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Biomechanics
Devoght
139
Anatomy
Graduate
10/19/2011

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Cards

Term
What is a biomechanical function of the curvatures in the spine?
Definition
to absorb shock (dissipates sharp spinal loads)
Term
What biomechanically significant difference is there between zygapophysial joints of different levels of the cervical spine?
Definition
The angle of the articular surfaces become steeper for the lower ones, limiting the amount of rotation that is possible.
Term
What is the name of the joint that is sometimes formed between an uncinate process of one vertebra and the inferior edge of the body of the vertebra above?
Definition
joint of Von Luschka
Term
What is the biomechanical significance of the compact bone of the vertebral body being continuous with the conpact bone of the pedicles?
Definition
allows loads on the anterior column (vertebral bodies) to be transferred to the posterior columns (articular pillars)
Term
What is the term that indicates that two types of motion are forced to occur simultaneously because of the geometric shape of the articular surfaces?
Definition
coupled motion_
(i.e. atlas rising up, axial translation, as it rotates on axis because of the angle of the facet surfaces
Term
The vertebral artery passes up through the transverse foramen of which cervical vertebrae?
Definition
C6 up through C1
Term
The normal range of motion consists of what two zones?
Definition
neutral zone and elastic zone
Term
What is the difference between the neutal zone and the elastic zone?
Definition
In the neutral zone the collagen fibers of the supporting structures (like ligaments) are lax and offer very little resistance to movement.In the elastic zone, the collagen fibers are taut and are stretched (giving significant resistance) as more movement occurs.
Term
How many degrees of freedom are there for an object that is not restrained in any way?
Definition
6 (3 translational and 3 rotational)_
That means it takes 3 numbers to specify the location of an object in 3 dimensional space and_
3 more numbers to specify how it is oriented at that position.
Term
If a 3-D Cartesian coordinate system is oriented in the standard way on a vertebral body, which way is the positive X axis? the positive Y axis? the positive Z axis?
Definition
positive X: out to the left_
positive Y: caudal to cephalic_
positive Z: posterior to anterior
Term
In a 3-D Cartesian coordinate system in standard orientation, which two axes define a frontal plane?
Definition
X and Y
Term
In a 3-D Cartesian coordinate system in standard orientation, which two axes define a transverse plane?
Definition
X and Z
Term
What cervical joint allows the most rotation? flexion/extension?
Definition
C1/C2 and occiput/C1
Term
In regards to attempting to move an object resting on a surface, how is the coefficient of friction defined?
Definition
the amount of tangential force required to move the object divided by the amount of normal (perpendicular) force pushing the object down on the surface
Term
What kind of fluid has the same viscosity no matter how much shear force is applied to it?
Definition
Newtonian (like water)
Term
What kind of fluid has increased viscosity when shear force is applied to it?
Definition
dilatant (like Silly Putty)
Term
What kind of fluid has decreased viscosity when shear force is applied to it?
Definition
thixotropic (like ketchup)
Term
Relative to how the viscosity of a fluid varies according to how much shear stress is applied to it, what kind of fluid is synovial fluid?
Definition
thixotropic
Term
When looking a stress/strain plots of biomaterials, what is the toe region?
Definition
The region of considerable strain for little increase in stress at the beginning of the curve._
(meaning it doesn't resist very much at all when you first start stretching it)
Term
Does the stress/strain plot of ligaments or tendons have a longer toe region?_
What it is about the anatomy of the structure that causes it to have longer toe region?
Definition
ligaments_
the collagen fibers are not as well lined up in ligaments, so it takes more stretching before the tensile strength of those fibers comes to bear.
Term
What is the biomechanical significance of ligaments providing less resistance when they are first starting to be stretched as opposed to tendons?
Definition
Since ligaments attach rigid bone to bone, and are lax until the joint reaches the end of the range of motion, if they didn't give a little at first there would be quite a jerk when the joint arrives there suddenly._
(that would make the attachment sites of the ligaments more susceptible to avulsion fractures)
Term
What possible explation does our author give for why the severity of an accident doesn't always correlate very well with the severity of the symptoms that result from it?
Definition
He proposes that at least one significant factor could be the exact position of the person at the time of the accident.
Term
What symptoms are often associated with occipitalization (fusion of C1 to occiput)?
Definition
ataxia, numbness with pain in limbs, hyper-reflexia and spasticity, neurological symptoms similar to MS (often misdiagnosed as MS)
Term
What is the Arnold-Chirari malformation?
Definition
displacement of cerebellar tonsils down through the foramen magna into the upper part of the cervical spinal canal
Term
What symptoms are commonly associated with an Arnold-Chirari malformation?
Definition
headaches and neck pain (often brought on by a sneeze or cough)
vertigo_
syncope (temporary loss of consciousness due to reduced cerebral blood flow)
Term
What is the Kippel-Feil syndrome?
Definition
congenital fusion of 2 or more cervical vertebrae_
(no really distinctive symptoms)
Term
What is the most common pathological condition associated with a degenerative spine?
Definition
degenerative joint disease (DJD)
Term
Is it overuse or lack of use that can lead to degeneration of the spine?
Definition
either one can do so
Term
How much spinal manipulation is appropriate for a spine with anomalies or traumatic injuries?
Definition
That depends on who you talk to. There is no hard and fast set of rules to determine just how much adjusting is appropriate, especially in those kinds of cases.
Term
Concerning clincial instability, how do White and Panjabi define incapacitating pain?
Definition
Pain that is unable to be controlled by non-narcotic drugs
Term
What role do muscles play in providing spinal stability?
Definition
A small role - limited to the acute phase of injury.
Term
How does the spinal cord respond to changes in the length of the spine due to flexion and extension?
Definition
By stretching or contracting - not by sliding
Term
How is stability of the ocicpital-atlantal joint maintained?
Definition
By the geometry of the articulating surfaces as well as soft tissue structures.
Term
What anatomical structure has been compromised in order to allow bilateral anterior translatory displacement of of C1 relative to C2?
Definition
dens (odontoid) or transverse ligament
Term
On an A-P open mouth x-ray, what is indicated by a combined left and right overhang of C1 on C2 by 7 mm or more?
Definition
Jefferson fracture (C1) and probably rupture of transverse ligament
Term
What anatomical structure has been compromised in order to allow bilateral posterior translatory displacement of of C1 relative to C2?
Definition
dens (odontoid)
Term
What anatomical structures have probably been compromised in order to allow unilateral anterior rotatory displacement of of C1 relative to C2?
Definition
damaged or abnormal odontoid, damaged transverse ligament, and disruption of the articular capsule on the side of the rotation
Term
36. What anatomical structures have probably been compromised in order to allow unilateral posterior rotatory displacement of of C1 relative to C2?
Definition
damaged or abnormal odontoid and disruption of the articular capsule on the side of the rotation
Term
What anatomical structures have probably been compromised in order to allow unilateral combined anterior and posterior rotatory displacement of of C1 relative to C2?
Definition
bilarteral articular capsule disruption
Term
What is the V sign?
Definition
Tilting of C1 relative to the dens._
(may be normal variant and not indicate clinical instability)
Term
In what position will a patient be unstable if anterior ligaments have been compromised?
Definition
extension_
(in flextion if the posterior elements have been compromised)
Term
What biomechanical factor adds to the instability of a wedge shaped cervical or thoracic vertebral body fracture?
Definition
The cephalic portion of the body will be abnormally forward, thereby resulting in an increased moment arm, resulting in increased moments causing greater stresses.
Term
What are the 4 progressive elements of Palmer's idea of the subluxation?
Definition
1. vertebral misalignment_
2. narrowing of the IVF_
3. nerve pressure_
4. interference with nerve function
Term
What term is used by practitioners of manual medicine that refers to some sort of disturbance of internal function of a vertebral unit?
Definition
segmental dysfunction
Term
Myotendious:
Definition
Altered muscle tone accompanied by painful response to pressure.
Term
What term applies to a noninflammatory degenerative condition located within the muscle belly?
Definition
myosis
Term
What term applies to abnormalities affecting the myotendinous junction?
Definition
attachment tendinosis
Term
A four step reverberating cycle has been proposed to explain how a segmental dysfunction can be perpetuated. According to that model, how is the cycle broken?
Definition
Sudden overstretching of muscle spindles.
Term
What term is commonly used by osteopaths to refer to what they think of as a manipulable lesion?
Definition
somatic dysfunction
Term
What term refers to 2 adjacent vertebrae and the connecting soft tissue?
Definition
functional spinal unit (FSU)
Term
Functional Spinal Region (FSR):
Definition
Multiple FSU's functionally connected to accomplish a specific task._
(a particular vertebra could be a part of several different FSR's)
Term
Which cervical articulation has the most flexion/extension? rotation?
Definition
C0/C1 C1/C2
Term
What term refers to structual homeostasis, consisting of proper transfer of loads throughout the body?
Definition
mechanical equilibrium
Term
In regards to the various structures of the spine, what is meant by the term mechanical failure?
Definition
Excessive deformation (impairing function) or_
Loss of continuity
Term
dynamic analysis:
Definition
Considers the changing positions and the inertia of the parts involved_
(moving segments tend to keep on moving, or stationary ones tend to stay stationary)
Term
quasistatic analysis:
Definition
Considers the changing geometry of moving parts but ignores inertial effects_
(assumes that movement occurs slow enough that inertia is negligible)
Term
What two zones make up the range of motion?
Definition
neutral zone and_
elastic zone
Term
Central sensitization:
Definition
Increased sensitivity of spinal cord neurons to pain which may be caused by prolonged painful stimulus.
Term
According to Triano (author of Herzog's Chapter 4), what 4 factors moderate the location and extent of injury?
Definition
1. injury load_
2. posture_
3. muscular tension_
4. tissue status
Term
hysteresis:
Definition
The energy that is lost during the loading/unloading cycle of a specimen due in internal friction.
Term
On a stress/strain curve, where is the ultimate strength?
Definition
The highest point on the plot, which is usually between the elastic limit and the fracture/breaking point.
Term
dynamic creep demormity:
Definition
Reponse to rapidly repeated loading, such as the articular cartilage of the knee while walking, in which the thickness decreases with every step and then increases between steps. The overall thickness decreases over time, up to a point.
Term
According to our text, what are the two theoretic bases of aging?
Definition
1. Genetic theories_
2. Environmental theories
Term
What percentage of post menopausal women have radiological signs of osteoporotic fracture?
Definition
25 percent
Term
33. What is the average age at which menopause occurs?
Definition
51_
(can occur as early as before age 40)
Term
What two functional changes occur to articular cartilage as age increases?
1. Reduced shock absorption_
Definition
1. Reduced shock absorption_
2. Increased friction
Term
What change can be seen visually on acticulating surfaces as the person ages?
Definition
a roughening of the surface
Term
What are the three types of age related changes that occur in the nervous system?
Definition
1. Decreased sensory sensitivity_
2. Decreased reflex activity_
3. Denervation of muscle spindles
Term
What is the general concept of Occam's Razor?
Definition
The notion that is the best explantion is probably the simplest one that is able to explain all observations.
Term
mechanical buckling:
Definition
A deformation that occurs suddenly and is disproportionately large for an incremental increase of the applied load.
Term
What are the three factors that are associated with the mechanical buckling of isolated FSU's (functional spinal units) and FSR's (functional spinal regions)?
Definition
1. Single overload events (can be unguarded or guarded)_
2. Prolonged static posture_
3. Vibration (accelerates the process)
Term
42. What two questions are being attempted to be answered by doing a manual spinal evaluation?
Definition
1. Is this subject healthy or not healthy?_
2. If not healthy, what is the level of the lesion?
Term
What two objective measurements have been shown to be different for healthy groups than for low back pain groups?
Definition
1. LBP group has decreased ROM_
2. LBP group has increased sensitivity to pressure on both the spinous processes and paraspinal muscles.
Term
What are 4 feasible mechanisms for injury to practicing chiropractors?
Definition
1. Repetitive motion_
2. Sudden loading of cervical spine during delivery of thrusts_
3. Prolonged postures in lumbar flexion_
4. Sudden overloads during patient prep
Term
What are 3 things you can do to reduce the risk of injury to your self during patient transfer?
Definition
1. Shift the center of your body mass down and posterior_
2. Maintain erect posture_
3. Use auxiliary support, such as bracing your knee against the table
Term
What positional risk is associated with the delivery of a toggle recoil type
Definition
Your wrist is already in maximum radial deviation and you are thrusting into it further.
Term
What positional risk is associated with the delivery of a toggle recoil type
Definition
Your wrist is already in maximum radial deviation and you are thrusting into it further.
Term
According to Triano, what is the most stable wrist position for adjusting?
Definition
Slight unlnar deviation and flexion
Term
Natural frequency:
Definition
The frequency at which an object tends to vibrate.
Term
Resonance:
Definition
The large response of an object to a periodic (cyclic) driving force that oscillates at that object's natural frequency.
Term
What are the 4 notable aspects of load-time histories (or force/time profiles)?
Definition
1. Preload_
2. Peak load_
3. Duration of the impulse_
4. Rate of rise of the applied load
Term
What is the most common side effect (risk) associated with chiropractic care?
Definition
mild soreness (not mild pain)
Term
If mild soreness does occur in response to an adjustment, how soon does it typically appear and long does it typically remain?
Definition
Typically appears within 4 hours and disappears within 24 hours.
Term
What proportion of chiropractic patients report have experienced mild soreness after an adjustment at least once?
Definition
about half
Term
s there evidence to suggest that it is risky to adjust vertebral segments demonstrating excessive motion with internal disc disruption?
Definition
No
Term
arthodesis:
Definition
Surgical fusion of a joint.
Term
How long does it typically take for a surgically induced fusion to become solid?
Definition
Usually 3 to 6 months._
(don't adjust that area until the fusion is solid)
Term
What problem can occur that affects the stability of a metal implant in the spine?
Definition
bone resorption around the implant that weakens its grip
Term
What are patient-based factors that can be used as control elements for spinal manipulation?
Definition
Static and dynamic posturing of the patient.
Term
What are provider-based factors that can be used as control elements for spinal manipulation?
Definition
Preload amplitude_
Load direction_
Load peak amplitude_
Load impulse rate_
Load duration
Term
What is the primary motion that occurs during spinal manipulation?
Definition
rotation (translation is negligible)
Term
What normally determines the location of the axis of rotation for the rotational movement in response to a spinal manipulation?
Definition
geometry of the facet surfaces
Term
What 3 components sum up to compose the load that is actually transmitted to the segment being adjusted?
Definition
1. Applied load_
2. Body segment inertial loads_
3. Muscle tension
Term
What can be said about the timing of muscular response to a spinal manipulation?
Definition
The muscles can respond fast enough to affect the process of an HVLA type adjustment.
Term
How does the preload affect the stiffness of the soft tissue comopnents of the FSU (functional spinal unit)?
Definition
Increases stiffness as a whole by engaging the elastic properties.
Term
How does the stiffness of the spine vary in response to the quickness of the treatment given?
Definition
The quicker the treatment, the greater the stiffness of the spine.
Term
What is the objective of properly postioning a patient for a particular adjustmentt?
Definition
To maxmize the biomechanical effect of the adjustive thrust.
Term
What 5 methods of unloading spinal elements were discussed in class?
Definition
1. Aquatherapy_
2. Continuous passive motion (CPM)_
3. Flexion-distraction_
4. Non-linear axial traction (VAX-D)_
5. Treadmill (or chair) with axial traction
Term
What are two common situations that often result in pain from facet joints?
Definition
1. DJD (degenerative joint disease)_
2. Pregnancy
Term
What is Triano's thinking in regards with adjusting patients with spinal implants, like Harrington rods?
Definition
You need to be careful, but these patients do seem to benefit normal chiropractic care.
Term
What are the 5 cardinal signs of inflammation?
Definition
1. rubor - redness_
2. tumor - swelling_
3. calor - heat, or fever_
4. dolor - pain_
5. functio laesa - loss of function
Term
What are two benefits of inflammation?
Definition
maintenance of tissues_
allows for remodeling
Term
What are the two fairly distinct forms of inflammation?
Definition
acute and chronic
Term
What are the three phases of acute inflammation?
Definition
1. vasodilation_
2. slowing of blood flow_
3. migration of white blood cells
Term
What are three characteristics of chronic inflammation?
Definition
1. accumulation of lymphocytes and macrophages_
2. angiogenesis_
3. connective tissue proliferation
Term
What are three modalities that chiropractors can use for the management of inflammation?
Definition
1. ice_
2. nutrition_
3. exercise strategies
Term
According to what hypothesis is the most common spinal lesion recognized by:_
Definition
1. lessened or otherwise altered mobility_
2. altered pressure threshold to pain and_
3. signs of neuromuscular dysfunction?
segmental dysfunction hypothesis
Term
What is segmental facilitation?
Definition
A lowered threshold for firing a neuron in the spinal cord as a result of afferent bombardment associated with spinal lesions.
Term
As extrafusal muscle fibers contract, how is proper tension maintained in the intrafusal muscle fibers of muscle spindles?
Definition
The afferent fibers of the spindle sense that the intrafusal muscle fibers are lax and send that info the CNS._
The CNS then sends down instructions via the efferent fibers of the spindle to adjust the tension accordingly.
Term
According to Jones, what happens in response to the increased joint capsule tension caused by an entrapped joint meniscoid?
Definition
Mechanoreceptor activity increases, which leads to_
increased nociception, which leads to_
decreased pain threshold and hypertonic paraspinal musculature
Term
According to Jones, what can happen as a result of the sustained joint hypomobility associated with an entrapped joint meniscoid?
Definition
capsular adhesions can develop which can eventually lead to_
obliteration of the joint space.
Term
What aspects of the subluxation are specifically targeted with Henderson's rat model?
Definition
fixation and mal-position
Term
ccording to the Korr Model of Segmental Dysfunction, how does the CNS get confused about where a body segment is?
Definition
The muscle spindles send inaccurate proprioceptive info to the CNS. They got mis-set because while you are in the process of moving to a new position, you were bumped externally. That caused you to move farther than the CNS told your muscles to move you. Consequently, the muscle spindles got set for a position the CNS thought you were in - not the position you ended up actually being in.
Term
According to the Patterson-Steinmetz model, how was "spinal learning" demonstrated to have occurred in rats?
Definition
If the spinal cord was severed right away, communication was blocked between the lesion and the hind leg, and the hind leg relaxed._
If more than 45 minutes passed between inducing the lesion and cutting the cord, the leg stayed flexed, even though there was no communication between where the lesion was and the leg itself._
Therefore, it was assumed that during the time between when the lesion was induced in the brain and when the cord was cut, something happened in the spinal cord below where it was severed to cause it to "learn" that the leg was supposed to stay flexed.
Term
What is the general notion of the Mense Model?
Definition
there is some sort of self-reinforcing cycle by which a spasm results in localized ischemia and edema which induces the release of vasoneuroactive substances that reinforce the spasm.
Term
What is the general notion of the instability hypothesis?
Definition
Damage to supporting tissues allows excessive motion and instability that can cause abnormal stress distribution resulting in conditions that predispose the spine to painful episodes.
Term
What are the 4 methods described in class for quantifying the degree of cervial curvature on a lateral x-ray?
Definition
1. curve depth_
2. C2-C7 angle_
3. chord-C7 angle_
4. radii of curvature
Term
According to the neuropathology hypothesis, how can the nerve root be distorted besides from the bony compression that can result from a reduced IVF?
Definition
The nerve root could be stretched or_
it could be compressed against the IVF by inflammation of soft tissues and edema within the IVF
Term
How do dorsal roots compare to peripheral nerves in their susceptibility to compression?
Definition
Dorsal roots are much more susceptible than peripheral nerves.
Term
In what manner is a nerve fiber distorted as a result of a blockage along its course?
Definition
both radial distention and lengthening
Term
What term is used to refer to hyperactive sympathetic function associated with segmental dysfunction?
Definition
sympathicotonia
Term
if vertigo is induced by the patient laterally rotating their head back and forth, how can you determine if the vertigo is cervicogenic or vestibular?
Definition
Hold the patient's head still and have them rotate their body under the stationary head._
If vertigo is still induced, it must be cervicogenic since the vestibular apparatus was stationary._
(that is the Fitz-Ritson test)
Term
What mechanism was proposed in Leach's text to explain how chiropractic adjustments might help reduce the plasma extravasation - a major feature of acute inflammation?
Definition
Adjustments are thought to affect the plasma levels of Substance P, which acts on mast cells to initiate the release of prostaglandin (the substance that causes plasma extravasation).
Term
What is the basic concept of the myelopathy hypothesis?
Definition
That an intervertebral subluxation can cause compression or other irritation directly on the spinal cord.
Term
What is the basic contention of the dentate ligament hypothesis (as proposed by John Grostic)?
Definition
Inasmuch as the dentate ligament attaches the spinal cord to the dura mater, if the dura mater is pulled in some manner, the dentate ligaments will therefore pull on the spinal cord which can cause aberrations in function of the nerves that pass by near the attachment site of the dentate ligament.
Term
What is the basic concept of the vertebrobasilar insufficiency hypothesis?
Definition
That cervical joint misalignments can cause a kink in the vertebral arteries, thereby reducing blood flow to the brain.
Term
ccording to Seyle's General Adaption Syndrome (GAS), how does the body develop a disease of adaption as the result of continual stress of some kind?
Definition
1. When the stress is first applied, there is an alarm reaction._
2. After some time the body settles into a stage of resistance._
3. If the body is not able to sustain the stage of resistance over time, then a disease of adaption develops.
Term
According to Herzog, what are the three phases of a force/time profile of a manual chiropractic adjustment?
Definition
1. preload phase_
2. thrust phase_
3. resolution phase
Term
How long is the thrust phase of a typical force/time profile of a manual chiropractic adjustment?
Definition
100 - 200 msec
Term
What are the three types of measurable responses that are elicited by chiropractic adjustments?
Definition
1. mechanical responses_
2. neuromuscular reflex responses_
3. physiologic responses
Term
What kinds of movements of a vertebral segment are typically caused by a manual adjustment?
Definition
1. rotation in a transverse plane
2. rotation in a sagittal plane
Term
Are the neuromuscular reflex responses elicited by manual adjustments inhibitory or excitatory?
Definition
They can be either.
Term
Do all receptors affected by an adjustment typically respond at pretty much the same time relative to the force/time profile?
Definition
No. Some occur early in the profile and some occur later on.
Term
Generally speaking, how long is the delay between the beginning of the force/time profile of a manual adjustment and the EMG response to it?
Definition
typically between 50 and 200 msec
Term
How long does the EMG response to a manual adjustment usually last?
Definition
from 100 - 400 msec
Term
How does the measureable response of a manual adjustment compare to that of an instrumented (Activator-like) adjustment?
Definition
A manual adjustment usually elicits both cavitation and an EMG response._
An instrumented adjustment does not typically elicit cavitation and little or no EMG response.
Term
Are large decreases of EMG activity levels seen right after a chiropractic treatment?
Definition
Yes, but not usually.
Term
What is currently thought to be the cause of the audible release, or "crack", often heard in connection with a manual adjustment?
Definition
The formation of gas bubbles in the synovial fluid of the facet joints (cavitation) or_
Possibly the snapping of the capsular ligment that occurs as the joint is rapidly stretched out.
Term
f a chiropractic does not perceive an audible release when delivering a manual adjustment, a second thrust is often made. In that case, how does the second thrust compare to the first?
Definition
The second thrust usually has a higher peak force and_
a higher rate of force application._
An audible release is often heard in connection with the second thrust.
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