Summary of the Fiber Composition of Peripheral Nerves
I.
Nerve Fibers and the Locations of their Nerve Cells of Origin
The peripheral nervous system is made up of all parts of the nervous system except the
brain and spinal cord, which make up the central nervous system. The peripheral
nervous system consists of 1) the cranial nerves, 2) the spinal nerves, 3) the autonomic
nervous system. In the PNS all of the nerve fibers come from nerve cells in only four
different general locations. They are as follows:
1. Ganglia on cranial and spinal nerves- source of AFFERENT (sensory fibers).
[Afferent= conducting toward the CNS]
2. The ventral gray column and equivalent nuclei in the brain- source of EFFERENT
(motor) FIBERS TO SKELETAL MUSCLE. [Efferent= conducting away from the
CNS].
3. The Intermediolateral cell column and cranial and sacral equivalents- source of
PREGANGLIONIC EFFERENT fibers to autonomic ganglia.
4. Autonomic ganglia- source of POSTGANGLIONIC EFFERENT fibers to smooth
muscle, cardiac muscle, and glands.
Therefore, there are basically only four different types of nerve fibers in the peripheral
nervous system, one afferent and three efferent. Although some of these four basic
types can be subdivided, using such terms as special and general, somatic and visceral,
we will not do so here. Because of their atypical nature, cranial nerves I and II are
omitted from the following discussion of fiber types.
A. AFFERENT FIBERS- cells are located in ganglia on cranial and spinal nerves. Excluding
cranial nerves I and II, all afferent fibers in the PNS come from one of the following
ganglia:
Nerves Containing afferent fibers
Location of cell bodies
V. Trigeminal
Trigeminal Ganglion
Mesencephalic Nucleus of V (proprioceptive of
muscles of mastication)
Geniculate ganglion
Vestibular Ganglion
Spiral Ganglion
Superior Ganglion
Inferior Ganglion
Superior (Jugular) ganglion
Inferior (Nodose) ganglion
Dorsal Root Ganglia
VII. Facial
VIII. Vestibulocochlear
IX. Glossopharyngeal
X. Vagus
All spinal nerves
B. EFFERENT FIBERS TO SKELETAL MUSCLE- cells are located in the ventral gray
column of the spinal cord and in equivalent nuclei (collections of nerve cells) in the
brainstem. All efferent fibers to skeletal muscle come from one of the following places:
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Nerve Containing Efferent Fibers to
Skeletal Muscle
Location of Cell Bodies- Nuclei
III. Oculomotor
IV. Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII. Hypoglossal
Spinal nerves
Oculomotor Nucleus
Trochlear Nucleus
Motor Nucleus of the Trigeminal Nerve
Abducens Nucleus
Facial Nucleus
Nucleus Ambiguus
Nucleus Ambiguus
Spinal Nucleus of Accessory Nerve
Hypoglossal Nucleus
Ventral Gray Column of spinal cord
Location of Cell Bodies
Peripheral Termination
Oculomotor Nucleus
Levator palpebrae superioris, Superior rectus,
medial rectus, inferior rectus, inferior oblique
Superior oblique
Masseter, temporalis, lateral pterygoid, medial
pterygoid, mylohyoid, anterior belly of digastric,
tensor veli palatini, tensor tympani.
Lateral rectus
Muscles of facial expression, stylohyoid, posterior
belly of digastric, stapedius.
Stylopharyngeus
Muscles of palate (except tensor), muscles of
pharynx (except stylopharyngeus), muscles of
larynx, upper esophagus.
Sternocleidomastoid, trapezius
Intrinsic muscles of tongue, all glossus muscles
except palatoglossus.
Trochlear Nucleus
Motor Nucleus of Trigeminal Nerve
Abducens Nucleus
Facial Nucleus
Nucleus Ambiguus (IX)
Nucleus Ambiguus (X)
Spinal nucleus of XI
Hypoglossal Nucleus
C. PREGANGLIONIC EFFERENT FIBERS- cells of origin are located in the
Intermediolateral cell column of the thoracic and upper lumbar segments of the spinal cord
and in equivalent nuclei in the brain stem and in the sacral spinal cord. All preganglionic
efferent fibers come from one of the following places:
Nerve containing preganglionic efferent
fibers
Location of Cell Bodies
III. Oculomotor
VII. Facial
IX. Glossopharyngeal
X. Vagus
T1-L2 Spinal Nerves
S2-S4 Spinal Nerves
Nucleus of Edinger-Westphal
Superior Salivatory Nucleus
Inferior Salivatory Nucleus
Dorsal Motor Nucleus of Vagus
Intermediolateral Cell Column
Sacral autonomic nucleus (intermediate gray of
the sacral spinal cord)
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D. POSTGANGLIONIC EFFERENT FIBERS- cells of origin are located in autonomic
ganglia. These cells all receive the terminations of preganglionic efferent fibers from cells
in one of the locations listed in C) above. All postganglionic efferent fibers come from
cells in one of the following ganglia:
Source of preganglionic Efferent fibers
to ganglion
Name of ganglion containing cell bodies
of postganglionic efferent fibers
Nucleus of Edinger-Westphal
Superior Salivatory Nucleus
Superior Salivatory Nucleus
Inferior Salivatory Nucleus
Dorsal Motor Nucleus of Vagus
Ciliary
Pterygopalatine
Submandibular
Otic
Terminal (in organs of thorax and abdomen down
to splenic flexure of colon)
Sympathetic (ganglia of sympathetic trunk +
collateral or Prevertebral ganglia) + cells in
adrenal medulla
Terminal (in organs of pelvis + descending colon)
Intermediolateral Cell Column
Sacral autonomic nucleus
Postganglionic efferent fibers terminate peripherally in smooth muscle, cardiac muscle,
or glands. The peripheral terminations of postganglionic efferent fibers are as follows:
Locations of Cell Bodies
Peripheral Termination
*Ciliary Ganglion
*Pterygopalatine ganglion
Ciliary muscle + sphincter pupillae
Lacrimal gland + glands of the nasal cavity and
the palate
Submandibular gland + sublingual gland
Parotid Gland
Cardiac muscle, smooth muscle of coronary
arteries, smooth muscle of bronchi, smooth
muscle and glands of alimentary canal down to
splenic flexure
Dilator pupillae, smooth muscle in blood vessels,
smooth muscle in hair follicles (arrector pili),
sweat glands, cardiac muscle, smooth muscle of
viscera (generally inhibitory except for sphincters)
Smooth muscle and glands in descending colon
and pelvic viscera
*Submandibular Ganglion
*Otic Ganglion
*Terminal Ganglia
Sympathetic Ganglia
*Terminal Ganglia (sacral)
* Note: The pre and postganglionic efferent fibers associated with the Ciliary, Pterygopalatine,
Submandibular, otic, and terminal ganglia make up what is known as the parasympathetic
division of the Autonomic nervous system. This division is also called the craniosacral
division because of the preganglionic nerve cells are located in either the brainstem or the
sacral spinal cord and their fibers are distributed through either cranial (III, VII, IX, X) or
sacral (S2, S3, or S4) nerves. The sympathetic (thoracolumbar) division of the ANS is made up
of the pre and postganglionic efferent fibers associated with the sympathetic ganglia.
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II.
Classification of Cranial Nerves
A. Afferent (sensory)
1. Olfactory (CN I)
2. Optic (CN II)
3. Vestibulocochlear (CN VIII)
B. Efferent (motor)
1. Oculomotor (CN III)
2. Trochlear (CN IV)
3. Abducens (CN VI)
4. Accessory (CN XI)
5. Hypoglossal (CN XII)
C. Mixed (sensory and motor)
1. Trigeminal (CN V)
2. Facial (CN VII)
3. Glossopharyngeal (CN IX)
4. Vagus (CN X)
III.
Summary of Cranial Nerves
A.Olfactory (CN I)
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Afferent
Olfactory mucosa
Olfactory mucosa
B. Optic (CN II)- The optic nerve is a tract of the brain connecting the retina, which is
embryologically an outgrowth of the brain. It is made up almost entirely of afferent
fibers which arise from the ganglion cells in the retina.
C. Oculomotor (CNIII)
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Efferent to skeletal muscle
Oculomotor Nucleus
Preganglionic
Nucleus of Edinger-Westphal
All extraocular muscles except
superior oblique and lateral
rectus
Ciliary Ganglion
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Efferent to skeletal muscle
Trochlear nucleus
Superior oblique Muscle
D. Trochlear (CN IV)
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E. Trigeminal (CN V)- The trigeminal nerve is the nerve of the first branchial arch
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Afferent (general sensation)
Trigeminal Ganglion
Afferent (Proprioception)
Efferent to skeletal muscle
Mesencephalic Nucleus of V
Motor nucleus of V
Skin of face and anterior half of
scalp, the orbit and eyeball, the
mucosa of the nasal cavity,
paranasal sinuses, and the oral
cavity, including the body of the
tongue (except for taste), upper
and lower jaws, including teeth,
cranial dura mater.
Muscles of mastication
Muscles of mastication,
mylohyoid, anterior belly of
digastric, tensor veli palatini,
tensor tympani
F. Abducens (CN VI)
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Efferent to skeletal muscle
Abducens nucleus
Lateral rectus (abducts the eye)
G. Facial (CN VII)- The facial nerve is the nerve of the second gill arch
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Efferent to skeletal muscle
Facial nucleus
Afferent
Geniculate Ganglion
Preganglionic
Superior Salivatory Nucleus
Muscles of facial expression,
stylohyoid, posterior belly of
digastric, stapedius
Taste buds on anterior 2/3 of
tongue, external acoustic
meatus, soft palate and adjacent
pharynx.
Pterygopalatine Ganglion,
Submandibular Ganglion
H. Vestibulocochlear (CN VIII)
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Afferent
Spiral Ganglion
Afferent
Vestibular Ganglion
Hair Cells in Spiral Organ (of
Corti)
Hair cells in maculae of saccule
and utricle and cristae of
semicircular ducts
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I. Glossopharyngeal (CN IX)- the glossopharyngeal nerve is the nerve of the third
branchial arch
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Afferent
Inferior Ganglion
Efferent to skeletal muscle
Preganglionic efferent
Nucleus Ambiguus
Inferior Salivatory Nucleus
Taste buds on posterior 1/3 of
tongue including the sulcus
terminalis and the vallate
papillae; mucosa of posterior 1/3
of tongue, oropharynx, and the
soft palate; carotid sinus and
carotid body
Stylopharyngeus
Otic Ganglion
J. Vagus (CN X)- The vagus nerve is the nerve of the fourth and sixth branchial arches.
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Afferent
Afferent
Superior Ganglion
Inferior Ganglion
Preganglionic efferent
Dorsal Motor Nucleus of Vagus
Efferent to skeletal muscle
Nucleus Ambiguus
Skin of external acoustic meatus
Mucosa of larynx, epiglottis
(taste buds), trachea, bronchi,
lungs, alimentary canal down to
left colic flexure.
Terminal ganglia in thoracic and
abdominal viscera down to left
colic flexure
Muscles of palate except tensor
veli palatini, muscles of pharynx
except stylopharyngeus; all
muscles of larynx; upper
esophagus
K. Accessory (CN XI)
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Efferent to skeletal muscle
Spinal nucleus of accessory
nerve
Sternocleidomastoid, Trapezius
L. Hypoglossal (CN XII)
Types of Fibers
Location of Cell Bodies
Peripheral Termination
Efferent to skeletal muscle
Hypoglossal nucleus
Intrinsic muscles of tongue,
genioglossus, hyoglossus,
styloglossus
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