Slide presentation on the four nerve plexuses.

1. Spinal Nerves and
Spinal Plexuses
SLIDES AND NARRATION BY MARY KLINGER

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.

5. Nerve Plexuses
• Picture of cervical plexus in situ:

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

8. Nerve Plexuses
Picture
of
Brachial
Plexus
in Situ

9. Nerve Plexuses
• Picture of brachial plexus

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

11. Nerve Plexuses
Picture of
Lumbar
Plexus

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.

13. Nerve Plexuses
Picture
of the
Sacral
plexus