Since you may not have a general knowledge of the nervous system yet, consider the following as a general introduction into what kind of modalities are possible with nerves. A modality is unit of the nervous system that performs a certain type of action: sensation, movement, constriction, etc. There are two general modalities in the peripheral nervous system: motor (efferent) and sensory (afferent). Efferent impulses start in the central nervous system and pass peripherally in spinal or cranial nerves. Afferent impulses start out peripherally and pass into the central nervous system.
Since we are considering cranial nerves here, this is what we will concentrate on. There are 12 pairs of cranial nerves that supply structures in the head, neck, thorax and abdomen. A cranial nerve can be made up of a mixture of functions which are called modalities or may be made up of a single modality. A modality is sensory, motor, special sensory, etc. Below is a breakdown of the modalities of cranial nerves. You may never need to learn this terminology but it is being presented just in case.
(motor) |
(sensory) |
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General somatic
efferent |
General visceral efferent | Special visceral efferent | General somatic afferent | Special somatic afferent | General visceral afferent | Special visceral afferent |
GSE -- motor to skeletal muscles
GVE -- motor to heart muscle, smooth muscle, glands. In the cranial nerves, these impulses are part of the parasympathetic nervous system.
SVE -- motor to skeletal muscles that develop in branchial arches of the embryo (pharynx, larynx, middle ear)
GSA -- sensations of touch, pain, temperature
SSA -- special sense from organs developing in ectoderm of embryo (vision, hearing)
GVA -- sensory from sensory organs (heart, intestine)
SVA -- special sense from organs developing in association of gastrointestinal tract (smell, taste)
Nerve |
Exit From Skull |
Foramen |
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Impulse |
Supplied and Function |
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cribriform plate | none | olfactory filaments | special sensory (afferent) | nasal mucosa, smell |
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optic foramen | none | none | special sensory (afferent) | retina, vision |
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superior orbital fissure | none | superior
division
inferior division |
general motor (efferent)
parasympathetic motor |
muscles: superior rectus,
levator palpebrae superioris
muscles: medial rectus, inferior rectus, inferior oblique, parasympathetic to ciliary ganglion for pupillary constriction |
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superior orbital fissure | none | muscular | motor (efferent) | superior oblique muscle |
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see below | see below | see below | general motor (efferent)
general sensory (afferent) |
see below |
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superior orbital fissure | supraorbital foramen
anterior & posterior ethmoidal foramina |
meningeal, frontal, lacrimal, nasociliary | general sensory (afferent) | sensation from dura, skin of forehead, scalp, roof of nasal cavity and skin on tip of nose, ethmoid air cells |
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foramen rotundum | inferior orbital fissure
infraorbital foramen |
meningeal, infraorbital, posterior & anterior superior alveolar branches, zygomatic, sensory roots to pterygopalatine ganglion, greater & lesser palatine | general sensory (afferent) | sensation from dura, nasal mucosa, soft palate, skin of lower eyelid and beneath the eye, side of nose, cheek, lip, upper teeth, hard palate |
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foramen ovale | mandibular foramen | meningeal, auriculotemporal,
buccal, lingual
inferior alveolar |
general sensory (afferent)
general motor (efferent) |
sensation from dura, anterior
ear and scalp,
mucosa lining cheek and gums, skin of cheek, lower teeth, skin of chin, general sensation to the anterior 2/3 of the tongue. motor to temporalis, masseter, medial pterygoid, lateral pterygoid, anterior belly of digastric, mylohyoid, tensor palati, and tensor tympani. |
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superior orbital fissure | none | muscular | general motor (efferent) | lateral rectus muscle |
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internal auditory meatus | hiatus of facial canal
facial canal stylomastoid foramen |
greater petrosal nerve,
chorda tympani
auricular branch, facial branches, cervical branches |
special and general sensory
(afferent)
general and parasympathetic motor (efferent) |
sensation of taste for anterior
2/3 tongue, skin from external meatus, taste from palate.
motor to muscles of facial expression, stapedius muscle, muscles of auricle, parasympathetic motor to pterygopalatine ganglion for lacrimal secretion, motor to submandibular ganglion to submandibular and sublingual glands for secretion. |
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internal auditory meatus | none | vestibular, cochlear | general sensory (afferent) | sensation from cochlea for
hearing and from
semicircular canals and vestibule for equilibrium |
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jugular foramen | muscular branches, auricular branch, lingual branch, branch to carotid body and sinus, tympanic branch, lesser petrosal | general and special sensory
(afferent)
general and parasympathetic motor (efferent) |
special sensation of taste
from posterior 1/3 of tongue, general sensation from the oropharynx, posterior
1/3 of tongue, sensation from pharyngeal mucosa, special sensation from
carotid body and sinus.
general motor to stylopharyngeus muscle, parasympathetic to the otic ganglion for parotid gland secretion. |
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jugular foramen | none | palatopharyngeal branch, superior laryngeal branch, recurrent laryngeal branch, carotid sinus nerve, cardiac, pulmonary, gastric, renal, hepatic, pancreatic, small intestine, large intestine branches. | sensory (afferent)
motor (efferent) |
special sensation of
taste from base of tongue and epiglottis, general sensation from soft palate,
upper larynx, special sensation form carotid body.
motor to muscles of soft palate (except tensor palati), muscles of pharynx (except for stylopharyngeus), muscles of larynx, cardiac muscle, smooth muscle of lungs, muscles of intestinal tract as far as the left colic flexure.. |
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jugular foramen | foramen magnum | muscular | motor (efferent) | cranial part: provides motor
to vagus
spinal part: sternomastoid and trapezius muscles |
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hypoglossal foramen | none | muscular | general motor (efferent) | motor to styloglossus, hyoglossus, genioglossus and intrinsic muscles of the tongue. |
Now, take a look at what I call cranial
nerve maps. These are icons of cranial nerves, their branches, what they
supply and what foramina they use. Sensory is yellow
and motor is red. Solid red is for skeletal
muscle. Dashed red is for parasympathetic fibers. You sort of have to memorize
which nerves have motor or sensory or both modalities, then consider what
part of the head and neck is involved with each nerve. For example, when
you look at the olfactory road map, you will see that it is yellow which
means it is purely sensory. Then you consider what kind of sensation of
picked up in the periphery which, in this case, is smell. The smell impulses
then go back to the central nervous system. If there is red included in
the map, that means that something will receive efferent fibers and will
either contract or secrete. The impulse starts out in the central nervous
system and passes out to a muscle or gland.
You will probably develop your own approach
to remembering the cranial nerves and their branches and what they do but
this is one method to consider.
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cp--cribriform plate
of ethmoid |
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on--optic nerve
oc--optic chiasm ot--optic tract |
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sof--superior orbital fissure
sd--superior division sr--superior rectus id--inferior division mr--medial rectus io--inferior oblique ir--inferior rectus cg--ciliary ganglion sc--short ciliary nerves |
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so--superior oblique |
![]() Red solid -- motor to skeletal muscles Red dotted -- parasympathetic motor to cardiac and smooth muscle Yellow -- sensory (afferent) |
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sof--superior orbital fissure |
![]() Red solid -- motor to skeletal muscles
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iam--internal auditory (acoustic) meatus |
![]() Red solid -- motor to skeletal muscles Red dotted -- parasympathetic motor to cardiac and smooth muscle Yellow -- sensory (afferent) |
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![]() Red solid -- motor to skeletal muscles
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Larynx![]() |
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Copyright© 1999 by Wesley Norman, PhD, DSc |