve (CN VI)?

Inability to abduct eyeball and possible diplopia; commonly caused by cavernous sinus thrombosis due to proximity to ICA.

What type of nerve is the Trigeminal Nerve (CN V)?

Motor & Sensory (Special Visceral Efferent & General Somatic Afferent)

What is a function of the Trigeminal Nerve (CN V)?

Afferent limb (V1) of the corneal blink reflex

What type of nerve is the Facial Nerve (CN VII)?

Motor & Sensory (Special Visceral Efferent, General Visceral Efferent, Special Visceral Afferent, General Visceral Afferent, General Somatic Afferent)

What are the main functions of the Facial Nerve (CN VII)?

Facial movement NOT facial sensation, Taste from anterior 2/3 of the tongue, Parasympathetic innervation to lacrimal, submandibular, and sublingual glands, Efferent limb of corneal blink reflex

What are some potential lesions of the Facial Nerve (CN VII)?

Facial muscle weakness ipsilaterally, Dry eyes, dry mouth, Impairment of taste from ant. 2/3 of tongue

What type of nerve is the Vestibulocochlear Nerve (CN VIII)?

Pure Sensory (Special Somatic Afferent)

What are the two components of the Vestibulocochlear Nerve (CN VIII) and what do they innervate?

Vestibular n. innervates vestibules responsible for balance; Cochlear n. innervates cochleae responsible for hearing

What are some potential lesions of the Vestibulocochlear Nerve (CN VIII)?

Hearing loss (partial or complete), Tinnitus, Vertigo and nystagmus; Possibly due to fracture of internal acoustic meatus

What type of nerve is the Glossopharyngeal Nerve (CN IX)?

Motor (Special Visceral Efferent), Sensory (General Visceral Afferent, Special Visceral Afferent, General Somatic Afferent), Parasympathetic (General Visceral Efferent)

What are the main functions of the Glossopharyngeal Nerve (CN IX)?

Elevation of pharynx (stylopharyngeus m.), Innervates the pharynx, Taste from post. 1/3 of tongue, Innervates external acoustic meatus, Innervates the carotid sinus and body, Secretion of saliva (parotid gland), Afferent limb of the gag reflex, Afferent limb of the carotid sinus reflex

What are some potential lesions of the Glossopharyngeal Nerve (CN IX)?

Loss of gag reflex, Loss of carotid sinus reflex, Loss of taste from post. 1/3 of tongue, Dry mouth (Xerostomia), Difficulty swallowing (Dysphagia)

What type of nerve is the Vagus Nerve (CN X)?

Sensory (General Somatic Afferent, Special Visceral Afferent, General Visceral Afferent), Motor (Special Visceral Efferent), Parasympathetic (General Visceral Efferent)

What are some potential lesions of the Vagus Nerve (CN X)?

Dysphonia/aphonia (vocal cord paralysis), Difficulty or impaired swallowing, Loss of gag reflex, Uvula deviation away from lesion (impaired palate elevation), Loss of cough reflex

What type of nerve is the Accessory Nerve (CN XI)?

Motor (General Somatic Efferent)

What are some potential lesions of the Accessory Nerve (CN XI)?

Usually due to trauma (sternoclavicular joint dislocation), Ipsilateral shoulder droop and pain, Inability to raise shoulders and arms overhead, Difficulty rotating head to contralateral side of lesion

What type of nerve is the Hypoglossal Nerve (CN XII)?

Motor (General Somatic Efferent)

What are some potential lesions of the Hypoglossal Nerve (CN XII)?

Dysarthria and difficulty swallowing, Deviation of tongue towards the injured side when protruded ("Lick your wounds")

Summarize the affiliation of nerves to sensory, motor, or both

S = Pure Sensory; M = Pure Motor; B = Both

List the Cranial Nerves carrying parasympathetic fibers

CN 3, 7, 9, 10

What is the mnemonic device to recall the cranial nerves and their function?

Oh Oh Oh To Touch And Feel Very Good Velvet Ah Heaven! Some Say Marry Money But My Brother Says Big Brain Matters More

What are the afferent and efferent limbs of the Pupillary Light Reflex?

Afferent limb: CN II; Efferent limb: CN III

What are the afferent and efferent limbs of the Corneal (blink) Reflex?

Afferent limb: CN V1 (Nasociliary branch); Efferent limb: CN VII

What are the afferent and efferent limbs of the Sneeze Reflex?

Afferent limb: CN V2; Efferent limb: CN X

What are the afferent and efferent limbs of the Jaw Jerk Reflex?

Afferent limb: CN V3; Efferent limb: CN V3

What are the afferent and efferent limbs of the Gag Reflex?

Afferent limb: CN IX; Efferent limb: CN X

What are the afferent and efferent limbs of the Cough Reflex?

Afferent limb: CN X; Efferent limb: CN X