Chap 5: Muscular System

Question 1

What is a muscle origin?

Answer 1

where the mm starts
more stable bone which the mm moves towards

Question 2

what’s the muscles insertion?

Answer 2

the more moveable bone which the mm is connected to

Question 3

what is normal resting length?

Answer 3

the length of the mm when not in use
the length of the muscle when it is not shortened or lengthened - that is, when there are no forces or stresses placed upon it

Question 4

what is irritability/excitability?

Answer 4

ability to respond to a stimulus
the ability to respond to a stimulus

Question 5

what is contractility?

Answer 5

the mm ability to contract and generate force when it receives adequate stimulation

Question 6

what is extensibility?

Answer 6

the mm ability to extend
the mm ability to stretch or lengthen when a force is applied

Question 7

what is elasticity?

Answer 7

the mm ability to recoil or return to normal resting length when the stretching or shortening force is removed

Question 8

what is passive tension

Answer 8

Stretching a muscle builds up passive tension, much like stretching a rubber band, and involves the noncontractile units of a muscle

Question 9

what is active tension

Answer 9

Active tension comes from the contractile units and the force generated can be compared with releasing one end of a stretched rubber band.

Question 10

what is tone?

Answer 10

Tone is the slight tension that is present in a muscle at all times, even when the muscle is resting.
Tone is a state of readiness that allows the muscle to act more easily and quickly when needed.

Question 11

what is excursion?

Answer 11

general ability of a muscle to shorten to ½ of resting length and stretch to approximately twice as far as can be shortened
The excursion of a muscle is that distance from maximum lengthening to maximum shortening.

Question 12

what is Active insufficiency?

Answer 12

occurs when a muscle cannot actively shorten any farther
The muscle runs out of contractile power before full joint ROM is reached
Occurs when 2-joint muscles attempt to perform full ROM at both joints

Question 13

what is passive insufficiency?

Answer 13

occurs when a muscle cannot stretch/lengthen any farther without damage
The muscle runs out of available length before full joint ROM is reached; occurs in 2-joint muscles in general

Question 14

what is Adaptive Lengthening

Answer 14

Poor posture can often result in a muscle being in a chronically overstretched (lengthened) state where it adopts an abnormally long resting length.
Stretching a muscle to increase it’s length

Question 15

what is adaptive shortening

Answer 15

in situations when a muscle is left in a shortened position for a prolonged period of time without moving through its full excursion, it undergoes adaptive shortening in which the resting length and amount of extensibility decrease.

Question 16

what is tenodesis?

Answer 16

A person who is quadriplegic and has no voluntary ability to open and close the fingers can use this principle to grasp and release light objects. By supinating the forearm, the weight of the hand and gravity causes the wrist to fall into hyperextension. This closes the fingers, creating a slight grasp. Pronating the forearm causes the wrist to fall into flexion, thus opening the fingers and releasing an object.

Question 17

what is isometric muscle contraction

Answer 17

When a mm contract producing force without changing the force of the muscle

An isometric contraction occurs when a muscle contracts, producing force without changing the length of a muscle

Question 18

what is isotonic muscle contraction

Answer 18

Contractions that involve shortening of the muscle

Question 19

what is a concentric contraction

Answer 19

A concentric contraction occurs when there is joint movement, the muscles shorten, and the muscle attachments (origin and insertion ) move toward each other. It is sometimes referred to as a shortening contraction.

Question 20

what is an eccentric contraction

Answer 20

An eccentric contraction occurs when there is joint motion but the muscle appears to lengthen; that is, the muscle attachments separate

Question 21

what is acceleration and deceleration

Answer 21

the speed inwhich the muscle moves

Question 22

what is force of gravity

Answer 22

this is when you allow gravity to help or resist muscle movement

Question 23

what is gravity-elminated with mm contraction

Answer 23

this is where a pully type device or gravity-eliminated position like side-lying with the arm supported, to aid in movement when the pt is unable to make the movement themselves.

Question 24

roles of muscles: agonist

Answer 24

muscle or muscle group that causes the motion
also called the prime mover

Question 25

roles of muscles: antagonist

Answer 25

potenially oppeses the prime mover In the case of elbow flexion, the antagonist is the triceps muscle.

Question 26

role of muscles: co-contraction

Answer 26

When the antagonist contracts at the same time as the agonist

Question 27

role of muscles: stabilizer

Answer 27

A stabilizer is a muscle or muscle group that supports, or makes firm, a part allowing the agonist to work more efficiently. For example, when you do a push-up, the agonists are the elbow extensor muscles. The abdominal muscles (trunk flexor muscles) act as stabilizers to keep the trunk straight, whereas the arms move the trunk up and down. also called a fixator.

Question 28

role of muscles: neutralizer

Answer 28

contracts to prevent the unwanted motion

Question 29

roles of mucles: synergist

Answer 29

A synergist is a nonspecific term describing a muscle that works with one or more other muscles to enhance a particular motion.

Question 30

what is (line) angle of pull

Answer 30

the path which the muscles traves, it's insertion and origin, joints is crosses, etc.

Question 31

Kinetic chains: open kinetic chain

Answer 31

distal limb segment is free to move while proximal segment remains stationary; static lunges, push-ups, squats, pull ups If you were to remain seated and extend your knee, your hip and ankle joint would not move. This is an open kinetic chain activity.

Question 32

Kinetic chains: close kinetic chain

Answer 32

distal limb segment is fixed; free to move i.e., biceps curls, knee extensions, walking lungesdistal limb segment is fixed while proximal segment moves; sittostand

Question 33

Usually when a muscle contracts, the distal attachment moves toward the proximal attachment. What is another name to describe the distal attachment?

Answer 33

Insertion

Question 34

Usually when a muscle contracts, the distal attachment moves toward the proximal attachment. What is another name for the proximal attachment?

Answer 34

origin

Question 35

What is the term that describes a muscle contraction in which the proximal end moves toward the distal end?

Answer 35

Reversal of muscle action

Question 36

The flexor carpi radialis performs wrist flexion and radial deviation. The flexor carpi ulnaris performs wrist flexion and ulnar deviation. In what wrist action do the two muscles act as agonists?

Answer 36

Agonists in wrist flexion

Question 37

The flexor carpi radialis performs wrist flexion and radial deviation. The flexor carpi ulnaris performs wrist flexion and ulnar deviation. In what wrist action do they act as antagonists?

Answer 37

Antagonists in ulnar/radial deviation

Question 38

The following chart identifies the hip motions of three muscles. Hip extension is the desired motion. Gluteus Maximus: Extension & Lateral Rotation   Hamstrings: Extension    Gluteus minimus: Medial Rotation Which of these muscles are acting as agonists in hip extension?

Answer 38

Gluteus maximus and hamstrings

Question 39

The following chart identifies the hip motions of three muscles. Hip extension is the desired motion. Gluteus Maximus: Extension & Lateral Rotation   Hamstrings: Extension    Gluteus minimus: Medial Rotation What motion must be neutralized so the agonists can do only hip extension?

Answer 39

Hip lateral rotation

Question 40

The following chart identifies the hip motions of three muscles. Hip extension is the desired motion. Gluteus Maximus: Extension & Lateral Rotation   Hamstrings: Extension    Gluteus minimus: Medial Rotation What muscle must act as a neutralizer to rule out the undesired motion?

Answer 40

Gluteus minimus

Question 41

What is the term for the situation in which a muscle contracts until it can contract no farther, even though more joint range of motion is possible?

Answer 41

Active insufficiency

Question 42

Is walking downhill a concentric or an eccentric contraction of your quadriceps muscle?

Answer 42

Eccentric

Question 43

Sitting with a weight in your hand, forearm pronated, elbow extended, and shoulder medially rotated, slowly move your hand out to the side and raise it. What is the joint motion at the shoulder?

Answer 43

Shoulder abduction

Question 44

Sitting with a weight in your hand, forearm pronated, elbow extended, and shoulder medially rotated, slowly move your hand out to the side and raise it. Is an isometric, concentric, or eccentric muscle contraction occurring at the shoulder?

Answer 44

Concentric

Question 45

Sitting with a weight in your hand, forearm pronated, elbow extended, and shoulder medially rotated, slowly move your hand out to the side and raise it. What muscle group is contracting at the shoulder?

Answer 45

Shoulder abductors

Question 46

Sitting with a weight in your hand, forearm pronated, elbow extended, and shoulder medially rotated, slowly move your hand out to the side and raise it. What type of muscle contraction is occurring at the elbow?

Answer 46

Isometric

Question 47

Sitting with a weight in your hand, forearm pronated, elbow extended, and shoulder medially rotated, slowly move your hand out to the side and raise it. What muscle group is contracting at the elbow?

Answer 47

Elbow extensors

Question 48

Sitting with a weight in your hand, forearm pronated, elbow extended, and shoulder medially rotated, slowly move your hand out to the side and raise it. What is the joint motion at the shoulder?

Answer 48

Shoulder flexion

Question 49

Sitting with a weight in your hand, forearm pronated, elbow extended, and shoulder medially rotated, slowly move your hand out to the side and raise it. Is an isometric, concentric, or eccentric muscle contraction occurring at the shoulder?

Answer 49

Concentric

Question 50

Sitting with a weight in your hand, forearm pronated, elbow extended, and shoulder medially rotated, slowly move your hand out to the side and raise it. What muscle group is contracting at the shoulder?

Answer 50

Shoulder flexors during first 90 degrees

Question 51

Sitting with a weight in your hand, forearm pronated, elbow extended, and shoulder medially rotated, slowly move your hand out to the side and raise it. What type of muscle contraction is occurring at the elbow?

Answer 51

Eccentric

Question 52

Sitting with a weight in your hand, forearm pronated, elbow extended, and shoulder medially rotated, slowly move your hand out to the side and raise it. What muscle group is contracting at the elbow?

Answer 52

Shoulder extensors during second 90 degrees

Question 53

Identify the following in terms of open- or closed-kinetic chain activities: Wheelchair push-ups

Answer 53

Wheelchair push-ups: closed-chain activity

Question 54

Identify the following in terms of open- or closed-kinetic chain activities: Exercises with weight cuffs

Answer 54

Exercises with weight cuffs: open-chain activity

Question 55

Identify the following in terms of open- or closed-kinetic chain activities: Overhead wall pulleys

Answer 55

Overhead wall pulleys: open-chain activity

Question 56

What position would a person have to be in to perform shoulder abduction and adduction in a gravity-eliminated position?

Answer 56

Supine (or prone) lying

Question 57

For a muscle to have an effective angle of pull to be a shoulder flexor and not a shoulder abductor, it would have to span the shoulder on what surface?

Answer 57

Anterior surface

Question 58

The rectus femoris flexes the hip and extends the knee. The vastus medialis extends only the knee. In what position must the hip and knee be placed to be able to stretch only the vastus medialis?

Answer 58

The hip must be flexed to place the rectus femoris on slack, and the knee is flexed.

Question 59

If you wanted a muscle to lift a very strong load, what muscle fiber arrangement would you want?

Answer 59

Oblique

Question 60

If you wanted a muscle to contract through a very great range, what muscle fiber arrangement would you want?

Answer 60

Parallel

Question 61

In terms of muscle tissue characteristics: What can a muscle do that a rubber band cannot?

Answer 61

Contract

Question 62

In terms of muscle tissue characteristics: What characteristic does a rubber band have that chewing gum does not?

Answer 62

Elasticity

Question 63

Please perform an analysis of what is happening to the length of the rectus femoris muscle at both the hip and the knee when an individual moves from a seated position to a standing position.

Answer 63

The rectus femoris is lengthening over the anterior aspect of the hip and contracting (shortening) over the anterior aspect of the knee.