Cranial Nerves 101 The Nerves are Fun

On Old Olympus’ Towering Tops... Say the names of the cranial nerves backwards in less than 60 seconds. No,no,no. Not yrotcaflo, citpo, rotomoluco... Say them starting with the hypoglossal?

Describe the brainstem exit, cranial exit and general functions of cranial nerves

Where are the olfactory receptors? What is the difference, if any between the olfactory nerve and the olfactory tract?

Olfactory Nerve (SVA), Bulb and Tract Olfactory Epithelium Nerve and Cribiform Plate Olfactory Bulb Olfactory Tract to Piriform Cortex and Amygdala

Optic System 101 Retina Optic Nerve (SSA), Chiasm, Tract Thalamus (Lateral Geniculate Nucleus) and Visual Cortex Superior Colliculus

3,4 and 6 Oculomotor (GSE and GVE) –The Main Mover –Parasympathetic Too Trochlear (GSE) –In and Down (If in, then down) –Two odd things –Trochlea of the Skull Abducens (GSE) –All in a name

Eyeball Kinesiology Adduction -- Abduction Elevation -- Depression Torsion, Rotation(Medial and Lateral)

Torsional Movements

LR 6 SO 4 Lateral Rectus 6 –Abducts Superior Oblique 4 –Depresses and adducts All Others 3 –Superior and Inferior Rectus and Inferior Oblique –“All” except abduction

Oculomotor Parasympathetic Parasympathetic –Pre- and Postganglionic Fibers –Ciliary Ganglia (Motor) Pupillary Reflex –2+3=Constriction –Consensual Response Accomodation Reflex

Describe the brainstem exit, cranial exit and general functions of cranial nerves 7-12.

In addition to moving the face, what else does the facial nerve do? Where would a lesion have to be to involve all of the functions of the facial nerve?

The Full Facial SVE –Muscles of Facial Expression SVA –Taste Anterior 2/3 Tongue –Geniculate Ganglia (Sensory) and Solitary Nucleus GVE=Parasympathetic –Superior Salivatory Nuc –Sphenopalatine Ganglia Lacrimal Gland –Submandibular Ganglia Lingual and Submandibular Glands GSA?

Describe the Anatomy of the Motor Part of the Facial Nerve. Describe the effects of an LMN lesion and an UMN lesion that affects this nerve.

Upper and Lower Face Muscles LMN Damage –Upper and Lower Ipsilateral Face Paralysis UMN Damage –Only Lower Contralateral Face Paralysis

The Labyrinth - Vestibule, Semicircular Canals, and Cochlea Vestibule Semicircular Canals Cochlea

Primary Afferent Fibers Hair Cell Receptors Cochlear Duct –Spiral Ganglia –Cochlear Nuclei –Damage = Ipsilateral Deafness Ampulla and Utricle (and Saccule) –Scarpa’s Ganglia –Vestibular Nuclei –Damage = Ipsilateral Imbalance Hair Cells Nucleus Ganglia

Vagus Nerve Exit –Post Olivary Sulcus –Jugular Foramen Functional Components –Lower Motor Neuron _____________ –Parasympathetic _____________ –Visceral Sensory _____________ –Taste _____________ –Touch and Pain _____________ Speech and Swallowing Thorax and Abdomen ANS Reflexes and Larynx Sensation Uvula and Epiglottis External Auditory Meatus

Glossopharyngeal Nerve Exit –Post Olivary Sulcus –Jugular Foramen Functional Components –Lower Motor Neuron _____________ –Parasympathetic _____________ –Visceral Sensory _____________ –Taste _____________ –Touch and Pain _____________ “Swallowing” Salivation - Parotid Gland ANS Reflexes and Pharynx Sensation Posterior 1/3 Tongue External Ear

The Gag Reflex Sensory Part –Glossopharyngeal Motor Part –Vagus And Uvula Deviation ? cn9 cn10

Explain the different effects of UMN and LMN lesions of the hypoglossal nerve on tongue protrusion.

Damage to Cranial Nerve 12 Damage to the Lower Motor Neuron –Damage to Nerve or Nucleus –Tongue Deviate Toward the Lesion Damage to the Upper Motor Neurons –Damage to Corticobulbar Fibers –Tongue Deviates Away from the Lesion

Hypoglossal Lower Motor Neuron Damage Tongue Deviates Toward the Lesion –Damage to the Nucleus –Damage to the Nerve –Deviates to the Weak Side

Hypoglossal Upper Motor Neuron Damage Tongue Deviates Away from the Lesion Damage to Axons from the Cerebral Cortex –Motor Cortex (Lateral) –Internal Capsule –Corticobulbar Fibers Contralateral Termination

Upper Motor Neuron Lesion The Contralateral Tongue cannot Push! Deviates to the Weak Side

The Grand Finale The Case Faculty Evaluation Golden Neuron Quiz Your Questions Please Office Hours – Th and Friday – for Appointment next week – questions