What are we going to learn? ▪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! Orthopedics Defined 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 Associated Structures ▪ 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 What Do Bones Do? 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 Anatomy of a Typical Bone 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 Classification of Bones ▪ 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. 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 Living Tissue Your bones are living tissue! They are continually remodeling and changing shape in response to the bodies needs. Bone Remodeling 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 Fun Facts ▪ 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 Reacts to Stresses Put on It 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. Levers in the Body • Lever components •Fulcrum- joint •Resistance- weight •Effort- muscle E • First class lever •Fulcrum is between effort and resistance R F • Second class lever •Resistance is between effort and fulcrum • Third class lever •Effort is between the fulcrum and resistance What type of lever? Biceps brachii muscles Connects scapula to radius Elbow joint is made of the junction of humerus and radius and ulna Acts to flex the elbow joint (reduce the flexion angle) E F R What type of lever? Gastrocnemius and other caudal leg muscles Connects femur to calcaneus bone of foot Fulcrum is the digital joints of the foot Act to extend (increase the flexion angle of) the tarsal (ankle) joint and flex (decrease the flexion angle of) the digital joints E R F What type of lever? Triceps muscle Connects scapula to ulna Elbow joint is made of the junction of humerus and radius and ulna Act to extend (increase the flexion angle of) the elbow joint E F R Force and Torques The weight lifting problem How much force does your biceps have to apply to keep the ball in place? Force and Torques ∑𝑻𝒐 = 𝟎 Find the pivot point Find the direction of the forces Find the distances from each center of mass to the pivot point d3 d2 d1 Force and Torques ∑𝑇𝑜 = 0 M W11 is is the the weight weight of of the the ball ball M W22 is is the the weight weight of of the the forearm forearm 𝑇 =𝐹∗𝑑 W2 W1 ⊥ 0 = 𝑀1 ∗ 𝑑1 + 𝑀2 ∗ 𝑑2 − 𝐹 ∗ 𝑑3 0 = 𝑇1 + 𝑇2 + 𝑇3 𝐹 ∗𝑊𝑑13∗=𝑑1𝑀+1 𝑊 ∗ 𝑑21∗+𝑑2𝑀−2 ∗𝐹𝑑∗2𝑑3 0= d3 d2 𝐹= 𝑑22)/𝑑 ∗ 𝑑(𝑀 𝑊𝑑11∗+𝑑𝑀 ∗ 𝑑23 1∗ 2 ∗𝑊 3 = 1+ d1 𝐹 = (𝑊1 ∗ 𝑑1 + 𝑊2 ∗ 𝑑2)/𝑑3 Force and Torques W2 W1 d3 d2 d1 W1= 20lb 𝑭 = 𝟐𝟓𝟖𝒍𝒃 d1= 30cm W2= 3lb d2= 30/2cm Why does the bicepsd3work = 2.5cm so hard to lift a combined 23lbs? 𝐹 = (𝑊1 ∗ 𝑑1 + 𝑊2 ∗ 𝑑2)/𝑑3 The biceps does not get much 𝐹 = (20𝑙𝑏 ∗ 30𝑐𝑚 3𝑙𝑏 ∗ and 15𝑐𝑚)/2.5𝑐𝑚 benefit from the +lever fulcrum because its attachment is close to How much force does the biceps exert to the pivot and the resistance is far keep a 20lb ball in place? from both pivot and biceps. FRACTURES A 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 Abnormal Fracture Healing 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 Malunion In the wrist Mal-union – a fracture that heals with abnormal alignment In the elbow 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 Fracture Reduction Goals ▪Get bones close enough together to heal correctly ▪Proper alignment ▪ To Avoid: ▪ ▪ ▪ ▪ ▪ mal-union loss of function additional trauma further fracture infection Treatment Options Fracture Reduction ▪Closed fractures ▪ ▪ Permanent (cast or splint) Temporary (until surgery) ▪Open fractures (orthopedic surgery) ▪ Intramedullary Fixation (Pins) ▪ Cerclage (Wires) ▪ External Fixation Devices 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. How to Strengthen Your Bones ▪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. Current NIH Research Topic: Sustained-Release Drug Carrier for Treatment of Osteoarthritis ▪ Osteoarthritis is deterioration or loss of the cartilage that acts as a protective cushion between bones, particularly in weightbearing joints such as the knees and hips. ▪ Treatment: Injection of antiinflammatory 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. Solution ▪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. What we have covered! ▪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! 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 Charts and Graphs 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