2. Richard V. Baratta, Ph.D., P.E. The Subro Grapevine

3.  Basics of tissue biomechanics  Basics of injury causation  Injury biomechanics  Situations & their injury potential  Reading medical reports regarding injuries  Warning! Graphic images...

4.  Anterior: Forward  Posterior: Rear  Medial: Towards the middle  Lateral: Towards the side  Proximal: Close to the head  Distal: Further from the head

5.  Bone  Ligament  Tendon  Muscle  Other soft tissues

6.  Hard, mineralized tissue  Cortical – outside, hard  Medullary – inside, “spongy”

7.  Stronger along the lines where forces are naturally applied

10.  If you read “spiral fracture”  Think torsion  If you read “transverse fracture”  Think bending  If you read “oblique fracture”  Think axial force  If you read “comminuted”  Think high energy/velocity

11.  Tough rope-like connective tissue between 2 bones

12.  Can tear in the middle (midsubstance tear)  Partial or complete

13.  Can pull off from a bone (avulsion)

14.  Contractile  Made up of sliding fibers  Create greatest force when forcefully stretched while contracting

15.  Most tears happen when contracts but is still being lengthened  Most tears happen at the junction between muscle and tendon

16.  Connect muscle to bone  Structure similar to ligaments

17.  Can tear  Partial or complete

18.  Can tear  Partial or complete  Can avulse  Takes great force to tear or avulse normal tendon  Happens when its muscle lengthens against a contraction

19.  Soft tissues surrounding joints  Thinner than ligaments  Contain joint fluid within the joint  Tear with dislocations

20.  Muscle  Strain  Tear  Rupture  Most often, muscle tears occur at junction between muscle and tendon  Ligament  Sprain  Partial Tear  Complete Tear  Joint Dislocation

21.  Skeletal System Anatomy  Upper Extremity  Lower Extremity  Spine  Head

23.  Radius, Ulna, Carpal bones  Ligaments  Tendons  Carpal Tunnel

24.  Carpal Tunnel Syndrome “cumulative trauma disorder”  Sprains  Fractures -

26.  Tennis Elbow (overuse)  Golfer’s Elbow (overuse)

27.  Fractures  Medial Ligaments

28.  Ball and Socket joint  Head of Humerus (ball)  Glenoid (socket)  Scapula  Acromion  Clavicle

29.  P-A force on shoulder or humerus

30.  Head of humerus comes forward (anterior) out of the socket

31.  Fairly uncommon (5%)  A-P force on shoulder or humerus  Seizures  Electrocution

32.  Downwards force on shoulder  Separates clavicle and rest of shoulder  Falls

33.  Muscles that rotate the upper arm  Injuries are to the tendons, not muscle fibers  Overuse or violent humerus external rotation  Depends on position (abduction)

34.  Femur, Tibia, Patella  Anterior and Posterior Cruciate Ligaments  Medial and Lateral Colateral Ligaments  Meniscus

35.  ACL prevents the tibia from moving forward on the femur and from rotating inwards  Cutting  Hyperextension

38.  Can be injured when a force tries bend the knee in a lateral direction  The ligament getting stretched is the one that gets injured

40.  Segment Curvatures  Segment Mobilities  Vertebral Body Sizes  Atlanto-Axial Joint

42.  Viscoelastic (like silly putty)  On high speed impacts, vertebral fractures are more likely than disc ruptures!  The only way to “pop a disc” on a single event is combined compression and bending (torsion helps)

44.  Injury pattern depends on mechanics  Danger of injuring spinal cord

47.  High Speed auto accidents  Often fatal  “Raccoon eyes” when not fatal

48.  Concussion – No structural damage, but some temporary loss of function  Contusion – More serious, bruising of the brain

49.  Subdural hematoma  Subarachnoid hemorrhage

50.  Direct impacts to the skull may injure brain on the same side, opposite side, or both sides of where the force is applied

51.  One of the most highly stressed joints in the body  Direct impact to the jaw or joint  TMJ syndrome – chronic!

53.  Mechanism of injury  Direct Contact  Exceeding range of motion  Indirect forces  Acceleration (brain injuries)  Loads sustained by tissue  Tissue tolerance to loads  Pre existing conditions (tissue attenuation)

54. I. Assessment of Situation Mechanics Witness statements Site inspection (regulations, standards, laws) Other information (police reports) Modeling II. Review of Medical Records Determination of claimed injuries Pre-existing conditions III. Analysis Correlation between claimed injuries and event mechanics Differentiate acute and chronic conditions Assess effect of pre-existing conditions

55.  Arrange in understandable terms  Oral report  Written report  Letter report  Formal report  Litigation support: Posters, demonstrative evidence, video animation  Coordination with attorney  Testimony

56. True? False?

57.  “Airbag blew up and flung my arm back and out”  “Bus hit a pothole and steering wheel jerked left” √ X

58.  “Fell back onto my outstretched hand”  “In the accident (sideswipe)” X √

59.  “Years of heavy labor”  “In the accident (low speed rear end collision)” X √  Dx: Lumbar disc herniation with osteophytes

60.  “In the accident (low speed rear end collision)”  “Airbag blew up and hit me in the jaw” X √

61.  26 y/o woman sustained fatal slip and fall injury in bathroom  Cause of death: brain hemorrhage due to head hitting toilet rim  Reported injuries: 2 scalp lacerations, contusion on right side of neck, anterior iliac spines  Non-reported injuries (evident photographically)  Abrasions on left side of neck (3), chin, both shoulders  Cut lip  2 parallel linear marks on back  Accidental slip and fall? X