▪Today we will be covering:▪What is orthopedics?

▪What are bones?

▪How to classify bones

▪Types of levers

▪Muscle forces

▪Fractures!

▪How to repair a fracture

▪A quick look at current research involving bones

▪All of this information is true for people and pets!

What are we going to learn?

That branch of medicine and surgery that is specially concerned with the preservation and restoration of the function of the skeletal system, its joints, and associated structures like ligaments and tendons

Orthopedics Defined

▪ Joint – where two or more bones come together

▪ Joint Cartilage – cartilage covering the ends of bones that are in contact with adjacent bones to allow smooth movement and shock absorption

▪ Tendon – connects muscle to bone

▪ Ligament – connects bone to bone

Associated Structures

1. Support/protection for body’s vital organs (for example, skull protects the brain, rib cage protects the heart & lungs)

2. Serve as levers in conjunction with joints, tendons, ligaments, and muscles for movement

3. Production of blood cells in bone marrow

4. Storage site for calcium & phosphorus

What Do Bones Do?

Two Types of Bone:

1.Compact Bone: bone’s outer layer, what we can see. It is dense, strong, and heavy

2.Spongy Bone – bone’s inner layer; self- organizes in response to the direction of weight put on it

Anatomy of a Typical Bone

▪ Long – long! Bones of limbs

▪ Short – short! Small bones of hands & feet

▪ Flat – flat! Bones on top of skull

▪ Sesamoid – small bones embedded in tendon as it crosses a bony prominence. Found in digital tendons.

▪ Irregular – jutting processes give these bones an irregular shape. Found in pelvic bone.

Classification of Bones

Quiz!Can you identify what type of bones these are?

❏ flat bones

❏ sesamoid bone

❏ short bones

❏ irregular bone

Quiz!Can you identify what type of bones these are?

❏ flat bones

❏ sesamoid bone

❏ short bones

❏ irregular bone

Quiz!Can you identify what type of bones these are?

❏ flat bones

❏ sesamoid bone

❏ short bones

❏ irregular bone

Quiz!Can you identify what type of bones these are?

❏ flat bones

❏ sesamoid bone

❏ short bones

❏ irregular bone

Your bones are living tissue!

They are continually remodeling and changing shape in response to the bodies needs.

Living Tissue

Osteo = bone, cyte = cell

Osteoblasts – secrete a matrix made up of calcium phosphate crystals. “Blasts Build up Bone”.

Osteocytes – retired osteoblasts; found within bony wall that they have deposited around themselves.

Osteoclasts – break down bone; release acids to dissolve crystals and enzymes to break down matrix. “Clasts Chew Bone”.

Bone Remodeling

▪Goes on throughout life▪10-30% of adult bone is re-built every year

▪Bones of femur completely rebuilt every 6 months

▪Bones in skull may take 10 years to re-build

▪Drink your milk (and sunshine for vitamin D)

Bone Remodeling Fun Facts

Wolff’s Law: Greater physical stress placed on a bone at a particular site results in more bone deposition by osteoblasts at that site

Examples: Astronauts who spend a

long time in space will often return to Earth with weaker bones, since gravity hasn't been exerting a load on their bones. Their bodies have reabsorbed much of the mineral that was previously in their bones

Weightlifters often display increases in bone density in response to their training.

Bone Reacts to Stresses Put on It

• Lever components•Fulcrum- joint•Resistance- weight•Effort- muscle

• First class lever•Fulcrum is between effort and resistance

• Second class lever•Resistance is between effort and fulcrum

• Third class lever•Effort is between the fulcrum and resistance

Levers in the Body

F

E R

Biceps brachii musclesConnects scapula to radiusElbow joint is made of the junction of humerus and radius and ulnaActs to flex the elbow joint (reduce the flexion angle)

What type of lever?

Third class lever!F

E

R

Gastrocnemius and other caudal leg musclesConnects femur to calcaneus bone of footFulcrum is the digital joints of the footAct to extend (increase the flexion angle of) the tarsal (ankle) joint and flex (decrease the flexion angle of) the digital joints

What type of lever?

E

R

F

Second class lever!

Triceps muscleConnects scapula to ulnaElbow joint is made of the junction of humerus and radius and ulnaAct to extend (increase the flexion angle of) the elbow joint

What type of lever?

First class lever!E

RF

The weight lifting problem

How much force does your biceps have to apply to keep the ball in place?

Force and Torques

Force and Torques

Find the pivot point

Find the direction of the forces

Find the distances from each center of mass to the pivot point

d2

d3

d1

Force and Torques

W1

M1 is the weight of the ballM2 is the weight of the forearm

W2

d3

d2

d1

W1 is the weight of the ballW2 is the weight of the forearm

Why does the biceps work so hard to lift a combined 23lbs?

The biceps does not get much benefit from the lever and fulcrum because its attachment is close to the pivot and the resistance is far from both pivot and biceps.

Force and Torques

W1

W1= 20lb d1= 30cmW2= 3lb d2= 30/2cm

d3= 2.5cm

How much force does the biceps exert to keep a 20lb ball in place?

W2

d3

d2

d1

FRACTURESA medical condition in which there is a break in the continuity of the

bone.

What is a radiograph?Radiographs are:• The image produced on a film by X-rays or other forms of radiation.

X-Rays are:• Electromagnetic radiation of short wavelength produced when high-speed

electrons strike a solid target.

X-Rays produced here!

X-Rays travel here!

X-Ray film here!

Radiograph FAQ’s!Does it hurt the animal?• Not at all! They are totally painless, you cannot see or feel the X-Rays!

Are they safe?• Yes, the dose of radiation used is the smallest possible to make a diagnostic

image.

• Anyone regularly working around X-Rays must wear a dosimeter that tracks their total exposure.

Name The Animal!

What Did the Snake Eat?

Human Vs. Dog

Normal Dog Images!

Can you name the breed of the dog?

Boxer

Closed Fracture▪ A broken bone that

does not penetrate the skin.

▪ Also known as a simple fracture.

Open Fracture

▪ A broken bone that penetrates the skin.

▪ Also known as a compound fracture.

▪ Needs immediate treatment, and an operation is often required to clean the area of the fracture.

▪ Higher risk of infection and more problems associated with healing.

Normal Fracture Healing

White zone is area of new bone deposit

Mal-union – a fracture that heals with abnormal alignment

Non-union – fracture healing has STOPPED before the bone is completely healed

elephant foot “hypertrophic non-union” tapered “atrophic non-union”

Osteomyelitis – infection of bone

Abnormal Fracture Healing

Malunion

In the wrist In the elbow

Mal-union – a fracture that heals with abnormal alignment

Non-union Hypertrophic non-union is a bulging

appearance at the fracture site, which results from a large amount of callus formation. Usually caused by too much mobility at fracture site, blood supply is adequate.

Atrophic non-union is narrow, rounded ends of bone at the level of the fracture. This is caused by a poor healing response due to a lack of blood supply.

Osteomyelitis

Osteomyelitis – infection of bone

What species is this?Horse- it only has one toe

▪Get bones close enough together to heal correctly

▪Proper alignment

▪ To Avoid:▪ mal-union ▪ loss of function▪ additional trauma▪ further fracture▪ infection

Fracture Reduction Goals

Fracture Reduction

▪Closed fractures▪ Permanent (cast or splint)▪ Temporary (until surgery)

▪Open fractures (orthopedic surgery)▪Intramedullary Fixation (Pins)

▪Cerclage (Wires)

▪External Fixation Devices

Treatment Options

Closed Fracture Reduction

Use of a bandage or splint to heal the fracture. Can be

temporary or permanent.

Open Fracture Reduction

An open fracture reduction involves cutting through the skin to realign the

bones. Normally this is used if the bone is in

many pieces or is difficult to reduce.

Intramedullary Fixation

Intramedullary fixation is the use of pins, they come in a variety of sizes. You pick the pin based upon the bone itself, the animal, and the location.

Cerclage

Cerclage: encircling the bone with a wire ring or loop, as for fixation of fragments in a fractured bone

External Fixators The process of

installing temporary repair supports

outside of the skin to stabilize and align

bone while the body heals.

External Fixators

Surgery Tools

▪ Animal Orthopedics as a Human Model

▪ Animals are used as human models in clinical studies or experiments in the development of surgical procedures & drugs in veterinary medicine to be used in human medicine.

▪ Example:▪ The 1st hip

replacement surgery was developed in military dogs (German Shepherds have a genetic problem with hip joint being misaligned).

Protect Yourself

▪ Osteoporosis is a bone disease where the bone mineral density is reduced.

▪ Bones become much more fragile. People with osteoporosis are more likely to suffer fractures than people with normal bone density.

▪ Reaching peak bone mass when young greatly reduces your risk of developing the disease.

▪Physicians recommend that adolescents get 30 minutes of exercise everyday of the week.

▪Be sure children and teens are getting the recommended 1300 mg of calcium a day.

▪Eating a balanced diet and exercising will keep you agile, make you strong, and reduce your risk of developing many serious diseases later in your life.

How to Strengthen Your Bones

▪Osteoarthritis is deterioration or loss of the cartilage that acts as a protective cushion between bones, particularly in weight-bearing joints such as the knees and hips.

▪Treatment: Injection of anti-inflammatory drugs into arthritic joints reduces inflammation and pain.

▪Problem?: Drug effect doesn’t last, because drug diffuses out of the joint quickly. Effect could last longer if drug were held in the joint.

Current NIH ResearchTopic: Sustained-Release Drug Carrier for Treatment of Osteoarthritis

▪Researcher Lori A. Setton at Duke University designed a protein to inject along with the drug.

▪This modified and injectable arthritis drug remains at the site of the injection and forms a “drug depot”.

▪When studied in a rat knee joint model, the delivered protein/drug combination remained in the joint 25 times longer than the comparable soluble drug on the current market.

Solution

▪Today we learned:▪What is orthopedics?

▪What are bones?

▪How to classify bones

▪Types of levers

▪Muscle forces

▪Fractures!

▪How to repair a fracture

▪A quick look at current research involving bones

▪All of this information is true for people and pets!

What we have covered!

Bone Density and Fractures Lab

Materials Good long bones to use include

the humerus, radius, femur, or tibia

Choose bones from a mammal not a bird

Bones should be sawed into transverse pieces small enough to fit in your graduated cylinders

Bones should be boiled before use Try asking a local slaughterhouse

or butcher for bones Use balances with decimal points

and graduated cylinders with 1 mL marks for best accuracy

Main points Long bones are less dense at the

ends than in the middle Physeal plates where bone growth

occurs are near the ends of the bone

More spongy bone is found at the ends

More compact bone is found near the center

Spongy bone is less dense than compact bone

Fractures are more likely to occur near the ends of the bone than in the middle

Reminders for students Density=Mass/Volume Don’t round until the end Measure mass before volume so that

the bone specimens won’t be wet Record initial and final volume to

calculate water displacement volume

Charts and Graphs