Oro-Maxillofacial Surgery MCQ Answer 2

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The Correct Answer is D

CRANIAL NERVES: SUMMARY TABLE

Cranial nerve	Nucleus name	Nucleus location	Function	Symptom/sign of damage
Olfactory (CNI)	Anterior olfactory	Olfactory tract	Smell	Anosmia
Optic (CNII)	Lateral geniculate nucleus	Thalamus	Vision	Blindness
Oculomotor (CNIII)	Oculomotor Edinger Westphal	Midbrain Midbrain	Eye movement (elevation, adduction)	Eye deviates down & out Loss of pupillary/accommodation reflexes
Trochlear (CNIV)	Trochlear	Midbrain	Eye movement (depression of adducted eye)	Diplopia, lateral deviation of eye
Trigeminal (CNV)	Principal Spinal Mesencephalic Motor	Pons Medulla Pons/midbrain Pons	Facial sensation Mastication	Facial aneasthesia Loss of pain sensation Insignificant Weakness/loss of mastication
Abducent (CNVI)	Abducent	Pons	Eye movement (Abduction)	Medial eye deviation
Facial (CNVII)	Motor Solitary Superior salivatory	Pons Pons Pons	Facial expresssion Taste Salivation, lacrimation	Paralysis of facial nerve muscles (+ hyperacuisis) Loss of taste (anterior 2/3rds of tongue) Dry mouth, loss of lacrimation
Vestibulocochlear (CN VIII)	Vestibular Cochlear	Medulla Medulla	Balance Hearing	Vertigo, dysequilibrium, nystagmus Hearing
Glossopharyngeal (CN IX)	Nucleus ambiguus Inferior salivatory Solitary	Medulla Medulla Medulla	Taste Salivation Innervation of pharynx	Loss of taste (posterior 1/3rd of tongue) Insignificant Loss of gag reflex
Vagus (X)	Nucleus ambiguus Dorsal motor vagal Solitary	Medulla Medulla Medulla	Swallowing & talking Cardiac, GI tract, respiration Taste	Dysphagia & hoarseness of voice Insignificant Loss of cough reflex (larynx/pharynx), loss of taste (hard palate)
Cranial Accessory (XI) Spinal accessory	Nucleus ambiguus Spinal accessory	Medulla Cervical cord	Pharynx/larynx muscles Neck & shoulder movement	Insignificant Head turning/shoulder shrugging weakness
Hypoglossal (XII)	Hypoglossal	Medulla	Tongue movement	Atrophy of tongue muscles, deviation on protrusion, fasciculaations

Nerve	Main Function(s)	Cranial exit point	Peripheral innervation of head
Olfactory (CNI)	Smell	Cribiform plate	Mucosa of nasal cavity
Optic (CNII)	Vision	Optic foramen	Retina of eye
Oculomotor (CNIII)	Eye movement (elevation, adduction)	Superior orbital fissure	All extraocular eye muscles except SO & LR
Trochlear (CNIV)	Eye movement (depression of adducted eye)	Superior orbital fissure	Superior oblique (extraocular eye muscle)
Trigeminal (CNV)	Facial sensation Mastication	V1 - Superior orbital fissure V2 foramen rotundum V3 — foramen ovale	Cutaneous sensation of nose, eyes and scalp. Cutaneous sensation of face: maxilla, nasal mucosa, upper lip and teeth Cutaneous sensation of lower face: mouth mucosa, lower jaw teeth, tmj and anterior 2/3rd of tongue. Motor supply to muscles of mastication
Abducent (CNVI)	Eye movement (Abduction)	Superior orbital fissure	Lateral rectus (extraocular eye muscle)
Facial (CNVII)	Facial expresssion Taste	Entry: Internal acoustic meatus Exit: stylomastoid foramen	Motor: muscles of facial expression and scalp. Sensory; taste from anterior 2/3rd of tongue
Vestibulocochlear (CN VIII)	Balance Hearing	Internal acoustic meatus	Inner ear labyrinth structures (semi circular canal and cochlear apparatus)
Glossopharyngeal (CN IX)	Taste Salivation Innervation of pharynx	Jugular foramen	Posterior 1/3rd of tongue Parotid gland Mucosa and elevator muscles of pharynx.
Vagus (X)	Swallowing & talking Taste	Jugular foramen	Palatal muscles, pharyngeal constrictors, vocal cords Taste & sensation to epiglottis
Cranial Accessory (XI) Spinal accessory	Swallowing & talking Neck & shoulder movement	Jugular foramen	Motor supply to larynx and Pharynx Head rotation & shoulder shrugging
Hypoglossal (XII)	Tongue movement	Hypoglossal canal	Intrinsic & some extrinsic tongue muscles