Deck 1: Biomechanical Applications to Joint Structure and Function

Question 1

An eccentric muscle contraction is an example of a second-class lever system.

Answer 1

True

Question 2

Considering the figure below,which of the following answers best represents the direction of the resultant force?

A)
B)
C)
D)

Answer 2

C

Question 3

How do you determine the net effect of two muscle pulls applied to the same spot? What is this process called?

Answer 3

You find the resultant pull of the two forces by drawing the two forces,creating a parallelogram by adding sides parallel to each of the forces,and drawing a diagonal within the parallelogram.The resultant is the diagonal with its point of application at the original source and whose arrow head (limit of magnitude)is at the opposite corner of the parallelogram.This is called composition of forces.

Question 4

What happens to the center of gravity (CoG)of the body when the body segments are rearranged? What happens to the CoG if the right upper extremity is amputated?

Question 5

Explain how anatomical pulleys affect the magnitude and direction of a muscle force (Fms).

Question 6

Which of the following describes the phenomenon that causes a body moving at a constant speed to remain at that speed,unless it is acted upon by another body or force?

A) Impulse
B) Energy level
C) Law of Reaction
D) Law of Inertia

Question 7

A student is carrying all his books for his Fall semester courses (first year)in his right arm.What does the additional weight do to the combined center of gravity (CoG)of body and books? How will his body most likely respond to this change?

Question 8

Which of the following describes the phenomenon that when two forces come in contact,the second force will respond to the contact by the first force with equal magnitude and in the opposite direction?

A) Law of Inertia
B) Law of Reaction
C) Law of Acceleration
D) None of the above answers are correct.

Question 9

A ________________class lever is described by the fulcrum occurring at one end,followed by the resistance (load or weight)and then the force (effort).

A) First
B) Second
C) Third
D) Fourth

Question 10

When the centers of mass (CoM)of two adjacent segments are combined,the combined CoM will be located somewhere along a line connecting the two individual CoMs.

Question 11

When you raise a cup to your mouth,a ________________of motion occurs at the elbow joint.

A) rotation only
B) translation only
C) translation and rotation
D) None of the above answers are correct.

Question 12

What kind of force system do the fibers within a muscle form? Explain.

Question 13

Hip abduction from an anatomic position would occur in which plane?

A) Sagittal
B) Frontal
C) Transverse
D) Horizontal

Question 14

Is naming the plane of motion considered part of kinetics or kinematics? Why?

Question 15

Which of the following statements describes the relationship between joint reaction forces and the translational/rotatory component forces?

A) The contact force and translation component force run parallel to each other.
B) The contact force and rotatory component force run parallel to each other.
C) The shear force and translation component force run parallel to each other.
True/False
Indicate whether the statement is true or false.

Question 16

As your patient abducts her shoulder from 90° to 120°,the moment arm decreases.If the torque from the deltoid remains constant,the force of the deltoid would ________________as the shoulder abducted.

A) remain the same
B) increase
C) decrease
D) become 0 N
Figure 1-9

Question 17

Which of the following best describes torque?

A) The force a muscle generates
B) A force times the perpendicular distance from the line of force to the axis of rotation
C) A force times the distance measured along the lever from the line of force to the axis of rotation
D) The distance a muscle can move

Figure 1-7

Question 18

Upon what variables is the magnitude of friction dependent?

Question 19

In what type of lever is the M Ad always less than one?

A) First
B) Second
C) Third
D) Fourth

Question 20

The relative line of gravity changes with changes in body position.

Question 21

If not all of a muscle's force is contributing to rotation,what happens to the "wasted" force? Describe by resolution of forces.

Question 22

If you have a patient with a recent ligamentous injury to his knee,which of the following positions would you want to avoid and why: sitting,prone,supine,sitting with legs over the edge of the bed,or prone with knees flexed to 90°.

Question 23

If a force is applied at an angle to a lever (not 90°,not 0°),what is the process by which you determine the torque applied to the lever by that force?

Question 24

Using the values given in the following problem,determine whether the lever is in rotational or linear (translatory)equilibrium.