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Questions and Answers
What does biomechanics study within a living body?
What does biomechanics study within a living body?
What is the main function of the hip joint?
What is the main function of the hip joint?
Which of the following branches focuses on describing motion without regard to forces?
Which of the following branches focuses on describing motion without regard to forces?
What does the term 'arthrokinematics' refer to?
What does the term 'arthrokinematics' refer to?
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Which anatomical structures contribute to the innominate bone?
Which anatomical structures contribute to the innominate bone?
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What is the consequence of femoral dysplasia?
What is the consequence of femoral dysplasia?
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Which of the following activities may be affected by hip joint pathology?
Which of the following activities may be affected by hip joint pathology?
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What are osteokinematics primarily concerned with?
What are osteokinematics primarily concerned with?
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What is the angle of inclination of the proximal femur at birth?
What is the angle of inclination of the proximal femur at birth?
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Which statement accurately describes the pattern of change in the angle of inclination from ages 2 to 8?
Which statement accurately describes the pattern of change in the angle of inclination from ages 2 to 8?
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What is the normal adult value of the angle of inclination?
What is the normal adult value of the angle of inclination?
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Which bone contributes the least to the formation of the acetabulum?
Which bone contributes the least to the formation of the acetabulum?
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What are the two measurements that help define acetabular alignment?
What are the two measurements that help define acetabular alignment?
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What can a malformed acetabulum lead to?
What can a malformed acetabulum lead to?
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What is excessive anteversion characterized by?
What is excessive anteversion characterized by?
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What does the center-edge angle measure?
What does the center-edge angle measure?
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What is the average center edge angle in the general adult population?
What is the average center edge angle in the general adult population?
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What indicates excessive acetabular anteversion?
What indicates excessive acetabular anteversion?
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What role does the acetabular labrum play in the hip joint?
What role does the acetabular labrum play in the hip joint?
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During which phase does the hip force exceed 300% of body weight?
During which phase does the hip force exceed 300% of body weight?
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How does the acetabular notch function during high hip forces?
How does the acetabular notch function during high hip forces?
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Which factor can lead to deterioration of the hip joint structure?
Which factor can lead to deterioration of the hip joint structure?
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What occurs with an intact acetabular labrum?
What occurs with an intact acetabular labrum?
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What is the primary function of the hip's mechanical protective mechanisms?
What is the primary function of the hip's mechanical protective mechanisms?
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What is the primary reason a torn acetabular labrum has limited healing ability?
What is the primary reason a torn acetabular labrum has limited healing ability?
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In the close-packed position of the hip, what is the recommended position for maximal stretch?
In the close-packed position of the hip, what is the recommended position for maximal stretch?
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Why do individuals with capsulitis and swelling in the hip often feel most comfortable in partial flexion?
Why do individuals with capsulitis and swelling in the hip often feel most comfortable in partial flexion?
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What best describes femoral-on-pelvic hip osteokinematics?
What best describes femoral-on-pelvic hip osteokinematics?
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What is a key characteristic of the intracapsular pressure in a healthy hip?
What is a key characteristic of the intracapsular pressure in a healthy hip?
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Which lumbopelvic rhythm involves the pelvis and spine moving in the same direction?
Which lumbopelvic rhythm involves the pelvis and spine moving in the same direction?
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During normal hip motion, how does the femoral head interact with the acetabulum?
During normal hip motion, how does the femoral head interact with the acetabulum?
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Which statement about the open packed position of the hip is true?
Which statement about the open packed position of the hip is true?
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Study Notes
Introduction
- Biomechanics is the quantitative study of how forces interact within a living body.
- Kinematics is the study of motion without regard to the forces.
- Kinetics is the study of the effects of forces.
Regional Biomechanics
- The course includes anatomical and mechanical analyses of the hip, knee, ankle, shoulder, elbow, and wrist joints.
Hip Joint
- The hip joint is formed by the articulation of the femur's head with the acetabulum of the pelvis.
- Hip function supports the lower extremities and acts as a base for the pelvis and trunk.
- Hip dysfunction can cause difficulty walking, dressing, driving, lifting, and stair climbing.
Osteology
- The innominate bone forms the pelvis.
- The proximal femur exhibits abnormal growth and development, leading to femoral dysplasia.
- Two angles define the proximal femur shape: the angle of inclination and the torsional angle.
Angle of Inclination
- The angle of inclination is measured between the femoral neck and shaft in the frontal plane.
- At birth, this angle averages 165-170 degrees.
- It typically decreases by 2 degrees per year between 2-8 years of age.
- The angle stabilizes at 125 degrees in adults.
- Coxa vara is a condition with a decreased angle of inclination.
- Coxa valga is a condition with an increased angle of inclination.
Femoral Torsion
- Femoral torsion describes the shape of the femur in the horizontal plane.
- Excessive anteversion is a condition where the femur rotates inwards.
- Retroversion is a condition where the femur rotates outwards.
- Excessive anteversion can lead to in-toeing gait.
Acetabulum
- The acetabulum forms the socket of the hip joint.
- The ilium and ischium contribute 75% to the acetabulum, while the pubis contributes the remaining 25%.
- Acetabular alignment may be abnormal, affecting hip joint stability.
Center Edge Angle
- The center-edge angle (CE) is measured in the frontal plane and describes the extent to which the acetabulum covers the femoral head.
- The average CE angle in adults is 25-35 degrees.
Acetabular Anteversion Angle
- The acetabular anteversion angle is measured in the horizontal plane and describes the extent to which the acetabulum covers the anterior aspect of the femoral head.
- An excessive angle of more than 20 degrees can increase the risk of anterior hip dislocation or subluxation.
- A retroverted angle of less than 20 degrees is also abnormal.
Arthrology
- The hip joint is a ball-and-socket joint secured by connective tissues and muscles.
- Articular cartilage and cancellous bone protect the joint.
Anatomic Features
- The femoral head includes the fovea capitis (fovea), ligamentum teres, and articular cartilage.
- The acetabulum includes the acetabular notch, lunate surface, acetabular fossa, labrum, and transverse acetabular ligament.
Joint Compressive Force
- Hip forces fluctuate during walking.
- Forces are highest during the stance phase.
- The lunate surface deforms to increase contact area and reduce peak pressure.
Acetabular Labrum
- The acetabular labrum is a fibrocartilage rim around the acetabulum.
- It helps maintain intra-articular pressure, contributing to joint stability.
- It prevents leakage of synovial fluid and provides proprioception.
Capsule and Ligaments
- The hip joint capsule is reinforced by ligaments, including the iliofemoral ligament, the pubofemoral ligament, andischiofemoral ligament.
- These ligaments are vital for joint stability, especially in the open packed position.
Close Packed Position
- The close packed position occurs at full hip extension, slight internal rotation, and slight abduction. It provides maximum joint stability.
- The open packed position occurs at 90 degrees of hip flexion, moderate abduction, and external rotation. The capsule and ligaments are more lax in this position.
Intracapsular Pressure
- The healthy hip typically has intracapsular pressure lower than atmospheric pressure.
- This negative pressure contributes to hip stability.
Osteokinematics
- Femoral-on-pelvic osteokinematics describes femur movement relative to a fixed pelvis.
- Pelvic-on-femoral osteokinematics describes pelvis and trunk movement relative to fixed femurs.
Lumbopelvic Rhythm
- This describes the coordinated movements of the pelvis and the lumbar spine during motions like walking.
- Ipsidirectional lumbopelvic rhythm occurs when the pelvis and the lumbar spine move in the same direction.
- Contradirectional lumbopelvic rhythm happens when the lumbar spine and pelvis move in opposite directions.
Arthrokinematics
- The femoral head generally remains seated within the acetabulum during hip motion.
- Movements like flexion, extension, abduction, adduction, internal, and external rotation are defined by the arthrokinematics of the hip.
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Description
Explore the fundamentals of biomechanics, focusing on the interplay of forces within the human body. This quiz delves into the anatomy and mechanics of crucial joints such as the hip, knee, and ankle. Understand kinematics, kinetics, and the significance of angles in joint structure and function.
