Download THE NERVOUS SYSTEM

THE PERIPHERAL
NERVOUS SYSTEM
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
 Two
Roots of Spinal Nerves
– Anterior Root: motor fibers
– Posterior Root: sensory fibers
 Four Types
of Fibers in Spinal Nerves
– The Somatic afferent (sensory) Fibers
- The Visceral afferent (sensory) Fibers
– The Somatic efferent (motor) Fibers
- The Visceral efferent (motor) Fibers
 Four Branches
of a Spinal Nerves
– Anterior Branch
Posterior Branch
– Meningeal Branch Communicating Branches
Four Branches of a Spinal Nerves
 Four Plexuses
– Cervical Plexus
– Brachial Plexus
– Lumbar Plexus
– Sacral Plexus

The thoracic nerves
are separated from
each other.
The cervical Plexus

The Formation of the Cervical Plexus:

The anterior branches of the 1st to 4th cervical
nerves (C1~4)
• The Superficial Branches
（sternocleidomastoid m.)
The lesser occipital nerve
The great auricular nerve
The transverse nerve of neck
The supraclavicular nerves

The Deep Branches
– The phrenic nerve
The Brachial Plexus (scalene fissure, axilla)
 formation: root(C5 – T1)
trunk
division
cord
branches and distribution
Brachial plexus : the long thoracic
lateral cord
Medial cord
Posterior cord
the musculocutaneous nerve
lateral pectoral nerve
the median nerve
the ulnar nerve
medial pectoral nerve
the radial nerve
the axillary nerve
the thoracodorsal nerve
the musculocutaneous n.
the axillary n.
the long thoracic n.
median n.
the ulnar n.
medial pectoral n.
lateral pectoral n.
the radial n.
the thoracodorsal n.
the long thoracic n.
serratus anterior
the musculocutaneous nerve
anterior group of the arm
lateral pectoral nerv
the pectoralis major
medial pectoral nerv
pectoralis minor
the median nerve
the most of anterior group of the
forearm and part muscles of hand
the ulnar nerve
the part of anterior group of the
forearm and part muscles of hand
the radial nerve
posterior group of arm and posterior
group of the forearm
the axillary nerve
the thoracodorsal nerve
deltoid
latissimus dorsi
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 femoral nerve
The ilioinguinal nerve
The obturator nerve
The lateral femoral cutaneous 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 anal nerves
The perineal nerve
The dorsal nerve of
penis or clitoris
The branches of
- The the
posterior
femoral
sacral plexus
cutaneous n.
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