Download Peripheral nerve

PNS I
Filip Barinka
PNS - divisions
• Somatic nervous system
• Autonomous nervous system
- Sympathetic
- Parasympathetic
• (Enteric nervous system)
Peripheral nerves
• Spinal nerves
• Cranial nerves
Fibers in peripheral nerve
• Efferent
- Somatic motor fibers
- Autonomous (motor) fibers
• Afferent
- Somatic sensitivity fibers
- Viscerosensitivity fibers
Picture from „Netter: Atlas of Neuroscience“
Schematic view of the spinal nerve!!!
For simplicity, meningeal branch is not marked
Some important concepts
• Area radicularis sensitiva – part of the
body, from which the sensory information is
led by one dorsal root of spinal nerve (or
one cranial nerve)
• Consists of DERMATOM (skin area) and
internal organs and muscles area, innervated
by the same dorsal root.
Dermatom
• Dermatoms form
longitudinal strips
on the surface of
the body.
Some important concepts
• Area radicularis motorica (Myotom) – muscles
innervated motorically by one ventral root of
spinal nerve (or one cranial nerve).
(But one muscle can by also innervated by
more than one ventral roots of spinal nerves.)
Area radicularis = area radicularis
sensitiva + area radicularis motorica
Some important concepts
• Area nervina – part of the body innervated
by one peripheral nerve. Some nerves form
nervous plexus and here, as a peripheral
nerve we mean the nerve distally to the
plexus from which it arises.
Spinal nerve
Spinal cord segment
Dorsal branch (ramus posterior)
Ventral branch (r. anterior)
Nerve plexus
„Peripheral
nerve“
Nerve plexus is allways formed only by ventral branches
of spinal nerves!
Nerve plexuses are
formed by ventral
branches of:
1. nerves C1-C4
Plexus cervicalis
2. nerves C5(C4)-Th1
Plexus brachialis
3. nerves Th12-L4
Plexus lumbalis
4. nerves L4-S5(Co)
Plexus sacralis
Picture from Petrovický a spol.: Systematická, topografická a klinická anatomie
Difference between dermatom ( or generally area radicularis
sensitiva) and area nervina (sensitiva)
Dermatom 1
Dermatom 2
Area nervina (sensitiva)
(Bodies of pseudounipolar neurons aren´t drawn in this scheme.)
Autonomous nervous system
• Has two portions- sympathetic and
parasympathetic nervous system. Both of
them are efferent (motor, or more accurately
visceromotor) and they innervate glands and
smooth muscles of internal organs and
vessels.
Autonomous nervous system
• Both of them consist of two neurons – the
first one is located in CNS, its axon runs to
the periphery and forms synapse with the
second neuron, which is located in the
autonomous (sympathetic or
parasympathetic) ganglion.
Variants of sympathetic
pathways.
b.)
a.)
c.)
d.)
Some additional
details
• Dorsal root leads
somatosensory,
Some additional
details
• Dorsal root leads
somatosensory,
but also
viscerosensory
information.