Anatomy: Intro to Cranial Nerves Flashcards
CN I
- Olfactory Nerve
- sensory- sense of smell
- Runs from the nasal mucosa (roof of nasal cavity along medial side of superior nasal concha
- Olfactory Organ - collection of epithelium
- Coalesce into filia olfactoria (olfactory fibers; these are the actual CN I)- these pass through cirbiform foramina
- Synapse on mitral cells in the bulb, project to forebrain via olfactory tract
Olfactory bulb and tract are part of what?
The brain, they are not actually the cranial nerve. The filia olfactoria are the nerves, which pass through the cribiform foramina and converge on bulb.
Olfactory tract projects where?
Forebrain, particualry limbic system- emotions, memory, visceral reflexes
Link between smells and memories/emotions
anosmia
- loss of smell
- commonly arises from nasal infections and ethmoid fractures
CN II
- Function- sensory for vision, various reflexes
- Course- ganglion cell fibers from retina join to form optic nerve, through optic canals and meet at optic chiasma, medial fibers dessucate, then to **Lateral Geniculate Nucleus of Thalamus **
CN IV
- Trochlear Nerve
- innervates Superior Oblique Muscle
- Passes through **Superior Orbital Fissure **
- Projects from Midbrain (pons) posteriorly and wraps around
CN V
- **Trigeminal Nerve **
- Projects from Pons (oversimplified)
- Trigeminal Ganglion- sensory ganglion on anterior surface of petrous part of temporal bone
Three Divisions
1. Opthalmic (CN V 1)
2. Maxillary (CN V2)
3. Mandibular (CN V3)
- From trigeminal ganglion (sensory ganglion)
Opthalmic Nerve
- CN V1
- sensory to face, orbital contents, scalp, sinues, dura
- through superior oribital fissure
Maxillary Nerve
- CN V2
- sensory to face, nasal cavities, palate, maxillary teeth and sinus, dura
- passes through foramen rotundum and pterygopalatine fossa
Mandibular Nerve
- CN V3
- Passes through Foramen Ovale to infratemporal Region
- Sensory to face, temporomandibular joint, mandibular teeth, tongue (ant 2/3), mouth, dura
- motor to muscles of mastication (also others)
Standing Room Only
S. Superior Orbital Fissue (opthalmic)
R. Foramen Rotundum (Maxillary)
O. Forarmen Ovale (Mandible)
Trigeminal Ganglion
sensory ganglion located on anterior surface of petrous part of
temporal bone in the trigeminal cave
Facial Nerve
Opthalmic Nerve
CN V 1
sensory from orbital, parts of face, scalp, nasal cavity, sinuses, dura
passes through superior orbital fissure
standing room only
Maxillary nerve
Sensory to parts of face, nasal cavities, palate, maxillary teeth, mxillary sinus, and dura
passes through foramen rotundum and pterygopalatine fossa
standing room only (Foramen Rotunda)
Mandibular Nerve
**Sensory ** to parts of face, temporomandibular joint, mandibular teeth, tongue (ant. 2/3), mouth, and dura
**motor ** to mm of mastication and others in first pharyngeal arch
passes through foramen ovale
standing room only- ovale
CN VI
- **Abduncent Nerve **
- Motor to **Lateral Rectus Muscle **
- Projects from Pons (Abducens Nucleus)
- passes through dura covering cilvus inside cavernous sinus then through superior orbital fissure
CN VII
- Facial Nerve
- Mixed and Parasympathetic
- Projects from **Pons **, through internal acoustic meatus, petrous part of temporal bone
- Forms geniculate ganglion (sensory neurons)
- Motor to Facial Exp. mm, 2nd pharyngeal arch
- sensory- anterior 2/3 of tongue
- parasympathetic inn to lacrimal, sublingual, submandibular
FORECASTING: The
facial nerve gives off
chordae typmani, which
merges with lingual n. to
provide parasympathetic
fibers to the submandibular
ganglion to stimulate
secretion of the sublingual
and submandibular glands
for salivation.
CN II Course
CN III
- Oculomotor N.
- Extraocular mm.- move eyeball and lift eyelid (Visceromotor, Parasympathetic)
- Preganglionic parasym. to ciliary ganglion
- postgang. sympathetic to superior tarsal mm
- passes through Superior Orbital Fissure
- innervates 4 of 6 extraocular mm
- Nuclei in Midbrain (Mesencephalon)
Superior tarsal mm is smooth muscle that joins Levator Palpebrae Superior and keep the eyelid open.
CN VIII
- Vestibulocochlear Nerve
- sensory- hearing (cochlear n.) and balance (vestibular n.)
- through internal acoustic meatus
- projects to 4 vestibular nuclei and 2 auditory nuclei in pons
CN IX
- Glossopharyngeal Nerve
- Mixed and parasypathetic
- Interfaces with Medulla (brainstem)
- Passes through **jugular foramen **
- Provides:
a. Motor innervation to the stylopharyngeus muscle derived from the 3rd pharyngeal arch
b. Parasympathetic secretomotor to parotid gland (remember it used auriculotemporal n.)
c. Sensory for taste on posterior 1/3 of the tongue
d. Sensory innervation from parts of oral cavity and middle ear
e. Sensory from the chemoreceptors and baroreceptors in the carotid body and sinus (with CN X)
CN X
- Vagus Nerve
- Mixed and Parasympathetic
- Passes through **Jugular Foramen **
- Interfaces with Medulla
5.
Provides:
a. Motor innervation to muscles from the 4th and 6th pharyngeal arches including laryngeal
muscles and some muscles of tongue, palate, and pharynx (thus swallowing function).
b. Parasympathetic innervation to smooth muscle and glands in pharynx, larynx, thoracic
and abdominal viscera.
c. Sensory innervation for taste from epiglottis.
d. General sensory innervation from viscera, larynx, parts of ear, and part of dura in the posterior
cranial fossa.
CN XI
- Accessory Nerve
2.Arises from upper cervical SC and enters through **Foramen Magnum ** - Exits through Jugular Foramen
- Motor to Trapezius and SCM
CN XII
- Inn ext and int tongue mm
- Arises from medulla
- exits through hypoglossal canal
