Chapter 10 Flashcards
What are the forces acting on the spine as mentioned in Lecture 10?
Body weight, tension in the spinal muscles, tension in surrounding muscles, intra-abdominal pressure, and any external loads.
What is termed as ‘axial’ loading on the spine?
Loading when in an upright position.
How does spinal compression increase with body positions?
Spinal compression increases from lying supine to standing upright, sitting erect, standing leaning forwards, and sitting slouched.
What is the direction of disc displacement when standing and leaning forwards?
The disc displacement direction is anterior.
What is postural sway?
The forwards & backwards movement of the spine during erect standing.
What increases compensatory tension in the back extensor muscles when carrying greater loads?
Increased External Moment Arms.
What is the primary force acting on the spine according to the scenario discussed?
The major force derived from muscle activity rather than external forces.
What is one of the effects of lateral flexion on the spine?
It increases compressive load, with specific figures being 1400N for lateral flexion and 2500N for twisting.
What happens to shear forces during rapid, jerky lifting methods?
They dramatically increase compression and shear forces on the spine.
What contributes to disk herniation according to Lecture 10?
Excessive shear forces.
What is the role of muscle tension in the lumbar region?
It is directed posteriorly, counteracting anterior-directed shear from body weight.
What does relaxation of spinal muscles at full flexion provide?
Support for the spine comes exclusively from the posterior spinal ligaments.
How does increased intra-abdominal pressure help the spine?
It may help to stiffen the trunk to prevent spine buckling under compressive loads.
What potentially dangerous action occurs during the Valsalva Maneuver?
Holding one’s breath when lifting can constrict carotid arteries and blood supply to the brain.
What posture is recommended when lifting according to body mechanics?
Lift with the legs and maintain a normal lumbar curve.
What characterizes mechanical spinal instability?
A predisposition to failure when loading demands are reduced, including high loads and motor error.
What factors define desirable spinal stability during lifting?
Minimizing trunk flexion to reduce torque on the spine.
How long do smartphone users spend hunched over per day?
An average of two to four hours.
How do muscle spindles respond to muscle stretching?
They respond to slow, slight stretching of the muscle.
What statement reflects the misconception during increased neck flexion?
The quote that the weight on the cervical spine increases as it bends forward is incorrect.
What is the effect of increasing angles of neck flexion on muscle force?
The muscle force increases progressively: 27 lbs at 15 degrees, 40 lbs at 30 degrees, 49 lbs at 45 degrees, and 60 lbs at 60 degrees.
How do the rotatores contribute to spine function?
They create axial twisting torque.
What challenges the role of intertransversarii in lateral flexion?
Their small physiological cross-sectional area limits the amount of twisting and bending torque they can generate.
What are the primary forces acting on the spine?
Body weight, tension in the spinal muscles, tension in surrounding muscles, intra-abdominal pressure, and any external loads.
What position during loading is referred to as axial?
In an upright position.
How does spinal compression increase during different positions?
Spinal compression increases from lying supine to standing upright, sitting erect, standing leaning forwards, and sitting slouched.
What is meant by postural sway?
The forwards and backwards movement of the spine during erect standing.
What counters the constant forward bending moment in the spine?
Tension in the back extensor muscles.
What increases compensatory tension in the back extensor muscles?
Greater loads and increased external moment arms.
What is the major force acting on the spine?
Usually that derived from muscle activity rather than external forces.
What are the typical values for normal torque, extension torque, and lateral flexion & twisting torque on the spine?
Normal torque is 50 Nm, extension torque is 800 N of compression, lateral flexion is 1400 N and twisting is 2500 N of compression.
What occurs during Valsalva maneuver?
Increasing intra-thoracic pressure against a closed glottis.
What is the potential danger of holding one’s breath when lifting?
It can constrict the carotid arteries, limiting blood supply to the brain.
How does muscle tension in the lumbar region act relative to shear forces on the spine?
Muscle tension in the lumbar region is directed posteriorly, partially counteracting anterior-directed shear from body weight.
What are the effects of intra-abdominal pressure on the spine?
It may help to stiffen the trunk to prevent spine buckling under compressive loads.
What is the significance of maintaining a normal lumbar curve while lifting?
It minimizes trunk flexion, thereby reducing torque on the spine.
What is mechanical spinal instability?
A predisposition to failure when loading demands are reduced due to high loads imposed on the spine or motor error in inter-segmental muscles.
What are the effects of smartphone usage on neck position?
Smartphone users can spend an average of two to four hours per day hunched over, leading to poor neck posture.
What does the arrangement of cancellous bone in vertebrae allow?
It allows the vertebral body to act as a shock-absorbing system.
What role do the Rotatores and Intertransversarii muscles serve in the spine?
They are involved in creating axial twisting torque and lateral flexion, respectively.
How do muscle spindles in the spine respond to stretching?
They respond to slow, slight stretching of the muscle, and a faster rate of stretching provokes a stronger response.
What is the impact of jerky lifting movements on the spine?
It dramatically increases compression and shear forces on the spine.
What is recommended to avoid lumbar flexion during exercises?
Using exercises like the cat-cow and side plank, which maintain the spine in a neutral position.
What is meant by the ‘guy wire’ design of spinal muscles?
It provides mechanical ability to stabilize the spinal segment.
What is the consequence of excessive shear forces on the spine?
Excessive shear is believed to contribute to disk herniation.
What are the forces acting on the spine as mentioned in Lecture 10?
Body weight, tension in the spinal muscles, tension in surrounding muscles, intra-abdominal pressure, and any external loads.
What is termed as ‘axial’ loading on the spine?
Loading when in an upright position.
How does spinal compression increase with body positions?
Spinal compression increases from lying supine to standing upright, sitting erect, standing leaning forwards, and sitting slouched.
What is the direction of disc displacement when standing and leaning forwards?
The disc displacement direction is anterior.
What is postural sway?
The forwards & backwards movement of the spine during erect standing.
What increases compensatory tension in the back extensor muscles when carrying greater loads?
Increased External Moment Arms.
What is the primary force acting on the spine according to the scenario discussed?
The major force derived from muscle activity rather than external forces.
What is one of the effects of lateral flexion on the spine?
It increases compressive load, with specific figures being 1400N for lateral flexion and 2500N for twisting.
What happens to shear forces during rapid, jerky lifting methods?
They dramatically increase compression and shear forces on the spine.
What contributes to disk herniation according to Lecture 10?
Excessive shear forces.
What is the role of muscle tension in the lumbar region?
It is directed posteriorly, counteracting anterior-directed shear from body weight.
What does relaxation of spinal muscles at full flexion provide?
Support for the spine comes exclusively from the posterior spinal ligaments.
How does increased intra-abdominal pressure help the spine?
It may help to stiffen the trunk to prevent spine buckling under compressive loads.
What potentially dangerous action occurs during the Valsalva Maneuver?
Holding one’s breath when lifting can constrict carotid arteries and blood supply to the brain.
What posture is recommended when lifting according to body mechanics?
Lift with the legs and maintain a normal lumbar curve.
What characterizes mechanical spinal instability?
A predisposition to failure when loading demands are reduced, including high loads and motor error.
What factors define desirable spinal stability during lifting?
Minimizing trunk flexion to reduce torque on the spine.
How long do smartphone users spend hunched over per day?
An average of two to four hours.
How do muscle spindles respond to muscle stretching?
They respond to slow, slight stretching of the muscle.
What statement reflects the misconception during increased neck flexion?
The quote that the weight on the cervical spine increases as it bends forward is incorrect.
What is the effect of increasing angles of neck flexion on muscle force?
The muscle force increases progressively: 27 lbs at 15 degrees, 40 lbs at 30 degrees, 49 lbs at 45 degrees, and 60 lbs at 60 degrees.
How do the rotatores contribute to spine function?
They create axial twisting torque.
What challenges the role of intertransversarii in lateral flexion?
Their small physiological cross-sectional area limits the amount of twisting and bending torque they can generate.
What are the primary forces acting on the spine?
Body weight, tension in the spinal muscles, tension in surrounding muscles, intra-abdominal pressure, and any external loads.
What position during loading is referred to as axial?
In an upright position.
How does spinal compression increase during different positions?
Spinal compression increases from lying supine to standing upright, sitting erect, standing leaning forwards, and sitting slouched.
What is postural sway?
The forwards and backwards movement of the spine during erect standing.
What counters the constant forward bending moment in the spine?
Tension in the back extensor muscles.
What increases compensatory tension in the back extensor muscles?
Greater loads and increased external moment arms.
What is the major force acting on the spine?
Usually that derived from muscle activity rather than external forces.
What effect does asymmetrical frontal planar loading have on the spine?
It increases both compressive and shear loads on the spine.
What happens when lifting in a rapid, jerky fashion?
It dramatically increases compression and shear forces on the spine.
What is a possible consequence of excessive shear forces on the spine?
It is believed to contribute to disk herniation.
How does muscle tension in the lumbar region affect shear forces?
It is directed posteriorly, partially counteracting the anterior-directed shear from body weight.
What does conservative treatment of disc bulging aim to eliminate?
The need for invasive back surgery.
What happens to spinal muscles at full flexion of the torso?
They experience quiescence, and support for the spine comes from the posterior spinal ligaments.
What is the role of intra-abdominal pressure in relation to the spine?
It may help to stiffen the trunk and prevent spine buckling under compressive loads.
Why is holding one’s breath when lifting considered dangerous?
It builds pressure, constricting the carotid arteries and potentially reducing blood supply to the brain.
What is recommended for maintaining a normal lumbar curve during lifting?
Lift with the legs and avoid excessive trunk flexion.
What is referred to as ‘text neck’?
A posture associated with prolonged phone use that can negatively impact the spine.
What does increased forward flexion do to the head’s weight on the cervical spine?
It increases the weight on the cervical spine as the center of gravity shifts forward.
What is the relationship between neck flexion angles and muscle tension?
At higher angles of flexion, muscle force increases substantially, e.g., 60 lbs at 60 degrees.
How much time might smartphone users spend hunched over in a year?
700 to 1,400 hours per year, with high-schoolers potentially spending an additional 5,000 hours.
What do the rotatores muscles primarily assist with?
Creating axial twisting torque.
How do intertransversarii muscles contribute to spinal function?
Assigned to assist with lateral flexion.
What is the significance of muscle spindles in small spinal muscles?
They are highly rich in muscle spindles, responding to slow stretching rather than generating significant torque.
What can be said about the response of rotators and intertransversarii during isometric contractions?
There is no major response during isometric contractions.
What are the forces acting on the spine?
Body weight, tension in the spinal muscles, tension in surrounding muscles, intra-abdominal pressure, any external loads.
What is the effect of body position on spinal loading?
In an upright position, the loading is termed ‘axial’.
How does spinal compression increase with body position?
Spinal compression increases with lying supine, standing upright, sitting erect, standing leaning forwards, sitting slouched.
What is meant by postural sway?
The forwards and backwards movement of the spine during erect standing.
What increases the compensatory tension in the back extensor muscles?
Greater loads and increased external moment arms.
What is the major force acting on the spine?
The major force is usually derived from muscle activity rather than external forces.
What are the typical values for normal torque, extension torque, and lateral flexion & twisting torque on the spine?
Normal torque is 50 Nm, extension torque is 800 N of compression, lateral flexion is 1400 N and twisting is 2500 N of compression.
What occurs during Valsalva maneuver?
Increasing intra-thoracic pressure against a closed glottis.
What is the potential danger of holding one’s breath when lifting?
It can constrict the carotid arteries, limiting blood supply to the brain.
How does muscle tension in the lumbar region act relative to shear forces on the spine?
Muscle tension in the lumbar region is directed posteriorly, partially counteracting anterior-directed shear from body weight.
What are the effects of intra-abdominal pressure on the spine?
It may help to stiffen the trunk to prevent spine buckling under compressive loads.
What is the significance of maintaining a normal lumbar curve while lifting?
It minimizes trunk flexion, thereby reducing torque on the spine.
What is mechanical spinal instability?
A predisposition to failure when loading demands are reduced due to high loads imposed on the spine or motor error in inter-segmental muscles.
What are the effects of smartphone usage on neck position?
Smartphone users can spend an average of two to four hours per day hunched over, leading to poor neck posture.
What does the arrangement of cancellous bone in vertebrae allow?
It allows the vertebral body to act as a shock-absorbing system.
What role do the Rotatores and Intertransversarii muscles serve in the spine?
They are involved in creating axial twisting torque and lateral flexion, respectively.
How do muscle spindles in the spine respond to stretching?
They respond to slow, slight stretching of the muscle, and a faster rate of stretching provokes a stronger response.
What is the impact of jerky lifting movements on the spine?
It dramatically increases compression and shear forces on the spine.
What is recommended to avoid lumbar flexion during exercises?
Using exercises like the cat-cow and side plank, which maintain the spine in a neutral position.
What is meant by the ‘guy wire’ design of spinal muscles?
It provides mechanical ability to stabilize the spinal segment.
What is the consequence of excessive shear forces on the spine?
Excessive shear is believed to contribute to disk herniation.
