Chapter 2.2 Biomechanics

Question 1

Forms of energy that can impact a human 5

Answer 1

1. chemical
2. electrical
3. mechanical
4. radiant
5. thermal

Question 2

Chemical

Answer 2

Heat transfers from active chemical substances such as chloride, drain cleaner, acids or plants

Question 3

Electrical

Answer 3

Energy transfers from light socket, power lines or lighting

Question 4

Mechanical

Answer 4

Energy transfers from one object to another in the form of motion (e.g. a car hitting a tree).

Question 5

Radiant

Answer 5

Energy transfers from blast sound waves, radioactivity such as a nuclear facility or rays of the sun.

Question 6

Thermal

Answer 6

Energy transfer of heat in the environment to the host

Question 7

Kinetic energy - calculation

Answer 7

The energy of a body in motion is deemed as kinetic energy (KE).

• The amount of KE that an object has depends on the relationship been two variables = mass and velocity (speed).
• It is possible to work out what the KE is.
  • KE is equal to one half in the mass (m) multiplied by the square of its velocity (v2).
  K.E. = 1/2 mv2.

We need to be able to gauge if it is a LOW or high-energy event

Question 8

Types of energy forces (7)

Answer 8

1. unloaded
2. tension
3. compression
4. bending
5. shear
6. torsion
7. combined loading

Question 9

Energy forces and laws of physics - what do we need to know to determine a trauma pattern (2)

Answer 9

The distance and total surface area over which the energy is transferred are influential in determining injury patterns.

Question 10

Tension - define

Answer 10

Tension forces stretch by pulling at opposite ends.

e.g. tissues’ ability to resist when stretched. tendons/ligaments etc. can tear when overstretched.

Question 11

Compression - define

Answer 11

Compression forces crush by squeezing together

e.g. organs are crushed by internal structure or organs such as seatbelt worn between the abdomen causing compression of the small bowel or fractures to the spine

Question 12

Bending - define

Answer 12

Bending causes compression on the side the person is bending towards and tension on the opposite side

e.g. standing to a bending forward position

Question 13

Shearing - define

Answer 13

Shearing forces damage by tearing or bending by exerting force at different parts in opposite directions at the same time.

AAA is an example; the aorta is stretched beyond its capacity, the vessel is torn away from the attachment

Question 14

Torsion - define

Answer 14

Ends twist in opposite directions

Question 15

Combined loading - define

Answer 15

any combination of tension, compression, torsion, bending and/or shearing.

Question 16

External energy - forces (2)

Answer 16

AS energy traverses across the tissue it is absorbed by the cells.

• It can be exerted by acceleration and deceleration forces.

1. acceleration force; applied energy causes a sudden and rapid onset of motion e.g. forceful blow to the head
2. De-deceleration force; this occurs when energy is halted by a sudden stop. the more distance involved the less likely a severe injury is to occur. e.g. collision

Question 17

The internal forces that resist an applied external force are described as stress.

Name the 3 considerations

Answer 17

1. bone
2. muscle density
3. organ structures