2. Nerve Plexuses
• Complex, interwoven networks of nerve
fibers
• Formed by blended fibers of ventral rami
of adjacent spinal nerves
• Mixed nerves.
• Control muscles of the neck and upper
and lower extremities
• Receive sensory information from skin
superficial to muscles.
3. Nerve Plexuses
The four major plexuses made from ventral
rami
1. Cervical plexus
2. Brachial plexus
3. Lumbar plexus
4. Sacral plexus
4. Nerve Plexuses
• Cervical Plexus
▫ Includes ventral rami of spinal nerves C1 –
C5
▫ Innervates muscles of the neck, thoracic
cavity and diaphragm
▫ Major nerve
Phrenic nerve - innervates the diaphragm and
contains fibers from C3, C4, and C5.
6. Nerve Plexuses
• Brachial Plexus
▫ Includes ventral rami of spinal nerve roots
C5 – T1
▫ Innervates pectoral girdle and upper limbs
▫ Nerves that form brachial plexus originate
from
Superior, middle, and inferior trunks
Anterior and posterior divisions
Lateral, medial , and anterior cords
Smaller branches or named nerves, innervate
muscles
7. Nerve Plexuses
• Brachial Plexus
▫ Major nerves of brachial plexus
Musculocutaneous nerve – innervates biceps brachii
Median nerve – innervates most flexors of the
forearm
Ulnar nerve – innervates medial portions of the
hand
Axillary nerve – innervates the deltoid
Radial nerve – innervates most extensors of the arm
and forearm
10. Nerve Plexuses
• Lumbar Plexus
▫ Includes ventral rami of spinal nerves T12 –
L4
▫ Major nerves
Obturator nerve – innervates the adductors of
the hip
Femoral nerve - innervates the quadriceps
femoris muscle group
12. Nerve Plexuses
• Sacral Plexus
▫ Includes ventral rami of spinal nerves L4 –
S4
▫ Major nerve
Sciatic nerve – longest and largest nerve in
the PNS
Innervates the flexors of the knee and foot
Branches into
▫ Fibular nerve – innervates part of the hamstrings
and anterior tibialis m.
▫ Tibial nerve – innervates part of the hamstrings
and the gastrocnemius and soleus mm.