Title: Announcements
1Announcements
- TTU and Graduate School Scholarships
- Departmental site and follow links to
scholarships - http//www.depts.ttu.edu/gradschool/scholarships/
- Deadlines begin in February (Feb. 3)
2Injury, Musculoskeletal Tissues Joints
- ESS 5310-001
- Lecture 2 (2-day)
- Reading WZ Chapters 1 2
3Part 1
4Epidemiology from Injury in U.S.
- 8 million people expected to die from injury in
U.S. - 40 ER admissions and clinics due to
unintentional injury - Resulting in an annual cost (1996) of 435
billion - 5th leading cause of death in U.S.
- 3rd leading cause of death if injury related to
homicide is categorized as unintentional injury
5Impact of Injury
- Remaining Lifespan following injury is 36 years
- Compare with 12 yrs for cardiovascular disease
- National Center for Health Statistics (1995)
- Unintentional injury as leading cause of death
(considering impact and years of potential life
lost) - Disabling Injury
- Every 10 minutes, 2 people killed and 370 incur a
disabling injury (NSC) - 8.3 million each year
6Terminology
- Mechanics
- Branch of science that deals with the effects of
forces and energy on objects - Mechanism
- Fundamental physical process responsible for a
given action, reaction, or result
7Musculoskeletal Injury Considerations
- Study of injury breaks across several
disciplines - Anatomy Physiology
- Mechanics
- Kinesiology
- Medicine
- Engineering
- Psychology
- Thus proper study of musculoskeletal injury is by
default a multidisciplinary approach.
8Historical Perspective
- Evidence of lesions, fractures and arthritis
exist from assorted archeological discoveries and
uncovered skeletal remains - Nature of injuries leads to insight as to the
history of an era - Splints and surgical implements have been
discovered as well - Drawing a time-line to the development of todays
treatments of injury - e.g. casts and splints, knives dating back to
1000BC (predating Hippocrates)
9Greeks, Romans and
- Decline of Roman Empire (476)
- Dark Ages took Europe
- Progress in medical science virtually ceased
- Meanwhile in Asia
- Tang Dynasty (China, 619-901)
- Surgery recognized as special medical branch
- Orthopedic treatment of fracture and dislocation
- Hippocrates (460-377 BC)
- Began evolution of medical practice (specialized)
- Study and treatment of injury
- Homer (Iliad)
- Made reference to over 100 specific wounds
- Galen (129-199)
- Credited with defining the direction of medical
treatment for next 1500 years - Nature of muscle contraction anatomy
- Treatment of spinal deformities (kyphosis,
scoliosis, lordosis)
10Progress in Medical Industry
- The enhanced knowledge of human anatomy drove the
understanding of function. - Leonardo da Vinci (1452-1519)
- Intrigued by pain and trauma
- Illustrations of painful expressions
- Joints serve as shock absorbers (impact)
- That which gives more resistance to a blow
suffers most damage - Industrial Revolution (19th century)
- Accelerated advancements in medicine
- Clinical arthroscopy (Bircher, early 1900s)
- Accompanied by an increase in injury caused by
machinery - Progress continues today
11Epidemiology
- Epidemiology
- Study of the incidence, distribution, and control
of disease and injury in a given population - 2 Kinds
- Descriptive frequency an distribution of a
particular injury - Rely on categorizing incidents according to the
severity of the injury, location where the injury
took place, type of disability, subset of
population affected and type of activity - Mutually exclusive, Exhaustive, Useful
- Analytical attempts to pinpoint the causal
relation - More difficult and time consuming
12In the last decade
- Practicality and improved technology of joint
replacement - Laser surgery
- Advanced imaging techniques (e.g. MRI, 3D
sonogram) - Microsurgery
- Computer/robot assisted surgery
13Injury Terminology
- Injury Incidence
- Number of new injuries in a fixed time period
divided by the number of people at risk - Injury Prevalence
- Number of people with an injury divided by the
number of people at risk - Risk Factor
- Something that contributes to increasing the
probability of an injury - e.g. Occupation, activity pattern, age, sex,
injury history, recreational pursuits,
environmental conditions
14Injury Terminology
- Injury Rate
- Number of injuries in a population divided by a
reference measure (e.g. number of people in
population, hours of exposure) - e.g. Estimates of metatarsal stress fractures per
1000 runners, concussions per 100,000 contact
hours - Relative Risk
- Measure of the likelihood of an injury happening
in one group versus another group - Requires knowledge of reliable incidence data for
both groups
15Sources for Reliable Injury Data
- National Safety Council
- Insurance Companies
- Law Enforcement Agencies
- Occupational Safety and Health Administration
(OSHA) - Traffic Safety Boards
- Much of the available data are on injury-related
death - Raises questions as to what data are actually
reported?
16Some Statistics
- Deaths due to injury are higher in young people
- Accidental injury is the leading cause of death
in 1-44 year olds (1995) - Accidental injury is 2 cause of death in young
adults (ages 25-44y) (CDCP) - AIDS surpassed Injury as 1 in 1995
- Accidental injury is still 1 in children
17Health Care Perspectives
- Health Care Professionals
- Prevention, diagnosis, treatment, analysis,
technology advancement, rehabilitation - Those affected by injury
- Engineers, safety consultants, supervisors,
parents, teachers, coaches - Emergency medical physicians and staff
- Physicians, athletic trainers, allied health
professionals - Physical and occupational therapists
18Economic Perspective
- Economic Impact
- Public policy (, legislation, health care)
- Committee on Trauma Research, 1985 (Injury in
America highlighted injury cost and economic
impact) - Direct cost, morbidity costs, mortality costs
- Estimated annual cost 200 billion (1993), 430
billion (1995) - Economic Statistics from 1995
- 2 million individuals hospitalized as a result of
injury - 10 of hospital discharges and 16 of hospital
days - Ages 15-44 years, injury-related death resulted
in 3.7 million years of life lost - Ages 15-44 years, 2.7 million years of lost
productivity due to either temporary or permanent
disability - For every person hospitalized, 25 people sustain
injury needing medical attention
19Psychological Perspective
- Psychological factors may influence likelihood
and severity of injury and the course of healing
and rehabilitation - Risk behaviors, predisposition to injury, human
error and accidents, theories of causation, risk
evaluation, and emotional response to injury - Injury likelihood is influenced by
- Task, environment, persons psychological state
20Human Error
- Inappropriate or undesirable human decision of
behavior that reduces, or has the potential for
reducing, effectiveness, safety, or system
performance - Incidence
- Direct action of the injured person
- Indirect poor decision made by an engineer in
design process - Methods of Reduction
- Selecting people with appropriate skill and
capability - Proper training
- Effective equipment design, operation procedures,
and environment
21Accident Theory
- Accident-Proneness
- Some people are just more prone to accidents
- Accident-Liability
- People are prone to accidents in certain
situations (temporary) - Capability-Demand
- Accidents increase when job demands exceed worker
capability - Adjustment to Stress
- Accidents increase in high-stress situations in
excess of individuals ability to cope - Arousal-Alertness
- Accidents are more likely when arousal is too low
or too high - Goals-Freedom-Alertness
- Freedom of workers to set their own goals results
in high-quality performance, which reduces
accidents - No one theory holds sufficiently for all accident
cases - Thus, (as with most theories) a combination of
any or all may apply
22Contributing Factors
- Management
- Physical environment
- Equipment design and operation
- Task or nature of work itself
- Social and psychological environment
- Workers and co-workers
23Risk
- Likelihood of injury or death associated with a
particular object, task, or environment - Perception of risk may be distorted by
- Overestimation of expertise and experience
- Overemphasizing situations receiving media
attention - Adoption of It cant happen to me philosophy
24Approaches to Injury Prevention
- Injury Control
- Strategies of prevention
- Modification of hazards rate of occurrence
- Protection
- Stabilization, repair and rehabilitation of
damage/injury - Health and Safety Education
- Seeks to reduce the incidence and severity of
injury through education and knowledge - Injury Prevention Strategies
- Persuade/Educate to alter behavior LEAST
EFFECTIVE - Require changes in individual behavior (e.g.
enforce laws and safety protocols) - Automatic protection by product or environmental
design (e.g. air bags, automated seat belts,
anti-lock brakes) MOST EFFECTIVE
25Scientific Perspective on Injury
- Anatomists
- Structures and tissues
- Physiologists
- Repair and remodeling process
- Psychologists
- Behavioral aspects
- Engineers
- Equipment and structures to prevent and minimize
injury - Physics, Mechanics and Energy are key
- Thermal, electrical, magnetic, and chemical
energy can cause injury, but MOST injuries
involve mechanical energy - Biomechanics - logical discipline to study
musculoskeletal injury
26Priority for Biomechanics Research
- Injury mechanism clarification and understanding
- Quantification of the injury-related responses of
tissues (e.g. nervous system, joints, muscles) - Defining limits of human tolerance to injury,
especially for high risk or low visibility
populations (e.g. children, women) - Improvements in injury assessment technology
(e.g. computer simulations, crash test dummies,
diagnostic tools) - Training organization development (training
institutions, programs, fellowships)
27Part 1 Summary
- Epidemiology and Risk
- Database sources and statistics
- Perspectives on Injury
- Healthcare, Economic Impact, Psychological
- Human Error
- Accident Theory and Contributing Factors
- Injury Prevention
- Injury Biomechanics Research
28Part 2
29Joints
- Arthology
- Classification of joints and joint motion
- Categories of Joints
- Joints without cavity
- Synarthrodial (immovable)
- Amphiarthrodial (slightly movable)
- Joints with a cavity
- Diarthrodial (movable)
30Joints without Cavities
- Synarthrodial or Fibrous
- Bones held together by fibrous articulations
- Little or no movement
- Example
- Sutures in skull, tibiofibular joint
- Amphiarthrodial or Cartilaginous
- Hyaline cartilage or fibrocartilage holds joints
together - Little movement (but more than synarthrodial)
- Example
- Intervertebral discs
31Types of Diarthrodial Joints
32Table 2.3
33Form and Function
- Structure of the human musculoskeletal system
somewhat dictates function - Different joints allow rotations in only certain
planes, while restricting motion in other planes - Think of the joint structure and how the
muscle-tendon complex crosses the joint - Then think of the motion that is allowed at the
joint - Example Hip versus Knee
34Joint Structure vs. Function
- In the musculoskeletal system
- Structure (morphology) often determines function
- Can you think of some examples?
35Structure Dictating Function
- Knee Joint (condylar)
- Flexion and Extension
- Allows some anterior translation
- Also allows slight rotation during full extension
- Cervical Vertebrae
- Large range of motion (flexion, extension,
rotation, lateral flexion) - Small, and not weight bearing
- Lumbar Vertebrae
- Good range of motion in flexion and extension
(less than cervical) - Large, weight bearing
- Thoracic Vertebrae
- Very little range of motion (Why?)
- Fairly large but not as large as lumbar
- Can you think of other examples?
36Joint Structure vs. Function
- In the musculoskeletal system
- Structure (morphology) determines function
- Several examples noted
- Does or can function influence structure?
- What are some examples?
37Types of Diarthrodial Joints
Plane or Gliding Joint Two flat surfaces slide
over one another (Ex Carpals)
38Degrees of Freedom
- Number of planes in which a joint can move
- 1 DOF
- Uniaxial (hinge joint)
- Example Inter-phalangeal (flex-extend)
- 2 DOF
- Biaxial
- Example Wrist (flex-extend, ulnar-radial
deviation) - 3 DOF
- Triaxial
- Example Shoulder (flex-extend, abd-add, IR-ER)
39Joint Formatione.g. Knee
- 26-28 day embryo
- Occurs between weeks 4 to 10 in human embryo
- Basic Process
- Mesenchymal cells gather in developing limb
- Blastema
- Produces capsule, ligaments, synovial lining, and
menisci - Bones at this stage are basically cartilage
undergoing ossification - Interzonal mesenchyme condenses
- Articular disk (eventual joint plate formation)
- About 10 weeks later the joint is fully developed
- Cavity becomes synovial cavity
- Movement is important in proper embryonic
development
40(No Transcript)
41Part 2 Summary
- Joints (Arthrology)
- Degrees of Freedom
- Joint Development
42Part 3
43Overview
- Embryology
- Types of Tissues
- Epithelial, Nervous, Muscle, Connective
- Constituents of Connective Tissue
- Cells, Extracellular Matrix, Tissue Fluid
- Specific Tissue Comparisons
- Bone
- Cartilage
- Ligament, Tendon Fascia
- Muscle
- Joints
44Embryology
- Day 1
- Fertilization produces zygote
- Day 5
- Zygote becomes embryo
- Blastocyte (cell mass)
- Ectoderm Cell boundary layer along amniotic sac
- Endoderm Cell boundary layer along yolk sac
- Day 16
- Evidence of spinal cord
- Intraembrionic Mesodermal Layer is produced
- Layer of cells spread between endoderm and
ectoderm - Day 20
- Distinct neural structures (plate, groove, and
folds) - First somites appear
- Cuboidal bodies that create distinct elevations
and thus contours of embryo
45Embryology
- Week 4
- Cell proliferation and migration, creating the
sclerotome - Sclerotome condenses near notchcord (remaining
wall of somite) - Sclerotome gives rise to the dermatome
- Dermatome produces cells which form the myotome
- Myotome eventually gives rise to musculature
46Embryology
- Mesenchyme
- Undifferentiated cells of sclerotome
- Progenitor tissue of adult connective tissues
(e.g. cartilage, ligament, fascia, tendon, blood
cells, vessels, skin, bone, muscle) - Unique in their ability to differentiate into a
variety of cells (e.g. fibroblasts,
chondroblasts, osteoblasts)
47Types of Tissues
- Four Types of Tissue
- Epithelial
- Nervous
- Muscle
- Connective
48Epithelial Tissue
- Covering or lining tissue
- Derived from the two embryonic layers (endoderm
and ectoderm) - Functions
- Absorb, secrete, transport and excrete tissue
fluid - Protect underlying organs or tissues
- Characteristics
- No capillaries
- Nourished by tissue fluid from capillaries of
connective tissues - Not strong, but firmly bound to connective tissue
(only a thin layer of basement membrane) - Cells are continuously generated and lost
49Epithelial Tissue
- Structure
- Simple
- Single layer of cells
- Stratified
- 2 or more layers of cells
- Shape
- Squamous
- Cuboidal
- Columnar
50Epithelial Tissue
- Prominent role
- Mechanically weak, although serving as a
protective layer for organs and tissues beneath - Diffusion of fluids and heat
- Bioelectric conduction
51Nervous Tissue
- Develops from the ectoderm
- Comprises main parts of the nervous system
- Brain
- Spinal cord
- Peripheral nerves
- Nerve endings
- Sense organs
52Nervous Tissue
- Structure
- Neuron (nerve cell)
- Basic unit of nervous tissue
- Function
- Communication
- Characteristics
- Irritability (reacts to chemical or physical
stimulii) - Conductivity (transmit impulses from one location
to another)
53Nervous Tissue
- Dendrites
- Conduct nerve impulses toward the cell body
- May be many dendrites per cell
- Axons
- Conduct nerve impulses away from the cell body
- Only one axon per cell
- Nerve tissue may be injured by excess tension or
compression
54Muscle Tissue
- Developed from mesoderm
- 3 Categories
- Skeletal
- Smooth
- Cardiac
- Primary Function
- Conduction of impulses
- Contraction
55Skeletal Muscle
- Characteristics
- Striated muscle
- Fibers exhibit cross striations
- Multinucleated cells
- Voluntary control
- Surrounded by a layer (sheath) of connective
tissue which blends into tendon - Primary Function
- Generating force
- Maintain posture
- Produce body movement
56Smooth Muscle
- Characteristics
- More multidirectional cell organization
- Does not appear striated
- Under involuntary control
- Location
- Walls of tubes in arteries, intenstine, and
respiratory systems - Sympathetic and Parasympathetic nervous system
innervations
57Cardiac Muscle
- Characteristics of both skeletal and smooth
muscle - Striated
- Involuntary (generally)
- Heart Tissue
- Nervous stimulation results in a single
contraction from the entire tissue (functional
syncytium)
58Connective Tissue
- Derived from the mesoderm
- Cell Characteristics
- Soft
- Easily deformed
- In itself unable to contract or transmit loads
- Extracellular Matrix (of each specialized tissue)
- Dictates tissue form
- Composition of matrix establishes physical
characteristics - Soft, gel-like (e.g. skin, ligament)
- Rigid matrix (e.g. bone)
- Primary Role
- Produce and maintain the extracellular matrix
(each appropriately of bone, cartilage, tendon,
ligament)
59Connective Tissue
- Principal Fibers
- Collagenous
- Reticular
- Elastic
- Physical Structure
- Loose
- Dense (2 kinds)
- Dense Irregular
- Loose, randomly interwoven fibers (e.g. fascia)
- Dense Regular
- Organized fibers (e.g. tendon, ligament,
aponeuroses)
60Loose Connective Tissue
- More prevalent than dense
- 4 Basic Types
- Fibroelastic
- Areolar
- Reticular
- Adipose
- Fiber Make-up
- Elastic fibers, thus extensible
- Collagen
- Liquid extracellular matrix that bathes the cells
and fibers
61Fibroelastic Tissue
- Loose, woven network encapsulating most organs
(mesh-like) - Collagen organization allows extensibility
- Stretch initially does not deform fibers, as
first fibers become aligned with load - Contrast with Dense (arranged in parallel)
- Since collagen is already in line with load,
fibers quickly resist applied tensile load - Elastic fibers help return tissue back to
original position after load is released
62Areolar Tissue
- Loose connective tissue
- Saturates almost every area of the body
- Characteristics
- Fibroblasts and Macrophages are abundant
- Collagenous, elastic and reticular fibers give
limited strength - Generally weak and easily pulled apart
- Reticular fibers serve as boundary between
Areolar and other structures
63Reticular Tissue
- Loose Connective Tissue
- Make-up
- Reticular fibers and primitive cells
- Resembles early mesenchymal tissue
- Primitive cells can differentiate into
fibroblasts, macrophages, and plasma cells - Location
- Near lymph nodes
- In bone marrow, liver and spleen
- Around nerves, muscles and blood vessels
64Adipose Tissue
- Loose Connective Tissue
- Appears an aggregate of fat cells surrounded by
areolar tissue - Any loose connective tissue can accumulate fat
- When fat predominates the tissue is called
adipose - Make-up
- Reticular fibers surround each fat cell
- Capillaries found between cells
- Increased vascularity enables increased
metabolism of tissue - Location
- Around organs in abdomen, under skin, and in bone
marrow - Function
- Prevention of heat dissipation
- Act as cushion for skeleton during impacts
65Connective Tissue Constituents
- Cells
- Extracellular matrix
- Tissue Fluid
66Cells
- Resident (stable, maintain extracellular matrix)
- Undiffentiated Mesenshymal Cells (Stem Cells)
- Fibroblasts, osteoblasts, chondroblasts (become
-cytes as mature cells) - Migratory (wandering)
- Macrophages, monocytes, basophils, neutrophils,
eosinophils, mast cells, lymphosytes, plasma) - Travel via bloodstream usually in reaction to
injury - Macrophage (defense system)
- Mast Cell (heparin, anticoagulant)
- Heparin (anticoagulant)
- Histamine (vasodilator)
- Serotonin (vasoconstrictor)
67Extracellular Matrix
- Blend of protein fibers (collagen, elastin),
matrix glycoproteins, and tissue fluid - Collagen
- Most abundant protein in human body
- Comprises 30 of total protein
- Organization of fibers is tissue specific
- All key connective tissue cells can produce
collagen - More than 20 different types of collagen
discovered - Location
- Type 1 (most abundant)
- Skin, bone, tendon, ligament, cornea
- Type II
- Cartilage
- Type III
- Loose connective tissue, dermis of skin, blood
vessel walls
68Extracellular Matrix
- Elastic Fibers
- Components
- Elastin
- Microfibrils (small bundles embedded in elastin)
- Structure
- More slender and extensible than collagen
- Characteristics
- 150 stretch capability before rupture
- Other
- Complex glycoproteins
- Proteoglycan (between fibers and ground substance)
69Tissue Fluid
- Filtrate of blood
- Location
- Intercellular (interstitial) spaces
- Function
- Aids in transport of material between capillaries
and cells in extracellular matrix - Return waste to venous end for removal
- Lymphatic system may depose wastes
- If blockage occurs in lymphatics, tissue fluid is
trapped and swelling results
70Bone
- Characteristics
- Hardest and strongest tissue in the body
- Function
- Protects vital organs
- Mineral storehouse
- Houses bone marrow hematopoietic cells (blood
cell formation) - Provides levers allowing muscles to control
movement - Continuous remodeling due to
- Stresses
- Alterations in mechanical load
- Changes in systemic hormones
- Changes in serum calcium levels
- Osseous (bone tissue)
- Same make-up, different function
- Cortical (compact, very dense, outer layer)
- Cancellous (spongy, very porous, inner layer)
71Cartilage
- Contains cells and extracellular matrix
- 3 kinds of cartilage
- Hyaline (most abundant)
- Elastic
- Fibrocartilage
- Characteristics
- Develops from mesenchyme
- Lack of intrinsic blood vessels, nerves or lymph
vessels - Necessary to receive nutrients from diffusion
72Tendon and Ligament
- Principal cells are fibroblasts
- Characteristics
- Regularly arranged dense fibrous tissue
- Fibers organized into parallel bundles
- Primarily contain fibers and extracellular matrix
components - Great tensile strength
- Able to resist stretch in essentially one
direction, essentially parallel to fibers - Includes tendons, ligaments and aponeuroses
73Fascia
- Catch all term
- Characteristics
- Dense, fibrous, unorganized tissue
- Collagenous with some elastic and reticular
elements - Structure
- Interwoven, meshlike, non-parallel fibers
- Location
- Sheaths around organs, blood vessels, bones and
cartilage - Dermis of the skin
- Function
- Provides framework and support for muscles
- Fibers withstand stretch in many direction due to
unorganized fiber arrangement
74Skeletal Muscle
- Prime movers of the nervous system
- Two major elements
- Contractile proteins
- Network of connective tissue
- Characteristics
- Stiffness (from fibrous connective tissues within
muscle belly and tendon) - Enhances tension transfer
75Skeletal Muscle
76Part 3 Summary
- Embriology
- Tissue Types
- Epithelial
- Nervous
- Muscle
- Connective
- Overview of Connective Tissues
- Bone
- Cartilage
- Tendons Ligaments
- Fascia
- Skeletal Muscle
77For next time
- Reading from Chapter 3
- Review of Biomechanical Concepts
- Kinematics and Kinetics
- Assignment 1