Cranial/Spinal Nerves

  1. Olfactory Nerve
    • Cranial Nerve I
    • Origin:  olfactory epithelium
    • Purely sensory
    • Function:  sense of smell
    • Clinical Symptoms:  partial/total loss of smell
    • Testing:  Asked to sniff different aromas
  2. Optic Nerve
    • Cranial Nerve II
    • Origin:  Retina
    • Purely sensory
    • Function:  vision
    • Clinical Symptoms:  partial/total blindness
    • Testing:  eye chart, first see object, ophthalmoscope
  3. Oculomotor Nerve
    • Cranial Nerve III
    • Origin:  Brainstem
    • Mixed function
    • Somatic/parasympathetic motor to iris & ciliary muscle for focus.
    • Function:  move the eye and eyelid, pupil constriction, lens shape
    • Clinical Symptoms:  eye cannot move, at rest rotates laterally, eyelid droop, double vision
    • Testing:  Size, shape, equality, reflex of pupil
  4. Trochlear Nerve
    • Cranial Nerve IV
    • Origin:  Brainstem
    • Mixed function
    • Function:  Moves eye muscle (superior oblique)
    • Clinical symptoms:  Double vision, problems rotating eye inferolaterally
    • Testing:  Size, shape, equality, reflex of pupil
  5. Trigeminal Nerves
    • Cranial Nerve V
    • Origin:  Brainstem
    • Mixed function
    • Ophthalmic Function:  Sensory from skin of upper face
    • Ophthalmic Testing:  Corneal reflex
    • Maxillary Function:  Sensory from skin of lower face
    • Maxillary Testing:  Safety pin, hot and cold objects
    • Mandibular Function:  motor fibers for chewing, sensory from face
    • Mandibular Testing:  clench teeth, move jaw
    • Clinical Symptoms All:  Stabbing pain to face
  6. Abducens Nerve
    • Cranial Nerve VI
    • Origin:  Brainstem
    • Mixed Function
    • Function:  Motor fibers to eye muscle (lateral rectus), proprioceptors from same muscle to brain
    • Clinical Symptoms:  Eye cannot move laterally, at rest moves medially
    • Testing:  Pupil testing
  7. Facial Nerves
    • Cranial Nerve VII
    • Origin:  Brainstem
    • Mixed Function
    • Somatic/Parasympathetic Motor:  Lacrimal and salivary glands
    • Function:  Facial expression, proprioceptor to pons, taste buds anterior 2/3 of the tongue
    • Clinical Symptoms:  Bell's palsy, paralysis of facial muscles on affected side
    • Testing:  taste buds tested, symmetry of face checked
  8. Vestibulocochlear Nerve
    • Cranial Nerve VIII
    • Origin:  Inner ear
    • Mostly Sensory
    • Function:  Equilibrium, hearing
    • Clinical Symptoms:  Deafness, dizziness, REM, loss of balance
    • Testing:  Hearing is checked
  9. Glossopharyngeal Nerve
    • Cranial Nerve IX
    • Origin:  Brainstem
    • Mixed Function
    • Somatic/Parasympathetic Motor:  Salivary
    • Function:  Tongue & pharynx, taste and touch from posterior 1/3 tongue,
    • Clinical Symptoms:  Impairment of swallow/taste
    • Testing:  Gag/swallow reflex, speak/cough
  10. Vagus Nerve
    • Cranial Nerve X
    • Origin:  Brainstem
    • Mixed function
    • Somatic/Parasympathetic Motor:  Vagus, ventral body cavity
    • Function:  Motor to pharynx/larynx (swallowing); parasympathetics to ventral body cavity
    • Clinical Symptoms:  Loss of voice, difficulty swallowing, impaired digestive system
    • Testing:  Gag/swallow reflex, speak/cough
  11. Accessory Nerves
    • Cranial Nerve XI
    • Origin: Brainstem
    • Mixed Function
    • Function:  Joins with Vagus, spinal root moves head/neck, conveys proprioceptors
    • Clinical Symptoms:  Head turned toward injury side, difficulty shrugging shoulder
    • Testing:  Head rotation and shoulder shrug
  12. Hypoglossal Nerves
    • Cranial Nerve XII
    • Origin:  Brainstem
    • Mixed function
    • Function:  Muscles of tongue,
    • Clinical Symptoms:  Difficulties in speech and swallowing
    • Testing:  Protrude and retract tongue
  13. How many spinal nerves
    31 pairs
  14. What are the types and number of spinal nerves
    • 8 cervical
    • 12 thoracic
    • 5 lumbar
    • 5 sacral
    • 1 coccygeal
  15. Are spinal nerves sensory, motor or mixed?
    All are mixed
  16. Which nerves are segmental?
    • All dorsal rami
    • Ventral rami from T2 to T12
  17. Which nerves form plexi
    All cervical, lumbar, sacral, coccygeal and T1 of thoracic
  18. What are the innervation patterns for the dorsal rami?
    Innervates the posterior trunk in a narrow strip in line with the exit site, segmental fashion.
  19. What are the innervation patterns for the ventral rami?
    Innervates the ventral region of the trunk (segmental fashion to the intercostals: ribs & branches to the skin) and the limbs (plexi)
  20. What are the names of the different plexi?
    • Cervical (C1-C5)
    • Brachial (C5-T1)
    • Lumbar (L1-L4)
    • Sacral (L4-S4)
  21. Phrenic Nerve
    • Cervical plexus
    • Motor/sensory of the diaphragm
    • C3, C4, C5
  22. Axillary Nerve
    • Brachial plexus
    • Shoulder joint and deltoid
  23. Musculocutaneous Nerve
    • Brachial plexus
    • biceps brachii, brachialis, sensory lateral forearm
  24. Median Nerve
    • Brachial plexus
    • forearm flexors, palm
    • Carpal tunnel syndrome
  25. Ulnar Nerve
    • Brachial plexus
    • Medial forearm and hand
    • Funny bone
  26. Radial Nerve
    • Brachial plexus
    • Posterior arm to hand: extensors
  27. Femoral Nerve
    • Lumbar plexus
    • Anterior thigh muscles
    • Mostly anteromedial skin of leg
    • Gait problem if herniated disc in region
  28. Sciatic Nerve
    • Sacral plexus
    • Posterior thigh, leg and foot
    • Thickest/longest in the body
  29. Nerve Regeneration in the PNS
    • Nerves can regenerate if cell body is unharmed
    • Further away from the cell body the more successful the regeneration
    • Difference from CNS:  Schwann cells promote regeneration, CNS glial cells inhibit
    • 1.  Fragmentation of the axon at the injury site.
    • 2.  Macrophages destroy the axon distal to the injury.
    • 3.  Axon filaments grow within a regeneration tube formed by Schwann cells.
    • 4.  Regenerated axon and the formation of a new myelin sheath
  30. Dermatome
    • The area of skin innervated by the cutaneous branches of a single spinal nerve
    • Mapping of skin area or sensory field carried/represented in a single dorsal root
  31. Reflex
    • Rapid movement that occurs automatically, with no conscious effort
    • Inborn/intrinsic
    • Learned/conditioned
  32. Inborn/intrinsic Reflex
    • Visceral - at the level of the organs
    • Does not require cerebrum
    • Usually protective
    • Spinal/brainstem reflexes
    • Rapid/predictable response
    • Somatic
  33. Learned/Conditioned Reflex
    • Requires cerebrum
    • Becomes a reflex with practice
    • i.e. foot on the brake
  34. Basic components of a reflex
    • Receptor
    • Sensory neuron
    • Integration center
    • Motor neuron
    • Effector
  35. Similarities of visceral/somatic reflex arcs
    • Start at receptors
    • Integration center (CNS)
    • Dorsal root first to spinal cord
    • Exit to receptor
  36. Differences of visceral/somatic reflex arcs
    • Outflow
    • Where they start
    • Number of neurons in the pathway
  37. How does referred pain relate to somatic/visceral reflexes
    • Pain from viscera perceived as somatic in origin
    • Visceral pain afferents travel with somatic nerves
    • Confuses CNS in the spinal cord
  38. Monosynaptic reflex
    • 1 synapse in the CNS
    • Ipsilateral
    • Direct to motor neuron
    • Patellar reflex
  39. Polysynaptic reflex
    • More than 1 synapse
    • Involves interneurons inhibiting on antagonistic
    • Component of stretch reflex is reciprocal inhibition
    • Stepping - need the other foot down to lift the first foot
    • Opposite sides of the spinal cord
  40. Which nerves are purely sensory
    • Cranial nerves I and II and VIII is mostly sensory
    • Olfactory, optic and vestibulocochlear
  41. Which cranial nerves do not originate from the brainstem and where are their origins
    • Cranial nerve I, olfactory from olfactory epithelium
    • Cranial nerve II, optic from retina
    • Cranial nerve VIII, vestibulocochlear from inner ear
  42. Which cranial nerves carry parasympathetics
    • Cranial nerve III, oculomotor, ciliary muscle and iris of the eye
    • Cranial nerve VII, facial, salivary and lacrimal glands
    • Cranial nerve IX, glossopharyngeal, salivary
    • Cranial nerve X, vagus, ventral body cavity
Card Set
Cranial/Spinal Nerves
A&P 2, cranial and spinal nerves