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Tom Eck – ecktw@umdnj.edu. HAD UNIT II CALM REVIEW. Cranial nerves are tested directly or indirectly on the majority of questions Know the course of each nerve, especially the foramen each passes through Know cutaneous distribution for sensory nerves and muscles innervated for motor nerves
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Tom Eck – ecktw@umdnj.edu HAD UNIT II CALM REVIEW
Cranial nerves are tested directly or indirectly on the majority of questions Know the course of each nerve, especially the foramen each passes through Know cutaneous distribution for sensory nerves and muscles innervated for motor nerves Memorize presentation of deficits associated with loss of each nerve Major Points
Cranial Nerves: Sensory Cranial Nerves: Motor Cranial Nerves: Autonomic Vasculature Neck Lymphatics Embryology Connections Major topics
CN I – Olfactory – Olfaction CN II – Optic – Vision CN V – Trigeminal – Facial Sensation CN VII – Facial – Taste CN VIII – Vestibulocochlear – Balance, Hearing CN IX – Glossopharyngeal – Pharyngeal Sensation CN X – Vagus – Laryngeal Sensation CRANIAL NERVES: SENSORY
Cranial Foramina , Ophthalmic artery Middle meningeal artery , Labyrinthine artery , Posterior meningeal artery
1. which bone, when fractured, may be associated with inability to smell (Anosmia) as well as leakage of CSF? • Nasal • Ethmoid • Vomer • Sphenoid • Lacrimal 10
Ethmoidal fracture • May result in damage to CN I fibers as they pass through the cribriform plate of the ethmoid • Ethmoid is particularly vulnerable to trauma • Also associated with CSF leakage (CSF rhinorrhea)
Don’t Do this! Nasogastric Tube
2. Where might tumor invasion lead to anesthesia over the upper lip, infraorbital region, and temporal region? • 1 • 2 • 3 • 4 • 5 10
Maxillary Nerve Injury (V2) • Numbness in the upper lip, infraorbital region, and temporal region suggests the tumor has invaded the maxillary nerve (V2), which exits the skull via the foramen rotundum. • It becomes the infraorbital nerve as it exits the skull via the infraorbital foramen • You would also expect loss of sensation in the nasal mucosa and oral cavity
3. Which of the following Nerves does not contribute to the cutaneousinnervation of the ear? • Maxillary nerve (V2) • Mandibular nerve (V3) • Facial nerve (CN VII) • Glossopharyngeal nerve (CN IX) • Vagus nerve (CN X) 10
Cutaneous Innervation of Ear • Auriculotemporal nerve (CN V3) • Root, superior helix, crus, tragus, ext auditory canal, tympanic membrane • Auricular branch (CN VII) • Concha, ext auditory canal • Jacobsen’s nerve (CN IX) • Concha, ext auditory canal • Arnold’s nerve (CN X) • Concha, ext auditory canal, antihelix • Lesser occipital nerve (C2) • Superoposterior ear • Great auricular (C2,3) • Lateral helix, lobule, posteroinferior ear
4. What nerve has been compromised if a patient experiences numbness of the anterior tongue? • Chorda tympani • Lingual • Hypoglossal • Glossopharyngeal • Vagus 10
Tongue Innervation • Lingual nerve = sensation to anterior 2/3 of tongue • Chorda tympani = taste to anterior 2/3 of tongue • Hypoglossal = motor to intrinsic and extrinsic tongue muscles (except palatoglossus) • Glossopharyngeal = taste AND sensation to posterior 1/3 of tongue • Vagus = taste for small patch near epiglottis
5. Which of the following nerves carries the afferent limb of the corneal reflex? • Ophthalmic • Maxillary • Facial • Occulomotor • Mandibular 0
Corneal Reflex • Afferent Limb: Ophthalmic Nerve, V1 (Nasociliary Branch) • Efferent Limb: Zygomatic Branch of Facial Nerve (CN VII) to palpebral portion of orbicularisoculi • Remember: V1 includes the eyes and the tip of the nose
6. Which nerve supplies the skin overlying the vertex of the skull? • Lacrimal • Supratrochlear • Infratrochlear • Infraorbital • Supraorbital 0
Supraorbital nerve • Supplies much of the forehead and scalp • a branch of the ophthalmic nerve (V1 frontal nerve supraorbital) • Exits the skull via the supraorbital foramen
7. Which area of the face would be expected to experience anesthesia following a fracture of the body of the mandible? • Angle of jaw • Lower lip • Upper lip • Buccal region • Zygomatic region 10
Mental Nerve • branches off the inferior alveolar nerve (V3), which courses through the mandible, supplying the skin of the chin (mental region) and lower lip • exits the mandible via the mental foramen
CN III – Oculomotor CN IV – Trochlearextraocular muscles CN VI – Abducens CN V3 – Mandibular – muscles of mastication CN VII – Facial – muscles of expression CN IX – Glossopharyngeal – stylopharyngeus CN X – Vagus – muscles of pharynx and larynx CN XI – Spinal Accessory – trapezius, SCM CN XII – Hypoglossal – tongue muscles CRANIAL NERVES: MOTOR
8. A posterior fossa tumor impinges on the jugular foramen. Which of the following will be entirely preserved? • swallowing • phonation • chewing • shrugging • taste 10
Jugular foramen: glossopharyngeal (CN IX), vagus (X), spinal accessory (CN XI) Swallowing = vagus, glossopharyngeal, etc. Phonation = vagus (laryngeal muscles) Taste = vagus, glossopharyngeal, (and facial) Shrugging = spinal accessory, etc. Chewing = mandibular nerve (V3) Jugular foramen syndrome
9. Which of the following most directly opposes the action of the temporalis? • Masseter • Infrahyoid muscles • Lateral pterygoid • Medial pterygoid 10
Muscles of Mastication (V3) • temporalis = elevate and retract the mandible • lateral pterygoid = depress and protrude mandible • Elevation:Temporalis, Masseter, Medial Pterygoid • Depression: Lateral Pterygoid, Suprahyoid/Infrahyoid Muscles • Protrusion:Lateral Pterygoid, Masseter, Medial Pterygoid • Retrusion:Temporalis, Masseter • Lateral Movements:Temporalis of same side, Pterygoids of Opposite Side, Masseter • Remember: Unilateral V3 lesion causes deviation to same side as lesion due to unopposed action of the contralateral medial and lateral pterygoid Temporalis Lateral Pterygoid
10. Patients with paralysis of the trigeminal nerve Lose function in which of the following muscles? • Levator veli palatini • Palatopharyngeus • Stylohyoid • Stylopharyngeus • Tensor veli palatini 10
CN V3 - Mandibular nerve (motor) • Temporalis • Masseter • Lateral pterygoid • Medial pterygoid • Mylohyoid • Anterior belly of digastric • Tensor tympani • Tensor velipalatini
11. Which of the following dominates the efferent Limb of the gag reflex? • CN V • CN IX • CN X • CN XII 10
Gag reflex • The nerve supply to the pharynx is derived from the pharyngeal plexus • Glossopharyngeal = sensory supply (afferent limb) • Vagus = motor supply (efferent limb) • Sensory Exceptions: upper nasopharynx supplied by V2 (along with nasal mucosa); lower laryngopharynx supplied by internal laryngeal (CN X) • Motor Exceptions: stylopharyngeus (CN IX), tensor velipalatini (CN V3) *These are also involved in the reflex
12. Which nerve is damaged if a person must constantly press their cheek in while eating? • CN V • CN VII • CN IX • CN X • CN XII 10
Buccinator • innervated by the Facial Nerve • keeps food out of the oral vestibule • meets the superior pharyngeal constrictor (CN X) posteriorly at the pterygomandibularraphe
13. Which of the following would remain functional following compression of the common tendinous ring? • Superior rectus • Lateral rectus • Superior Oblique • Sphincter pupillae • Dilator pupillae 10
Common tendinous ring • Through the common tendinous ring • OPTIC NERVE • Ophthalmic artery • Motor (Occulomotor n. , Abducens n.), except the Trochlear nerve • Nasociliary nerve • Outside: • Opthalmic vein • Sensory (Lacrimal n., Frontal n.), except the nasociliary nerve (which supplies the eyeball) • Trochlear nerve
14. When a patient sticks out her tongue, it deviates to the right side. Which nerve has been damaged? • Left glossopharyngeal • Right glossopharyngeal • Left hypoglossal • Right hypoglossal 10
Hypoglossal nerve • Unilateral lesion causes the tongue to deviate to the SAME side when protruded • The intact genioglossus pulls the back of the tongue forward, deviating the tongue to the other side
COPS 3977 (Parasympathetic Ganglia) Ciliary = CN 3 (pupillary constriction and accomodation) Otic = CN 9 (salivation) Pterygopalatine = CN 7 (lacrimation) Submandibular = CN 7 (salivation) Sympathetic fibers carried by arteries from superior cervical ganglion CRANIAL NERVES: AUTONOMICS
15. A patient complains of dry eyes following trauma. Which of the following nerves may have been damaged at its origin? • Ophthalmic • Oculomotor • Long Ciliary • Facial • Maxillary 10
16. Which ganglion is located just below the foramen ovale and, when damaged, leads to Dry mouth (xerostomia)? • Ciliary • Pterygopalatine • Otic • Submandibular • Geniculate • Trigeminal (semilunar) 10
17. Which of the following nerves carries presynaptic parasympathetic fibers to the submandibular gland? • Greater palatine • Lesser petrosal • Greater petrosal • Chorda tympani • Inferior alveolar 10
SUBMANDIBULAR GANGLION
CILIARY GANGLION Oculomotor Nerve (Pre) Ciliary Ganglion Short Ciliary Nerves (Post)
External Carotid and its branches • Anterior: superior thyroid, lingual, facial • Posterior: Occipital, Posterior Auricular • Medial: Ascending Pharyngeal • Terminal: Superfical Temporal, Maxillary • Internal Carotid and Circle of Willis • Dural Venous Sinuses • Basic Venous Drainage • Be familiar with major branches of maxillary, facial arteries Vasculature
18. When significant trauma is inflicted at the pterion, an epidural hematoma often results. By what route does the involved artery enter the cranium? • Foramen ovale • Foramen rotundum • Foramen spinosum • Foramen lacerum • Sphenopalatine foramen 10
Middle Meningeal artery • pterion = major weak point in skull; location where the frontal, sphenoid, temporal, and parietal bones meet • fracture here associated with laceration of underlying middle meningeal artery (responsible for 70-80% of epidural hematomas) • enters the skull via the foramen spinosum
19. Which Of the following does Not typically branch from the internal carotid artery? • Anterior cerebral artery • Middle cerebral artery • Posterior cerebral artery • Posterior communicating artery • Ophthalmic artery 10
Circle of willis • Represents a major site of anastomosis between the two vertebral arteries (via the basilar artery) and the two internal carotid arteries, which together supply the brain