Cranial Nerves

Front 1

1.1. Olfactory - I

Back 1

1.1.1. Forebrain
1.1.2. Doesn’t pass through Thalamus
1.1.3. Oldest phylogenically
1.1.4. Most poorly understood
1.1.5. Only cranial nerve attached directly to the cerebrum
1.1.6. The cranial nerve is invisible within the bony perorations of the cribiform plate of the ethmoid bone.

Front 2

1.2. Optic - II

Back 2

1.2.1. Diencephalon
1.2.2. Includes whole optic tract and retina
1.2.3. Vision
1.2.4. Optic chiasm divides two parts, the nerve and the tract, but all part of same CNS
1.2.5. Only partial crossing of the nerve

Front 3

1.3. Oculomotor – III

Back 3

1.3.1. Midbrain
1.3.2. First “real” peripheral nerve
1.3.3. Drives all muscles of the eye except (lateral rectus & superior oblique)
1.3.4 Midline, below mamillary body
1.3.5. Reflexes of the eye (e.g. Vestibulo-ocular reflex which stabilizes the eye during head movement)
1.3.6. Visceral efferent pre-ganglionic parasympathetic neurons in the edinger-westphal nucleus
1.3.7. Post-ganglionic fibers originate in the cilliary ganglion
1.3.8. Controls Iris, and Lense of the eye
1.3.9. Somatic motor – conscious
1.3.10. Visceral motor - unconscious

Front 4

1.4. Trochlear - IV

Back 4

1.4.1. Moves one muscle of the eye – the superior oblique
1.4.2. Only to emerge from dorsal aspect of the brainstem

Front 5

1.6. Abducens – VI

Back 5

1.6.1. Pons
1.6.2. Laterally rotates the eye (lateral rectus)
1.6.3 “Abducts”

Front 6

1.7. Facial/intermediate – VII

Back 6

1.7.1. Pons
1.7.2. Motor nerve driving facial expression
1.7.3. Taste – sensory
1.7.4. Facial expression – motor
1.7.5. One of the 5 serving the tongue (V, IX, XI, XII)
1.7.6. Branchiomeric efferent: muscles of facial expression, middle ear reflexes (stapedius)
1.7.7. Efferent to stylohyoid muscle – elevate hyoid bone during swallowing
1.7.8. Visceral Efferent: Superior salivatory and lachrymal nuclei
1.7.9. Believed to have brought about some level of speech in human evolution
1.7.10. Pterygopalatine ganglion-lacrimal and submandibular glands
1.7.11. Visceral afferent: gustatory input from anterior 2/3 of the tongue, via geniculate ganglion

Front 7

1.8. Vestibulicochlear – VIII

Back 7

1.8.1. Pons
1.8.2. Balance & equilibrium, hearing – sensory
1.8.3. The only cranial nerves that carries two sensory modalities
1.8.4. Hearing – modified mechano-receptor

Front 8

1.9. Glossopharyngeal – IV

Back 8

1.9.1. Medulla
1.9.2. Mostly sensory, but is mixed
1.9.2.1. Motor, sensory, pre-ganglionic innervations to sympathetic/parasympathetic glands
1.9.3. Tongue, pharynx – sensory
1.9.4. Swallowing, salivary gland – motor
1.9.5. Visceral efferent to smooth muscle in duct of gland
1.9.6. Branchiomeric efferent – nucleus ambiguous stylopharyngeus muscle
1.9.7. Visceral efferent – inferior salivatory nucleus
1.9.8. Parasympathetic motor via otic ganglion to parotid salivary gland
1.9.9. Somatic afferent – pain, temp from skin around ear via superior ganglion of IX
1.9.10. Visceral Afferent
1.9.10.1 solitary nucleus
1.9.10.2 sense of posterior 1/3 of tongue
1.9.10.2.1 via the inferior ganglion

Front 9

1.10. Vagus – X

Back 9

1.10.1. Medulla
1.10.2. PNS equivalent of the trigeminal
1.10.3. Primary parasympathetic information nerve
1.10.4. Visceral sensory branches, radiates esophagus, respiratory tract, abdominal viscera, large intestine - Sensory
1.10.5. Heart, smooth muscles, glands, respiratory tract, stomach, intestines, gallbladder – Motor
1.10.6. Branchiomeric efferent (innervates muscles of 4th and 6th arch, most of pharanyx and palate)
1.10.6.1 Nuclear ambiguous motor to pharynx and larynx
1.10.7. General Visceral Efferent
1.10.7.1 Dorsal motor nucleus
1.10.7.2 Thoracic and abdominal viscera via pregang. near target
1.10.8. Special Visceral Afferent
1.10.8.1. Solitary nucleus
1.10.8.2 Taste epiglottis via inferior nodose ganglion
1.10.9. General Visceral Afferent
1.10.9.1 Solitary, touch, pain, temp-pharynx, larynx, thorax, abdomen via nodose ganglion
1.10.10. General Somatic Afferent
1.10.10.1 Touch, pain, temperature, skin of ear, external auditory meatus via superior ganglion of nerve X

Front 10

1.11. Accessory – XI

Back 10

1.11.1. Medulla
1.11.2. Swallowing, vocal chords, muscles of neck and back (sternocleidomastoid and trapezius)– Motor

Front 11

1.12. Hypoglossal - XII

Back 11

1.12.1. Medulla
1.12.2. Tongue movements – Motor
1.12.3. All tongue muscles except palatoglossus muscle (CN X Vagus)

Front 12

1.5. Trigeminal – V

Back 12

1.5.1. Pons
1.5.2. Sensory nerve of the face
1.5.3. 3 Branches
1.5.3.1. Ophthalmic nerve (V1): carries sensory information from the scalp and forehead, the upper eyelid, the conjunctiva and cornea of the eye, the nose (including the tip of the nose, except alae nasi), the nasal mucosa, the frontal sinuses, and parts of the meninges (the dura and blood vessels).
1.5.3.2. Maxillary nerve (V2): carries sensory information from the lower eyelid and cheek, the nares and upper lip, the upper teeth and gums, the nasal mucosa, the palate and roof of the pharynx, the maxillary, ethmoid and sphenoid sinuses, and parts of the meninges.
1.5.3.3. Mandibular nerve (V3): carries sensory information from the lower lip, the lower teeth and gums, the chin and jaw (except the angle of the jaw, which is supplied by C2-C3), parts of the external ear, and parts of the meninges. The mandibular nerve carries touch/position and pain/temperature sensation from the mouth. It does not carry taste sensation (chorda tympani is responsible for taste), but one of its branches, the lingual nerve, carries multiple types of nerve fibers that do not originate in the mandibular nerve.
1.5.4. Special sensory – some taste fibers of throat
1.5.5 The trigeminal complex is analogous to the dorsal columns AND the spinothalamic system in that it supplies somatosensation, epicritic touch as well as pain, temp, itch, and proprioception, to the region of the head.