Guided Lecture Notes
Chapter 34: Disorders of Somatosensory Function and Pain
Learning Objective 1. Describe the four major classes of somatosensory modalities.

Identify the four major body sensations relayed by the somatosensory system.
Learning Objective 2. Describe the organization of the somatosensory system in terms
of first-, second-, and third-order neurons.

Explain how the somatosensory system is organized and describe the location and
function of first-, second-, and third-order neurons (refer to PowerPoint Slides 2,
4, 5, and Fig. 34-1).
Learning Objective 3. Define the term dermatome and state its significance in
determining the extent of sensory deficits.

Describe the cutaneous distribution of spinal nerves/dermatomes (refer to
PowerPoint Slide 3 and Figs. 34-2 and 34-3).

Discuss the purpose of dermatome maps.
Learning Objective 4. Compare and contrast the dorsal column–medial lemniscal
pathway with that of the anterolateral pathway with regard to conduction velocities and
function.

Identify the two pathways of somatosensory neurons.

Differentiate between the dorsal column–medial lemniscal pathway and the
anterolateral pathway in terms of function and conduction speed (refer to
PowerPoint Slides 9–10 and Fig. 34-4).
Learning Objective 5. Describe the sensory homunculus in the cerebral cortex.

Identify the location and function of the somatosensory cortex (refer to Fig. 34-5).

Explain how the sensory homunculus is used to reflect the density of cortical
neurons devoted to sensory neuron input in the periphery (refer to Fig. 34-6).
Learning Objective 6. Compare the tactile, thermal, and position sensory modalities in
terms of receptors, adequate stimuli, ascending pathways, and central integrative
mechanisms.

Explain what is meant by sensory modality.

Differentiate between tactile, thermal, and position sensory modalities in terms of
receptor type, effects of stimulation, ascending pathway, and conduction velocity
(refer to PowerPoint Slide 14 and Fig. 34-7).
Learning Objective 7. Describe the role of clinical examination in assessing
somatosensory function.

Discuss the importance of pain as a diagnostic tool.

Identify pathways for the transmission of pain.

Identify factors used by health care professionals to assess pain.
Learning Objective 8. Differentiate among the specificity, pattern, gate control, and
neuromatrix theories of pain.

Compare pain theories, and discuss the merits of each (refer to PowerPoint Slide
13).
Learning Objective 9. Characterize the response of nociceptors to stimuli that produce
pain.

Define nociception, and explain why nociceptors are polymodal sensory
receptors.

Describe the mechanisms of acute pain (refer to Fig. 34-8).
Learning Objective 10. Describe the function of the endogenous analgesic mechanisms
as they relate to transmission of pain information.

Identify central pathways for the modulation of pain (refer to Fig. 34-9).

Describe the location and function of the endogenous analgesia center (refer to
PowerPoint Slide 15).

Discuss how certain medications (like opioids) activate the endogenous analgesia
system.
Learning Objective 11. Compare pain threshold and pain tolerance.

Explain the difference between pain threshold and pain tolerance.
Learning Objective 12. Differentiate acute pain from chronic pain in terms of
mechanisms, manifestations, and treatment.

Classify pain according to its location, referral, or duration.

Compare acute and chronic pain with regard to cause, mechanisms, clinical
manifestations, and treatment.
Learning Objective 13. Describe the mechanisms of referred pain, and list the common
sites of referral for cardiac and other types of visceral pain.

Describe the mechanism and locations of referred pain, and explain how it is
determined by embryologic development (refer to PowerPoint Slide 16).

Identify common sites of referred pain (refer to Fig. 34-11).
Learning Objective 14. Describe three methods for assessing pain.

Describe three methods used to assess pain, and identify the most important
indicator of pain, according to the AHCPR.
Learning Objective 15. Describe proposed mechanisms of pain relief that are
nonpharmacologic.

Identify a variety of nonpharmacologic methods used to relieve pain, and discuss
the merits of their use alone or in combination with analgesics.
Learning Objective 16. State the mechanisms by which non-narcotic and narcotic
analgesics, tricyclic antidepressants, and antiseizure drugs relieve pain.

Describe the mechanism of action for aspirin, NSAIDs, acetaminophen, opioids,
and adjuvant pain medications.

Discuss surgery as an analgesic option.
Learning Objective 17. Define allodynia, hypoesthesia, hyperesthesia, paresthesias,
hyperpathia, analgesia, and hypalgesia.

Define terms used to describe alterations in pain sensitivity including allodynia,
hypoesthesia, hyperesthesia, paresthesias, hyperpathia, analgesia, and hypalgesia
(refer to PowerPoint Slide 17).
Learning Objective 18. Describe the causes, characteristics, and treatment of
neuropathic pain, trigeminal neuralgia, postherpetic neuralgia, and complex regional pain
syndrome.

Characterize neuralgia, and differentiate between trigeminal and postherpetic
neuralgia in terms of causes, clinical manifestations, and treatment (refer to
PowerPoint Slides 20–21).

Describe complex regional pain syndrome and describe its cause, pathology,
symptoms, and treatment (refer to PowerPoint Slide 22).
Learning Objective 19. Cite possible mechanisms of phantom limb pain.

Define phantom limb pain, and discuss causative theories.

Describe the characteristics and treatment of phantom limb pain.
Learning Objective 20. State the importance of distinguishing between primary and
secondary types of headache.

Discuss the incidence of headache and identify causes as primary or secondary.
Learning Objective 21. Differentiate between the frequency of occurrence and
manifestations of migraine headache, cluster headache, tension-type headache, and
headache due to temporomandibular joint pain.

Classify headache disorders according to frequency of occurrence and signs and
symptoms (refer to PowerPoint Slide 23 and Chart 34-1).

Discuss treatment options for various headache disorder classifications.
Learning Objective 22. Cite the most common cause of temporomandibular joint pain.

Identify causes of TMJ pain, characterize the pain, and discuss treatment options.
Learning Objective 23. Characterize the nonpharmacologic and pharmacologic
methods used in treatment of headache.

Compare pharmacologic and nonpharmacologic treatment of pain.
Learning Objective 24. State how the pain response may differ in children and older
adults.

Discuss the relationship between the prevalence of pain and aging, and describe
differences in pain response between children and older adults.
Learning Objective 25. Explain how pain assessment may differ in children and older
adults.

Discuss various methods that can be used to assess pain in both children and older
adults.
Learning Objective 26. Explain how pain treatment may differ in children and older
adults.

Explain how pharmacologic and nonpharmacologic treatment of pain differs
between children and older adults.