4.2 Joint Movement, and muscle contractions Flashcards
Extension of a joint is best described as…
Increasing the angle between the two bones involved in that particular movement. (hinge joints always move with flexion an extension)
For example knee, flexion, and extension.
Knee extension increases the angle between the tibia and femur.
(see image attached)
Flexion of a joint is best described as…
Decreasing the angle between the two bones involved in that particular movement. (hinge joints always move with flexion an extension)
For example knee, flexion, and extension.
Knee flexion decreases the angle between the tibia and femur.
(see image attached)
Explain the concept of reciprocal inhibition.
Muscles pull on joints in pairs, these pairs are called antagonistic pairs.
Antagonistic pairs, work with the concept of reciprocal inhibition. The Agonist contracts while the antagonist relaxes.
When the agonist motor neuron is stimulated, the motor neuron to the antagonist is inhibited, preventing it from contracting strongly”
Explain the movements Abduction and Adduction and give an example.
Abduction
The movement of a limb (arm or leg) away from the midline of the body.
Adduction
The movement of a limb (arm or leg) towards the midline of the body.
Example in pictures attached (note horizontal ab/adduction is also possible.
What is pronation and supination and give an example?
The ‘twist’ movement in an limb. E.g. twisting the hand from palm up to palm down position.
What is a Synergist muscle?
Assists Prime mover
When performing an exercise, other muscles may join in and assist the prime mover. These muscles are called synergists
What is a fixator muscle?
Stabilizes the joint which is moving.
Muscles can also contract isometrically to stabilize the origin to maintain a correct or stable position. When a muscle performs this function it is called a fixator
Which antagonistic pair is involved in Elbow flexion, and extension.
Flexion
AGONIST (prime mover) = Biceps Brachii
ANTAGONIST (relaxed) = Triceps Brachii
Extension
AGONIST (prime mover) = Triceps Brachii
ANTAGONIST (relaxed) = Biceps Brachii
Which antagonistic pair is involved in Shoulder flexion, and extension.
Flexion
AGONIST (prime mover) = Anterior Deltoid & Pectoralis Major
ANTAGONIST (relaxed) = Posterior Deltoid & Latissimus Dorsi
Extension
AGONIST (prime mover) = Posterior Deltoid & Latissimus Dorsi
ANTAGONIST (relaxed) = Anterior Deltoid & Pectoralis Major
Circumduction is possible at which type of synovial joint?
Ball and socket joints.
Hip joint
Shoulder joint.
How does rotation of a joint differ from circumduction?
The difference between?
Protraction - Retraction
Inversion - Eversion
Suppression - Depression.
What are the 5 different muscle contractions?
Isotonic
Isometric
Isokinetic
Concentric and Ecentric
Outline Isometric muscle contraction
Contraction with no change in muscle length
(tension but no movement)
(Ex. Arm wrestle)
Outline Isotonic muscle contraction
Tension with movement, Muscles moving
Two kinds of Isotonic contraction (Concentric and Eccentric)