Podcast
Questions and Answers
What is the state in which there is no acceleration?
What is the state in which there is no acceleration?
What type of motion occurs when a joint moves?
What type of motion occurs when a joint moves?
What happens in a pure rolling motion?
What happens in a pure rolling motion?
Why is the combination of rolling, sliding, and spinning important in joint movement?
Why is the combination of rolling, sliding, and spinning important in joint movement?
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What happens to the femur during the last part of knee extension?
What happens to the femur during the last part of knee extension?
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What would happen to the knee joint if there were only rolling of the condyles of the femur on the tibial plateau?
What would happen to the knee joint if there were only rolling of the condyles of the femur on the tibial plateau?
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What occurs during anterior movement of the tibia?
What occurs during anterior movement of the tibia?
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What is the point of congruency in joint pairs called?
What is the point of congruency in joint pairs called?
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In which joint does the close-packed position occur at dorsiflexion?
In which joint does the close-packed position occur at dorsiflexion?
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What is the term for the position where the ovoid joint surfaces do not fit perfectly?
What is the term for the position where the ovoid joint surfaces do not fit perfectly?
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In which joint does the close-packed position occur at full extension?
In which joint does the close-packed position occur at full extension?
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What occurs when the joint is in a close-packed position?
What occurs when the joint is in a close-packed position?
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What is the advantage of the close-packed position in the hip and knee joints during standing?
What is the advantage of the close-packed position in the hip and knee joints during standing?
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What type of motion occurs in addition to angular motions in a joint?
What type of motion occurs in addition to angular motions in a joint?
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What is the result of the close-packed position in the MPJs during gripping action?
What is the result of the close-packed position in the MPJs during gripping action?
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What is the state of the ligamentous and capsular structures in the open-packed position?
What is the state of the ligamentous and capsular structures in the open-packed position?
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What is the benefit of the close-packed position in terms of joint stability?
What is the benefit of the close-packed position in terms of joint stability?
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What is the consequence of larger joint surfaces in the context of Range of Motion (ROM)?
What is the consequence of larger joint surfaces in the context of Range of Motion (ROM)?
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What occurs in an open kinematic chain?
What occurs in an open kinematic chain?
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Which of the following is an example of a closed-chain motion?
Which of the following is an example of a closed-chain motion?
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What happens to the thigh in the motion of standing to sit?
What happens to the thigh in the motion of standing to sit?
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What type of motion occurs during walking and stair climbing?
What type of motion occurs during walking and stair climbing?
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What happens to the leg in the motion of standing up from a chair?
What happens to the leg in the motion of standing up from a chair?
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What type of end-feel occurs when the motion is stopped by contact of bone on bone?
What type of end-feel occurs when the motion is stopped by contact of bone on bone?
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Which type of end-feel is characterized by pain on motion but absence of resistance?
Which type of end-feel is characterized by pain on motion but absence of resistance?
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What type of end-feel occurs when the limitation is from ligamentous, capsular, or muscle structures?
What type of end-feel occurs when the limitation is from ligamentous, capsular, or muscle structures?
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What is the term for a normal end-feel that is not characteristic of the normal joint end-feel and occurs at a different place in the ROM of a joint?
What is the term for a normal end-feel that is not characteristic of the normal joint end-feel and occurs at a different place in the ROM of a joint?
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Which type of end-feel is characterized by a rebound feel at the inner of ROM?
Which type of end-feel is characterized by a rebound feel at the inner of ROM?
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What type of end-feel occurs when the motion is stopped by the contact of adjacent soft tissues?
What type of end-feel occurs when the motion is stopped by the contact of adjacent soft tissues?
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Study Notes
Kinematic Chains
- A kinematic chain refers to a series of articulated segmented links, such as the connected pelvis, thigh, leg, and foot of the lower extremity.
- There are two types of kinematic chains:
- Open kinematic chain: the distal segment of the chain moves in space while the proximal segment is fixed or stable.
- Closed kinematic chain: the distal segment is fixed, and proximal parts move.
Examples of Kinematic Chains
- Squat: an example of a closed-chain motion.
- Leg curl from sitting in a chair: an example of an open-chain motion.
- Reaching or bringing the hand to the mouth: an open-chain motion.
- Performing a chin-up: a closed-chain motion.
- Standing to sit and sitting down in a chair: both are closed-chain motions.
- Walking and stair climbing: alternation of closed-chain motion and open-chain motion.
Convex-Concave Principle
- Normal interphalangeal joint movements follow the convex-concave principle.
- Close-packed position: the ovoid surfaces of joint pairs match each other perfectly in only one position of the joint, usually occurring at one extreme in the range of motion.
- Open-packed position: the ovoid joint surfaces do not fit perfectly and are incongruent.
Characteristics of Close-Packed Position
- Maximum area of surface contact occurs.
- The attachments of the ligaments are farthest apart and under tension.
- Capsular structures are taut (under tension).
- The joint is mechanically compressed and difficult to distract.
Characteristics of Open-Packed Position
- The ligamentous and capsular structures are slack.
- The joint surfaces may be distracted several millimeters.
- This position allows the necessary motions of spin, roll, and slide and may decrease joint friction.
Mechanical Advantage of Close-Packed Position
- Provides great mechanical stability to the joint.
- Reduces the need for muscle forces to maintain a position.
- Examples: standing position, gripping action.
Accessory Motions
- Joint surfaces can be moved passively a few millimeters in translatory motion, called accessory movements or joint play.
- Examples: equilibrium, dynamics.
Arthrokinematics
- Three types of motion can occur between the two articulating surfaces: rolling, sliding, and spinning.
- In a pure rolling motion, each subsequent point on one surface contacts a new point on the other surface.
- In sliding and spinning, the same point on one surface contacts new points on the mating surface.
- Most normal joint movement has some combination of rolling, sliding, and spinning.
- The knee joint shows the combination of these movements most clearly.
Arthrokinematics in Sit-to-Stand
- Rising from a seated to a standing position: the femur is extended on the fixed tibia, the femoral condyles roll and slide so that they are always in contact with the tibial condyles.
- In the last part of knee extension, the femur spins (internally rotates on the tibia).
Clinical Importance of Arthrokinematics
- Arthrokinematics (combination of roll, slide, and spin) permits a large range of motion while using a small articular surface.
- If joints possessed only one of these motions, this would limit the range of motion.
End-Feel
- The end-feel is the resistance felt at the end of the range of motion.
- Normal end-feel: hard, firm, or soft.
- Examples: hard or bony end-feel, firm or springy end-feel, soft end-feel.
- Pathologic end-feel: an end-feel that is not characteristic of the normal joint end-feel and occurs at a different place in the range of motion.
- Examples: empty end-feel, hard end-feel, springy end-feel, sudden hard-feel, capsular feel.
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Description
Test your knowledge of kinematics and arthrokinematics concepts, including equilibrium, dynamics, and types of motion in joints.
