This document summarizes the cranial and spinal nerves. It describes the 12 pairs of cranial nerves including their classification, origin, and destination. It also discusses the four principal plexuses where spinal nerves merge - the cervical, brachial, lumbar, and sacral plexuses. Finally, it outlines the major nerves of the extremities including the nerves of the arm and leg.

1. CRANIAL
&
SPINAL NERVES
MAJ DR RISHI POKHREL
DEPT OF ANATOMY
NAIHS

2. Sensory ReceptorsSensory Receptors
Motor EndingsMotor Endings
Cranial NervesCranial Nerves
The Four PlexusesThe Four Plexuses
ExtremitiesExtremities
Peripheral Nervous System

3. Cranial Nerves
Twelve pairs:
2 attach to forebrain (Tel- &
Diencephalon)
10 attach to brainstem (Mes-, Met- and
Myelencephalon)
Names relate to appearance or function
Classification
Origin
Destination

4. Olfactory Nerve (CN-I)
C: Sensory
O: Olfactory Epithelium in nasal cavity
D: Olfactory bulbs (by way of cribriform plate
of ethmoid)
Only CN directly attached to Cerebrum

5. Optic Nerve (CN- II)
C: Sensory
O: Retina
D: by way of optic
foramen of
sphenoid to
Diencephalon
(optic chiasma)
and to occipital
lobe

6. Oculomotor (CN III)
C: Motor
O: Mesencephalon
D: Somatic motor to superior, inferior, medial
recti and inferior oblique; visceral motor to
intrinsic eye muscles by way of superior
orbital fissure

7. Trochlear (CN IV)
C: Motor
O: Mesencephalon
D: superior oblique muscle
by way of superior
orbital fissure

8. Trochlear Nerve (N
IV)
Oculomotor (CN III)Oculomotor (CN III)
Lateral view

9. Trigeminal (CN
V)
C: Mixed
three major branches
1. Ophthalmic (sensory)
2. Maxillary (sensory)
3. Mandibular (mixed)
O: face / nuclei of pons
D: sensory nuclei in pons /
muscles of mastication

10. Abducens
(CN VI)
C: Motor
O: Pons
D: Lateral rectus eye muscle

11. Facial (CN
VII)
C: Mixed
O: sensory from taste receptors
of anterior 2/3 of tongue /
motor from pons
D: Sensory to sensory nuclei of
pons / motor muscles of facial
expression, visceral motor to
tear gland.

12. Facial (CN VII), cont’d
Bell’s Palsy

13. Vestibulocochlear (CN VIII)
• C: Sensory
• O: Receptors of inner Ear
• D: Nuclei in Pons and medulla
oblongata
• AKA acoustic nerve

14. Vestibulocochlear (CN VIII)

15. Glossopharyngeal (CN IX)
C: mixedC: mixed
O: sensory from posteriorO: sensory from posterior
1/3 of tongue / motor from1/3 of tongue / motor from
medulla oblongatamedulla oblongata
D: medulla / muscles forD: medulla / muscles for
swallowing, parotid glandswallowing, parotid gland

16. Vagus (CN X)
C: Mixed
O: Sensation from pharyngeal area and outer
ear / motor from medulla
D: Sensory to medulla / visceral
(autonomic) motor to thoracic and
abdominal cavities and their organs.
Major motor pathway for ANS
Most important Cranial Nerve!

18. Accessory (CN XI) AKA Spinal Accessory
C: Motor
O: Motor nuclei of medulla and spinal cord
D: Swallowing, Trapezius & SCM
Hypoglossal (N XII)
C: Motor
O: Motor nuclei of medulla
D: Tongue musculature

19. CN XII
CN XI

20. Spinal Nerves
• Sensory & Motor
• Through Intervertebral
Foramina
• Dermatomes

21. 4 Principal4 Principal PlexusesPlexuses
A blend, or network, of
nerve fibers from several
spinal roots.
Cervical, includes Phrenic N.
Brachial
Lumbar
Sacral

22. Cervical PlexusCervical Plexus
PhrenicPhrenic
nervenerve --
innervatesinnervates
diaphragmdiaphragm

23. Brachial PlexusBrachial Plexus

24. Nerves of Arm
Musculocutaneous
nerve – innervates biceps
and brachialis muscles
Median nerve -
innervates lateral flexors
Ulnar nerve - innervates
medial flexors
Radial nerve -
innervates forearm
extensors

25. Lumbar Plexus
Femoral Nerve
Lumbosacral
Trunk (to
Sciatic Nerve)
Obturator
Nerve

26. SacralSacral
PlexusPlexus

27. Nerves of the LegNerves of the Leg
•Sciatic N.Sciatic N.
•Thickest and LongestThickest and Longest
•Branches to Tibial andBranches to Tibial and
Fibular NervesFibular Nerves
•Femoral N.Femoral N.
•Posterior aspect of legPosterior aspect of leg

28. Narrow lumbar diskNarrow lumbar disk
spaces result inspaces result in
pressure on spinalpressure on spinal
rootsroots
L-5
T-12

29. The white oval
is a
postsurgical
cyst or
abscess

30. Shingles
• Varicella-zoster virusVaricella-zoster virus ( of herpes
family)
• In dorsal root ganglia & cranial nerves
• Initial infection: chicken pox