Transcript Cervical Plexus

中枢/外周神经功能分类.
♠ Sensory division brings information regarding the
int. or ext. environment into the CNS
♠ Motor division issues directives out to muscle or
glandular tissue
♣Somatic nervous system services skeletal muscle
♣ Autonomic nervous system services smooth
&cardiac muscle:
♦ Sympathetic nervous system is responsible for the "fightor-flight"response;
♦ Parasympathetic nervous system is responsible for the
"rest-anddigest"response
Divisions of the
Nervous System
• Central Nervous System
• Peripheral Nervous System
• nerves
• cranial nerves
• spinal nerves
The Spinal Nerves
1. General Description
31 Pairs of Spinal Nerves
Cervical Nerves : 8 pairs
Thoracic Nerves : 12 pairs
Lumbar Nerves : 5 pairs
Sacral Nerves : 5 pairs
Coccygeal Nerves : 1 pair
Four types of fibers in spinal Nerves
Two Roots : anterior root--motor fibers;
posterior root--sensory fibers
Somatic efferent[motor]fibers; Visceral
efferent [motor] fibers
Four branches of a spinal nerves
Anterior branch ; posterior branch
Meningeal branch; communicating
branches
Four plexuses
Cervical plexus颈丛
Brachial plexus臂丛
Lumbar plexus腰丛
Sacral plexus骶丛
The thoracic nerves are
separated from each
other.
Cervical Plexus
• The cervical plexus is formed by ventral rami of
C1-C4
• Most branches are cutaneous nerves of the neck,
ear, back of head, and shoulders
• The most important nerve of this plexus is the
phrenic nerve
• The phrenic nerve is the major motor and
sensory nerve of the diaphragm
• The cervical plexus is formed from ventral
rami of the first 4 cervical nerves, buried
deep in neck below the sternocleidomastoid
muscle
• Cervical plexus produces mostly cutaneous
nerves serving skin of the ears,neck &
shoulder
• Also forms phrenic nerve serving the
diaphragm
The cervical Plexus
• The Formation of the Cervical Plexus:
• The anterior branches of the 1st to 4th cervical
nerves (C1~4)
Brachial Plexus
Formed by C5-C8 and T1 (C4 and T2 may also
contribute to this plexus)
It gives rise to the nerves that innervate the
upper limb
Axillary – innervates the deltoid and teres
minor
Median – branches to most of the flexor
muscles of arm
Ulnar – supplies the flexor carpi ulnaris and
part of the flexor digitorum profundus
Radial – innervates essentially all extensor
muscles
The Brachial Plexus (scalene fissure, axilla)
formation: root(C5 – T1)
Radial Nerve
The Anterior Branches of the Thoracic
Nerves
——Intercostal and subcostal
nerve
The segmental distribution of the anterior branches of
the thoracic nerves
T2: the sternal angle
T8: the costal arch
T4: the nipple
T10: the umbilicus
T6: the xiphoid process
T12: the anterior
superior iliac spin
The Lumbar Plexus
• The formation of the lumbar plexus:
T12 (part)+L1~3+L4 (part)
The branches of the lumbar plexus
The iliohypogastric nerve
The ilioinguinal nerve
The lateral femoral
cutaneous nerve
The femoral nerve
The obturator nerve
The genitofemoral nerve
The Sacral Plexus
• The formation of the sacral plexus
The lumbosacral trunk(L4~5)+S1~5+Co
The branches of the sacral plexus
–The superior gluteal n.
–The inferior gluteal n.
–The pudendal n.
– The posterior femoral
cutaneous n.
The sciatic nerve
The branches of
the sacral plexus
The sciatic nerve
(Poplited fossa)
•The tibial nerve
•(hook-like foot)
•The common peroneal
nerve
(talipes equinovarus)
The superficial peroneal
nerve
The deep peroneal nerve
Autonomic System
• Two divisions:
– Sympathetic nerve交感神经
– Parasympatheitic nerve副交感神经
• Control involuntary functions
–
–
–
–
–
heartbeat
blood pressure
respiration
perspiration
digestion
• Can be influenced by thought and emotion
Sympathetic
• “ Fight or flight”
response
• Release adrenaline
and noradrenaline
• Increases heart rate
and blood pressure
• Increases blood
flow to skeletal
muscles
• Inhibits digestive
functions
CENTRAL NERVOUS SYSTEM SYMPATHETIC
Brain
Dilates pupil
Stimulates salivation
Relaxes bronchi
Spinal
cord
Salivary
glands
Lungs
Accelerates heartbeat
Inhibits activity
Heart
Stomach
Pancreas
Stimulates glucose
Secretion of adrenaline,
nonadrenaline
Relaxes bladder
Sympathetic Stimulates ejaculation
ganglia
in male
Liver
Adrenal
gland
Kidney
Parasympathetic
• “ Rest and digest ”
system
• Calms body to
conserve and
maintain energy
• Lowers heartbeat,
breathing rate,
blood pressure
CENTRAL NERVOUS SYSTEM PARASYMPATHETIC
Brain
Contracts pupil
Stimulates salivation
Spinal
cord
Constricts bronchi
Slows heartbeat
Stimulates activity
Stimulates gallbladder
Gallbladder
Contracts bladder
Stimulates erection
of sex organs
Summary of autonomic
differences
Autonomic nervous system controls physiological arousal
Sympathetic
division (arousing)
Pupils dilate
Decreases
Parasympathetic
division (calming)
EYES
Pupils contract
SALVATION
Increases
Perspires
SKIN
Dries
Increases
RESPERATION
Decreases
Accelerates
HEART
Slows
Inhibits
DIGESTION
Activates
Secrete stress
hormones
ADRENAL
GLANDS
Decrease secretion
of stress hormones
Sympathetic Division
• Myelinated preganglionic exit spinal cord in
ventral roots at T1 to L2[L3] levels.
• Travel to ganglia at different levels to synapse
with postganglionic neurons.
• Divergence:
– Preganglionic fibers branch to synapse with
numerous postganglionic neurons.
Sympathetic Division
• Axons of postganglionic neurons are
unmyelinated to the effector organ.
• Preganglionic neuron is short.
• Post-ganglionic neuron is long.
Parasympathetic Division
• Preganglionic fibers originate in midbrain,
medulla, and pons; and in the 2-4 sacral
levels of the spinal cord.
• Preganglionic fibers synapse in ganglia
located next to or within organs innervated.
• Do not travel within spinal nerves.
– Do not innervate blood vessels, sweat glands,and
arrector pili muscles.
Parasympathetic Division
• 4 of 12 pairs of cranial nerves contain
preganglionic parasympathetic fibers.
• Preganglionic fibers are long,
postganglionic fibers are short.
• Vagus:
– Innervate heart, lungs esophagus, stomach,
pancreas, liver, small intestine and upper half of
the large intestine.
Parasympathetic Division
• Preganglionic fibers from the sacral
level innervate the lower half of large
intestine, the rectum, urinary and
reproductive systems.