Midterm Flashcards Preview

Biomechanics-ME > Midterm > Flashcards

Flashcards in Midterm Deck (283)
Loading flashcards...
1

What is a primary injury?

• Results directly from the initial, immediate trauma associated with a particular mechanism of insult

2

What are the types of primary injury (3)?

• Direct or Extrinsic. Trauma occurs at point of impact where the force meets the body. Ex: contusion from a direct force
• Indirect or intrinsic. A force meets the body in such a way that energy is transmitted to another part of the body where the trauma is concentrated and the injury occurs. Ex: dislocated shoulder from falling on an outstretched hand
• Overuse injury. Acute repetitive friction, Chronic repetitive microtrauma

3

What is a secondary injury?

• Additional injury that occurs as a result of the primary injury.

4

What are the types of secondary injury?

• Short-term. Results from the sequelae of injury, if not managed properly. Affects injured ells on periphery of the primary lesion
• Long-term. Over time may lead to degenerative conditions. Increases total quantity of tissue damage. Potentially increases healing time

5

What is a secondary enzymatic injury?

• Lysosomes release enzymes (not specifically identified, perhaps phospholipases and acid hydrolases), which damage surrounding cells (cleave hydrocarbon chains from membrane phospholipids), and cell membrane loses integrity and polarity (swelling, cell death)

6

What is secondary hypoxic/ischemic injury?

• Thought by some to be more important than enzymatic injury. Failure of vasculature to supply enough blood (=ischemia). Vascular and inflammatory changes cause a period of hypoxia, causing a shift to anaerobic metabolism. Eventually there is inability to produce adequate ATP, failure of membrane ion pumps, swelling, cell death

7

Why does ischemia arise in secondary injury?

• Damaged blood vessels; hemostasis/clotting; inflammation induced hemoconcentration; thicker blood does not flow as well; increased extravascular pressure from expanding hematoma; pain induced muscle spasm; swelling of injured cells

8

What physiological problems does ischemia cause?

• 3 things. Hypoxia. Inadequate supply of nutrients(glucose, etc); inadequate removal of waste

9

What is tension?

• A force that pulls tissues (e.g muscle-tendon injuries); results in strain, cramp

10

What is compression?

• A forceful blow to tissues; results in contusion , fracture

11

What is shearing?

• A force that moves parallel to the tissues; Ex: vertebral disc injuries

12

What is torsion?

• A twisting or turning force; an end of an object is twisted in one direction and the other end is stabilized or twisted in the opposite direction

13

What is bending?

• A horizontal force causing the tissue to bend or strain; Ex: a spiral fracture or greenstick fracture

14

What is stretching?

• The elongation of tissue (e.g ligaments); Ex: strain, sprain

15

What do tendons resist?

• Tensile force

16

What do bones resist?

• Compressive force

17

What do ligaments resist?

• Tensile force

18

What do discs resist?

• Tension, compressive, shear and torsion forces

19

What is a bruise?

• Compression that causes bleeding under the skin

20

What is a contusion?

• An acute compression causing hemorrhage of a muscle tissue

21

What are muscle cramps?

• Acute painful involuntary muscle contraction caused by dehydration or an electrolyte imbalance

22

What is a muscle spasm?

• A reflex muscle contraction caused by acute trauma; serves to protect or guard an area

23

What is muscle hypertonicity?

• Increased activity of an otherwise normal muscle; no nerve or muscle pathology is present, but the resting tone of the muscle is greater than normal; may cause muscle imbalance with an inhibited/weak antagonist muscle

24

What is muscle spasticity?

• Increase in muscle tone at rest; characterized by increased resistance to passive stretch, exaggerated deep tendon reflexes and possibly clonus; the result of an Upper Motor Neuron Lesion (UMNL)

25

What is a sprain?

• Stretching or tearing damage to a ligament; if ligamentous fibers are torn, it is reasonable to assume that the other tissue fibers are likely to have been torn (muscle, joint capsule, disc annulus)

26

What are the grades of sprains?

• Grade 1 (0-20%): minimal pain and loss of function, mild point tenderness, little or no swelling, and no abdominal motion when tested; stability of the joint in intact
• Grade 2 (20-75%): moderate pain, loss of function and swelling, moderate joint instability present
• Grade 3 (>75%): extremely painful with a major loss of function, tenderness, swelling and severe instability; surgical repair is probably indicated

27

What causes a sprain? Examples?

• End range loading. Sudden load (whiplash); a direct blow (lateral force to knee causing MCL sprain); repetitive overload (keyboard, typing); sustained postural overload (long hours at a workstation of studying)

28

How does a sprain present clinically?

• Decreased active range of motion with pain, especially in the direction that stretches the ligament or capsule
• Decrease passive range of motion with pain, especially in the direction that stretches the ligament or capsule
• Isometric muscle contraction causes no pain
• Local tenderness and occasionally edema or bruising
• May have pain on weight bearing (especially grade 1 and 2)
• Palpatory defect may be present in more severe sprains
• May produce joint instability

29

What are the residual or late effects of sprains?

• Fibrosis; subluxation; instability; proprioceptive and coordination/control problems; atrophy of related muscle (e.g. vastus medialis obliquus in knee injuries)

30

What is a strain?

• Acute stretch, tear, or rip in the muscle or tendon