Intro to CN

Question 1

CN I to XII

Answer 1

• CN I: Olfactory (S)
• CN II: Optic (S)
• CN III: Oculomotor (M)
• CN iV: Trochlear (M)
• CN V: Trigeminal (B)
• CN VI: Abducens (M)
• CN VII: Facial (B)
• CN VIII: Vestibulocochlear (S)
• CN iX: Glossopharyngeal (B)
• CN X: Vagus (B)
• CN XI: Accessory (M)
• CN XII: Hypoglossal (M)

May be Mixed, Sensory only or Motor only

• 4 carry visceral motor/parasympathetic fibres
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Question 2

Spinal nerves

Answer 2

• all Mixed & all carry:
• somatic motor fibres to the body wall
• visceral motor (sympathetic) fibres to body wall
• somatic sensory fibres from the body wall

Question 3

CN V branches

Answer 3

• CN V1: ophthalmic nerve (sensory)
• CN V2: maxillary nerve (both)
• CN V3: mandibular (motor)

Question 4

Visceral motor: Parasympathetic

Answer 4

• CN III: smooth (instrinsic) muscles of the eye
• CN VII: lacrimal gland to submandibular & sublingual salivary gland
• CN IX: to parotid salivary gland
• Parasympathetic ganglia of III, VII, IX are close to, but not in, wall of target organ
• CN X: thoracic viscera & ab viscera up to LCF

Question 5

Visceral sensory

Answer 5

• CN IX: from carotid body & sinus (cardiovascular)
• CN X: from aortic arch (cardiovascular), lower larynx, tracheobronchial tree, esophagus, gut tube to LCF

Question 6

CN X damage

Answer 6

• damage to CN X will paralyse skeletal muscle of soft palate, pharynx and larynx
• CN testing evaluates CN X, not cranial accessory
• an asymmetrical soft palate or asymmetrical vocal cords are both symptomatic of CN X damage

Question 7

Cranial nerve sensory ganglia

Answer 7

• CN V ganglion
• Geniculate ganglion of CN VII
• Superior & Inferior ganglia of CN IX
• Superior & Inferior ganglia of CN X