Chapter 7: Understanding Pain and Its Relationship to Injury
What is Pain?
1. Pain is the ________________ reason an athlete or patient seeks treatment
2. Definition of Pain:
a. Pain is an unpleasant ___________ and _____________ experience
associated with actual or potential _______________ or described in
terms of such damage.
3. The Function of Pain
a. Pain is both good and bad
i. It serves as a warning for _____________
ii. Pain alerts a person that something is ______________
iii. Pain protects the injured part of the body through ______________
Anatomy
1. CNS (Central Nervous System): Brain and spinal cord
a. Hypothalamus
i. It is the ________________ and __________ station of the body’s
activities
b. Thalamus
i. It is the main _______________ of the brain
ii. Sensations such as _______, ______, _______, and _______ is
analyzed here
c. Cerebral Cortex
i. Determines the ______________ and ____________ of pain
ii. Initiates descending pain control mechanisms
d. Neurons
i. It is the basic functional unit of the nervous system, aka ________
e. Nerve
i. Transmits information via electrical signals from one part of the
body to another
f. Tract (Pathway)
i. Bundle of nerve fibers that carries information
1. Descending tracts – carry information away from brain
down the spinal cord (__________________)
2. Ascending tracts – transmits information up the spinal cord
to the brain (________________)
2. PNS (Peripheral Nervous System): __________ and _______________
a. Sensory Nerves:
i. These nerves transmit impulses from the periphery of the body to
the CNS
b. Somatic motor nerves:
i. These nerves transmit impulses from the CNS to the periphery of
the body
ii. They terminate in __________________
iii. Controlled ______________
c. Autonomic Motor Nerves
i. These nerves transmit impulses from the CNS to the periphery of
the body
ii. Terminate in smooth muscle, glands, organs, and cardiac muscle
iii. Controlled ________________
Physiology
1. ANS (Autonomic Nervous System)
a. Sympathetic Nervous system: __________________
i. Example: Responsible for increase HR
b. Parasympathetic Nervous system
i. Regulates rest and digest responses. Example: decreasing HR
2. SNS (Somatic Nervous System)
a. Afferent Nerve
i. __________________
ii. Enters Spinal Cord via dorsal horn
b. Efferent Nerve
i. __________________
ii. Exits Spinal Cord via ventral horn
c. Synapse
i. Junction between two nerves. Impulses can cross the synapse in
one direction only
ii. Neurotransmitters
1. Are ___________ that transmit impulses across the synapse
2. They either __________ or ____________ a response
iii. Lock and Key
1. Neurotransmitters fit into specific receptors in the dendrites
d. Stimulus
i. Action of one agent (nerve) on another (muscle) that evokes
activity in the receiving structure or agent.
ii. Noxious stimulus
1. This stimulus causes _______. It is an unhealthy and
harmful stimulus
iii. Threshold:
1. The minimal point at which a stimulus begins to produce a
_______________.
2. The single neurons respond in an all or none fashion
iv. Sub-threshold
1. Stimulus below the ____________________.
2. It does not actually evoke a response but it does cause a
change in electrical activity of the tissue
e. Response
i. A reaction that results from stimulation that exceeds thresholds
f. Summation
g.
h.
i.
j.
i. The process by which sub-threshold stimuli add together to evoke
a response
1. Temporal Summation – ___________, sub-threshold
stimuli are being repeated one after another before previous
stimulus has dissipated.
2. Spatial Summation – _____________, Sub-threshold
stimuli come from different axons and all meet
simultaneously on one cell
Facilitation
i. Enables a neural response
Inhibition
i. Restraining or repressing a neural response
Positive Feedback
i. Activity of a neuron that is returned naturally, thereby facilitating
further activity
Negative Feedback
i. Activity of a neuron that is returned through a neural network,
thereby inhibiting further activity.
Orthopedic Injury Pain
1. Figure 7.8 page 103
2. Nociception and Nociceptors
a. Nociception is the ability to _______________
i. Pain is a ______________, _____________ experience that results
from the modulation of nociception by various factors.
ii. Nociception is a event specific activity in afferent nerve pathways
which convey information about tissue damage to the brain
b. This ability to feel pain occurs in response to ______________ stimulation
i. Mechanical nociceptor:
1. Myelinated A-Delta fibers are activated by strong
mechanical displacement of the skin
ii. Polymodal nociceptors
1. Unmyelinated C-fibers are activated by several types of
stimuli, such as heat, pressure, or inflammatory chemical
mediators
iii. Nociceptors have been found in every organ and joint capsule of
the body. They are stimulated by ________________________
and by ________________________
3. Common Stimuli that cause pain
a. Mechanical Stimuli
i. Pressure put on a nerve
ii. Most frequent type of noxious stimulus seen in sports medicine
b. Thermal Stimuli
i. _________________________________
c. Chemical Stimuli
i. Chemical inflammatory mediators cause pain
ii. Most commonly known chemical is _______________
4. Types of Pain
a. Acute pain
i. Usually from an _____________ force or ____________ force
ii. It is brief and short termed
iii. It has a rapid onset and usually of high intensity
b. Chronic Pain
i. Weeks to years
c. Referred Pain
i. Is pain at a site other than the actual location of trauma
d. Radiation Pain
i. Originates from irritated nerve root and travels along that
particular nerve’s dermatome
Theories About Pain
1. The Specificity Theory of Pain
a. States that when specific nociceptors in the periphery of the body are
stimulated, the impulse is carried to the brain via nerve pathways,
resulting in pain
2. The Pattern Theory of Pain
a. It suggests that pain occurs when the rate and pattern of sensory input
________________________________
3. The Gate Control Theory of Pain
a. Gating mechanism at dorsal horn of spinal cord, which allows only
______________________________________________________
b. The gate is the _______________, which determines which impulse will
continue up or down the spinal cord to other parts of the body.
i. Large nerve fibers conduct_________, ____________ pain
ii. Small nerve fibers conduct __________, ______________ pain
c. How is pain controlled?
i. Strong sensory stimulation can control pain by closing the gait to
pain and allowing the ____________________________________
d. The inhibitory mechanism in the Substania Gelatinosa
i. The SG send ____________________________ to the T-Cell
 Always active and always providing background inhibition
ii. Large fibers stimulate the SG
 ___________________ inhibition
iii. Small fibers inhibit the SG
 ___________________the t-cells background inhibition
e. The GCT led to the development of TENS
(_________________________________________________________)
f. Three major contributions of the gate control theory
i. The dorsal horn are sited where the dynamic activities of
______________, excitation, and modulation occur
ii. Pain cannot be explained by peripheral factors alone
iii. The brain is an active system that ___________, selects, and
modulates multiple inputs
Drugs and Pain Relief
1. Drugs block pain by filling receptors so that the neurotransmitter cannot occupy
the sites; which leads _____________________________________________.
2. Morphine like substances in the body
a. Enkephalin
i. Found in brain, GI tract, and spinal cord
ii. It has a ____________________ which means it operates at the
Spinal Cord level instead of circulating the body
iii. It is thought to ___________________ by interfering with the
signal transmission to the ____________
iv. Enkephalin is released through ___________________________
1. Enkephalin then travels to the Spinal Cord and blocks the
gate, thereby blocking the __________________ from
reaching the brain
b. Endorphins
i. Exists in several forms, produced in the ___________________
ii. They circulate the body and ________________________.
iii. Inhibits pain signal transmission and decreases the chemicals in the
CNS
iv. Modalities that may release endorphins are ___________, high
intensity low frequency motor TENS, and _________________.
c. Serotonin
i. Biochemical ____________ and _____________
ii. Found in GI tract, CNS, and platelets
iii. Mediates __________________
iv. May influence pain perception with descending tract, (brain to
spinal cord), blocks signals from peripheral nociceptors
d. Dopamine
i. Neurotransmitter in the ________________________ of the brain
ii. It is very important in regulating movement
iii. It is used by the body to _____________norepinephrine and
epinephrine
iv. It affects brain processes that __________________,
________________________, and the ability to experience
pleasure and pain
e. Opioids: Endogenous opiates
i. An Opioid is a synthetic opiate, a substance that __________ and
________________________
ii. It is used to denote the body’s naturally occurring painkillers
iii. It is _________________ times stronger than morphin
iv. Effective for varying lengths of time
Postgate Pain Theories
1. Many alternate theories have been proposed as alternatives to GCT
a. The Descending Endogenous opiate theory of pain
i. It operates at the __________________
ii. It claims the spinal gate originates from the supraspinal areas that
contain opioid-secreting neurons
b. The central control trigger theory
i. Modification of the Gate Control Theory (overloads the T-Cell)
ii. Plus an additional central inhibitory mechanism via endorphins and
enkephalin
iii. This suggests there are two different mechanisms of pain control
c. The neuromatrix theory of pain
i. This theory suggests that pain is a _______________ experience
produced by characteristics patterns of nerve impulses generated
by a _______________________ in the brain
ii. The basis of this theory was determined by _____________, prior
pain experiences, ___________ and ____________ events, and
general life stress
iii. Pain is a “_________________” event resulting from
multidimensional inputs; very unique to each individual
Pain Management
1. Central Control
a. It collects and stores information related to pain and factors this into the
body’s response to noxious stimuli
b. It is suggesting that athletes should rationalize away pain of ignore it
c. Central control can greatly influence the pain response
2. Pain
a. Multidimensional
b. More than neural impulse from _________________ stimulus
c. Four dimensions of pain
i. Sensory Dimension
1. Throbbing, stabbing, sharp, stinging, aching, splitting
2. What we feel, __________________, nature of noxious
stimulation
ii. Affective Dimension
1. Emotional or __________________ response
2. Varying, anxious, or depressed owing to painful experience
3. Influences by _______________, personality, goals, and
______________________________
4. Described as tiring, sickening, frightening, cruel
iii. Evaluative Dimension
1. Conscious thought processes concerning pain stimulus
2. Subjective judgment of pain intensity based on
_________________________________
3. Described as mild, intense, excruciating
iv. Miscellaneous Dimensions
1. Combination of ____________, affective, and
____________ dimensions
2. Described as cold, numb, tight, nagging, penetrating
3. Variable Pain Response
a. It varies from _______________________
b. Affective dimension sometimes override _____________ aspects
c. Various levels of tolerance
d. Influenced by _________________
e. Pain is where the person experiences it
4. Three levels of pain control
a. Level 1
i. Ascending influence pain control
1. Gate mechanisms occurs during _________________
2. TENS, massage, and cryotherapy
b. Level 2
i. Descending influence pain control
1. Pain relief modulated by transmissions from higher brain
centers to the dorsal horn
2. Triggers _________________ release
ii. Stimulated by noxious input transmitted to brain
iii. Possible pain relief induced by something different that is
___________________________
c. Level 3
i. Beta endorphin mediated pain control
1. Prolonged stimulation of afferent nerves triggers release of
beta endorphins by the pituitary
2. Provides long-term stimulation of _____________
pathways