The Skeletal System

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The Skeletal System

• Lindsey Bily
• Austin High School
• Anatomy Physiology
• Ch. 7, 8 9 in your textbook

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Types of Bone

• Compact Bone Dense or solid in appearance.
• Cancellous (Spongy) Bone has open spaces (looks
  like a sponge, wow, I wonder how they came up
  with that name?)
• The 4 types of bone have different amounts of
  compact and cancellous bone.

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Long Bones

• They are long, hence the name.
• Examples Humerus and femur

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Short Bones

• They are cube or box-shaped.
• Examples Carpals in the wrist and tarsals in the
  ankle

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Flat Bones

• Broad and thin with a flattened and often curved
  surface.
• Examples certain skull bones, sternum, scapulae,
  ribs

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Irregular Bones

• Usually found in groups and come in various sizes
  and shapes. Thats why they are called IRREGULAR.
• Examples vertebrae, facial bones.

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Parts of the Long Bone

• 1. Diaphysis (di-AF-i-sis) main portion that is
  hollow, cylindrical and is composed of compact
  bone.
• 2. Epiphyses (e-PIF-i-sis) at both ends of the
  long bone, they have a bulbous shape and are
  composed of spongy bone. The spongy bone
  contains red bone marrow.
• 3. Articular Cartilage thin layer of hyaline
  cartilage that covers the joint surfaces of the
  epiphyses. Cushions jolts and blows.
• 4. Periosteum (pair-ee-OS-tee-um) membrane that
  covers the bone (contains bone forming and bone
  destroying cells and blood vessels).
• 5. Medullary (marrow) cavity tubelike, hollow
  space in the diaphysis that contains yellow
  marrow in adults.
• 6. Endosteum (end-OS-tee-um) A thin epithelial
  membrane that lines the medullary cavity.

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Parts of the Long Bone
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Bone (Osseous) Tissue

• Bones have an Inorganic and an Organic Matrix.
• Inorganic Matrix
• Bones are calcified (contain calcium phosphate
  (Ca3(PO4)2) which is why they are hard and so
  strong.
• Magnesium, sodium, sulfate, and fluoride are also
  found in bone.

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Bone (Osseous) Tissue

• Organic Matrix
• Ground Substance composed of collagenous fibers,
  protein, and polysaccharides.
• Chondroitin sulfate and glucosamine are required
  for repair and maintenance of bone and cartilage.
  People take it to treat arthritis pain.

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Compact Bone Microscopic Level

• Remember OSTEONS? Theyre baaaa-aaaack
• Osteons are also called Haversian systems, who
  discovered them.
• They are cylindrically shaped structural units of
  bone.
• The structure of the osteons allows for the
  delivery of nutrients and the removal of waste
  from the bone cells that are imprisoned in bone.
  

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Osteons

• There are no empty spaces in compact bone, it is
  made up of lots of osteons (Haversian System).
• Each ring is called a concentric lamella and
  resemble rings in an onion.
• These surround the Haversian canal, which contain
  blood vessels.
• Osteocytes are bone cells
• Nutrients pass from the blood vessel in the
  Haversian canal through canaliculi, tiny passages
  or canals, to osteocytes located in little spaces
  called lacunae.

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Osteons
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Cancellous Bone Microscopic Level

• No osteons in cancellous (spongy) bone.
• Consists of needle-like bony spikes called
  trabeculae.
• Bone cells are found in the trabeculae.
• Spongy bone lies between two layers of compact
  bone like an Oreo cookie.
• The trabeculae are organized so that they are
  able to handle the stress that is put on the bone
  so that the bone is stronger.

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Cancellous Bone
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Bone
A Spongy Bone B Compact Bone C Medullary Cavity
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Bone Cells

• Three major types found in bone
• Osteoblasts (bone-forming cells)
• They are small and make osteoid which is in the
  ground substance of bone which then can absorb
  calcium and phosphate.
• Osteoclasts (bone-reabsorbing cells)
• They are giant cells and have multiple nuclei and
  they erode the bone minerals. They contain lots
  of lysosomes and mitochondria.
• Osteocytes (mature bone cells)
• They are nondividing osteoblasts that are
  surrounded by bone and lie in the lacunae.

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Osteoblasts
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Osteoclasts
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Osteocytes

• Since osteocytes are surrounded by bone, they
  must have a way to get nutrients. They have
  projections that extend into the canaliculus in
  the bone that allows them to get nutrients.

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Bone Marrow

• This is where blood cells are made and is found
  in the medullary cavities of certain long bones
  in and the spaces of spongy bone in some areas.
• In the infant and child, virtually all marrow is
  red marrow. It produces red blood cells.
• As we age, the red marrow is replaced by yellow
  marrow which contains lots of fat and does not
  produce red blood cells.
• Bones in the adult that still contain red marrow
  are the ribs, vertebrae, ends of the humerus,
  pelvis, and femur.

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Bone Marrow

• If we have a low blood supply due to injury,
  exposure to radiation or toxic chemicals and
  certain diseases the yellow marrow will change to
  red marrow.
• A bone marrow transplant may be required if the
  marrow is severely damaged.
• Healthy bone marrow from a compatible donor is
  injected into the blood and if the recipients
  immune system doesnt reject it, new, healthy
  bone marrow can grow.

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Functions of Bone

• Support
• Protection
• Movement
• Mineral Storage
• Bones store calcium, phosphorus, magnesium,
  fluoride, etc
• Hematopoiesis
• Blood cell formation done in the red marrow in
  the epiphyses of long bones, flat bones of the
  skull, pelvis, sternum, and ribs.

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Regulation of Calcium Blood Levels

• Bones store 98 of the bodys calcium reserves
• We need a certain level of calcium in our blood
  in order for our muscles to contract, heart to
  pump, blood to clot and nerves to fire.
• Calcium moves in and out of the bone into the
  blood to maintain homeostasis.
• Osteoblasts take calcium out of blood and into
  bone.
• Osteoclasts take calcium out of bone and into the
  blood.

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Regulation of Blood Calcium Levels

• Parathyroid Hormone (PTH)
• Released by the parathyroid glands which lie on
  the thyroid gland in your neck.
• When calcium levels are LOW, parathyroid hormone
  is released which stimulates the osteoclasts to
  break down bone and release calcium into the
  blood.
• PTH also increases calcium absorption from the
  urine and stimulates Vitamin D synthesis which
  stimulates the intestines to absorb calcium more
  efficiently.

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Regulation of Blood Calcium Levels

• Calcitonin
• Hormone released by the THYROID gland
• When blood calcium levels are too HIGH,
  calcitonin is released.
• Calcitonin stimulates the osteoblasts and
  inhibits the osteoclasts so that calcium is taken
  out of the blood and put into the bone.
• http//bcs.whfreeman.com/thelifewire/content/chp42
  /4202003.html

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Development of Bone

• When the skeleton begins to form it is made of
  cartilage shaped like bones. Over time the bones
  calcify.
• Osteogenesis (osteo-bone genesis creation)
  is when the cartilage undergoes calcification.

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Growing Taller

• As a person is growing, there is a line of
  cartilage in between the epiphysis and the
  diaphysis in the long bones called the epiphyseal
  plate.
• You grow taller when the plate grows bigger, then
  becomes ossified.
• Once a person is no longer growing taller, the
  plate totally ossifies.

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Bone Fractures

• Fracture is a break in the bone.
• Open or Compound Fracture the broken bone goes
  through the surrounding tissue and skin. Risk of
  infection is high.
• Closed or Simple Fracture does not produce a
  break in the skin.
• Complete Fracture break across the entire
  section of bone.
• Incomplete Fracture partial break in the bone

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Bone Fractures
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Bone Disorders Diseases

• Neoplasms (new growth)
• Osteochondroma tumor that develops early in life
  and causes projections (spurs) at the ends of the
  long bones. Usually they are benign but
  sometimes can become cancer.
• Osteosarcoma malignant tumor in the bone tissue
  that is the most fatal. Almost 10 of patients
  grow tumors in the lungs and other organs.
• Chondrosarcoma malignant tumor in the hyaline
  cartilage. Slow growing and occurs most often in
  middle aged people. Chemotherapy usually doesnt
  work, so amputation of the affected area usually
  occurs.

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Bone Disorders Diseases

• Osteoporosis Excessive loss of calcified matrix,
  minerals, and collagen fibers. Bones become
  porous, brittle and fragile. They can fracture
  easily.
• Pagets disease Have a lot of osteoclast growth
  which in turn will cause the body to produce more
  osteoblasts. Since there are so many bone cells,
  the remodeling process is too rapid and
  disorganized. The bones are poorly made and
  weakened. Sometimes patients feel pain in their
  bones and may have fractures, but most people
  dont have symptoms
• Osteomylelitis Bacterial, fungal or viral
  infection of the bone and bone marrow. Usually
  associated with another infection.

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The Skeleton

• Terms used to describe bone markings
• Condyle rounded bump that usually fits into the
  fossa on another bone, forming a joint
• Foramen round hole in bone that allows vessels
  and nerves to go through.
• Fossa depression in the bone that often receives
  an articular bone.
• Meatus tubelike opening or channel
• Process a raised area or projection
• Sinus cavity within a bone
• Trochanter Large bump on bone for muscle
  attachment
• Tuberosity smaller than a trochanter and a bump
  for muscle attachment

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The Skeleton

• The human skeleton is composed of 206 bones and
  divided into two sections.
• Axial Skeleton
• Appendicular Skeleton

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The Axial Skeleton

• Composed of the bones of the
• Skull
• Hyoid Bone
• Vertebral Column
• Sternum
• Ribs

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The Skull

• Composed of 28 irregular bones
• Divided into two sections
• Cranium
• Face

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Cranial Bones

• Sutures are where 2 cranial bones fuse together.
• Frontal Bone (forehead)
• Contains sinuses which are lined with mucous
  membranes and filled with air.
• Parietal Bones
• There are two on both upper sides of your head.
  Fuse with the frontal bone.
• Temporal Bones
• there are two on the lower sides of your head.
  They house the middle and inner ear

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Cranial Bones

• Occipital Bone
• There is one at the lower, posterior part of your
  skull.
• Sphenoid Bone
• Looks like a bat with its wings outstretched.

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The Cribiform Plate

• This is a part of the ethmoid bone that separates
  the nasal from the cranial cavities.
• It has many small holes in it so that the
  olfactory nerve can go from the nose to the
  brain.
• It is very dangerous though because infections in
  the nose and nasal cavities can have a tendency
  to reach the brain.
• Also, if the cribiform plate is fractured, shards
  of bone may enter the brain.

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Facial Bones

• Bones you need to know
• Maxillae
• Mandible (jaw bone)
• Zygomatic bone (the cheekbone)
• Nasal bones

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Hyoid Bone

• A single bone in the neck.
• It is the only bone in the body that does not
  articulate (touch) another bone.
• U shaped and you can feel it just above the
  larynx (voice box)
• The tongue muscle and other mouth muscles attach
  to it.

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Vertebral Column

• The spinal column
• Flexible and segmented
• Consists of 24 vertebrae and the sacrum and
  coccyx
• The head is balanced on the top
• The ribs are suspended in the front
• The lower extremities are attached below
• The spinal cord is enclosed within.

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Vertebral Column

• The vertebrae are separated into divisions
• 7 cervical vertebrae
• 12 thoracic vertebrae
• 5 lumbar vertebrae (includes the sacrum and the
  coccyx)

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Atlas and Axis

• Atlas first cervical vertebra (C1)
• Has concave ovals that the condyles of the
  occipital bone fit on like a rocker-like cradle.
• Named Atlas after the titan in Greek mythology
  because it supports the head as Atlas supports
  the world.
• Axis 2nd cervical vertebra (C2)
• Named the axis because the atlas rotates about on
  it like a pivot.

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Sternum and Ribs

• Top of the sternum is called the manubrium.
• The first 7 ribs attach to the sternum. Called
  True Ribs
• The remaining 5 ribs dont attach to the sternum
  and are called False Ribs
• The last two pairs of False Ribs do not attach
  and are called Floating Ribs

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The Appendicular Skeleton

• Upper Extremity
• The shoulder girdle is composed of the clavicle
  and scapula
• i.e. the collarbone and the shoulder blades
• The Arms are composed of the humerus, radius and
  ulna.
• Humerus upper arm
• Radius on the thumb side when in anatomical
  position.
• Ulna on the pinky side when in anatomical
  position
• The Hand
• Carpals the bones of the wrist
• Metacarpals bones of the hand
• Phalanges fingers

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The Appendicular Skeleton
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The Appendicular Skeleton

• Lower Extremity
• Includes bones of the hip, thigh, lower leg,
  ankle and foot.
• The pelvis is composed 2 coccal bones which are
  connected to the sacrum posteriorly and by the
  pubic symphysis anteriorly.

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The Appendicular Skeleton

• Femurs
• Thigh bones connected to the pelvis.
• Longest and heaviest bones in the body.
• Patella (kneecap)
• Lower leg bones
• Tibia the larger, and stronger bone. Is placed
  medially and superficially. Holds the bodys
  weight.
• The proximal end of the tibia articulates with
  the femur to form the knee joint.
• Fibula the smaller bone. Is placed laterally and
  deep.

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The Appendicular Skeleton

• The Foot
• Similar to the hand bones.
• Tarsals (ankle)
• Metatarsals ( foot bones)
• Phalanges (toes)

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Skeletal Differences Between Men and Women

• The male skeleton is larger and heavier.
• The male pelvis is deep and funnel shaped
• The female pelvis is shallow and broad.
• Skull
• Forehead in male is shorter
• The mandible and maxilla in the male are larger
• Facial area is more pronounced
• The processes (projections) are more prominent.

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Male vs. Female Pelvis
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Articulations

• Articulations are joints, which are points of
  contact between bones.
• Some allow a lot of movement, some are completely
  immovable.
• Can be named based on their functionality (degree
  of movement) or based on their structure (what
  type of connective tissue holds the bones
  together or if the joint has a fluid filled
  capsule)

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Primary Joint Classifications

• Synarthroses are Fibrous Joints that are
  immovable.
• Ex. Sutures of the skull
• Amphiarthroses are Cartilaginous Joints that are
  slightly movable.
• Ex. Symphysis Pubis
• Diarthroses are Synovial Joints that have a fluid
  filled capsule and are freely movable.
• Shoulder joint

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Synarthroses (Fibrous Joints)

• The bones that have synarthroses fit very closely
  together. Most of the joints are fixed.
• Syndesmoses (SIN-dez-MO-ses) joints where two
  ligaments (fibrous bands) connect two bones.
• Ex. Distal ends of the radius and ulna are joined
  together by the radioulnar interosseous ligament.
  
• Sutures found only in the skull. Fit together by
  teethlike projections that interlock. Sutures
  start out fibrous tissue, but then ossify in
  adults.
• Gomphoses (gom-FO-ses) unique joints that occur
  between the root of the tooth and the mandible
  and maxilla. The fibrous tissue between the
  tooths root and the bone is the periodontal
  membrane.

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Synarthroses (Fibrous Joints)

• Syndesmosis between radius and ulna
• Sutures on the skull
• Gomphosis

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Amphiarthroses (Cartilaginous Joints)

• Bones in these joints are joined together by
  either hyaline cartilage or fibrocartilage.
• These joints have very limited movement.
• Two Types
• Synchondroses have hyaline cartilage between the
  bones.
• Ex articulation between the ribs and the sternum
  and the epiphyseal plate is a temporary
  synchondrosis in growing people.
• Symphyses have fibrocartilage between the bones
  which is a pad or disk. Remember fibrocartilage
  is extremely tough so there is only slight
  movement.
• Ex symphysis pubis and the articulations between
  the bodies of the vertebrae.

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Amphiarthroses (Cartilaginous Joints)
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Diarthroses (Synovial Joints)

• Freely movable joints.
• Most mobile, most numerous, and most complex
  joints.
• Parts of the synovial joint
• 1. joint capsule- the periosteum of both bones
  forms a sleeve around them, connecting them to
  each other.
• 2. synovial membrane- the lining of the joint
  capsule and secretes synovial fluid which
  lubricates and nourishes the inner joint
  surfaces.
• 3. articular cartilage- hyaline cartilage that
  covers the epiphyses of each bone.
• 4. joint cavity- small space between the
  articulating bones
• 5. menisci (articular disks)- pads of
  fibrocartilage between the articulating ends of
  bones in some synovial joints. The knee joint
  contains two.
• 6. ligaments- strong cords of dense, white
  fibrous tissue that hold the two bones together
  reinforcing the joint.
• 7. bursa- closed pillowlike structure that are
  filled with synovial fluid and function to
  cushion the joint and facilitate the movement of
  tendon (connections between muscles and bones).
  Bursitis is inflammation of the bursa.

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General Structure of a Synovial Joint
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Types of Synovial Joints

• Synovial joints can be further grouped by their
  shape, which controls the movement they allow.
• Ball and socket joints, such as the shoulder and
  hip joints. These allow a wide range of movement.
  
• Condyloid joints (or ellipsoid), such as the
  thumb. A condyloid joint is where two bones fit
  together with an odd shape (e.g. an ellipse), and
  one bone is concave, the other convex. Some
  classifications make a distinction between
  condyloid and ellipsoid joints.
• Saddle joints, such as at the thumb (between the
  metacarpal and carpal). Saddle joints, which
  resemble a saddle, permit the same movements as
  the condyloid joints.
• Hinge joints, such as the elbow (between the
  humerus and the ulna). These joints act like a
  door hinge, allowing flexion and extension in
  just one plane.
• Pivot joints, such as the elbow (between the
  radius and the ulna). This is where one bone
  rotates about another.
• Gliding joints, such as in the carpals of the
  wrist. These joints allow a wide variety of
  movement, but not much distance.

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Types of Synovial Joints
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Representative Synovial Joints

• Humeroscapular Joint (shoulder joint)
• The joint between the head of the humerus and the
  glenoid cavity of the scapula.
• Shoulder muscles and tendons from a cufflike
  arrangement around the joint called the rotator
  cuff
• The joint is more mobile than stable. Injuries
  to the rotator cuff and dislocations are fairly
  common.

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Humeroscapular Joint
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Hip Joint

• The hip joint is first stable, secondly, mobile.
• The ball-like head of the femur fits into the
  cup-like shape of the acetabulum (socket) of the
  hip.

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Tibiofemoral Joint (Knee)

• Largest and one of the most complex and most
  injured joint.
• Condyles of the femur articulate with the flat
  upper surface of the tibia.
• This is an unstable arrangement, however there
  are numerous ligaments, tendons, and cartilages
  that stabilize it.
• 2 menisci (medial and lateral) attach to the flat
  top of the tibia and form a socket for the femur
  to fit.
• There are about 13 bursae that serve as pads
  around the joint. The largest is the prepatellar
  bursa on the front of the knee.
• Compared to the hip joint, the knee isnt well
  protected by muscle so generally it is the one
  that is injured by blows or sudden stops or
  turns. Athletes frequently tear the cartilage in
  their knee, the menisci.

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Tibiofemoral Joint (Knee)
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Types and Range of Movement at Synovial Joints

• The types of movements possible at a joint depend
  on the shapes of the articulating bones
  surfaces, the positions of the ligaments, tendons
  and nearby muscles.
• The 4 types of movements
• Angular
• Circular
• Gliding
• Special

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Angular Movements

• Flexion decreases the angle between articulating
  bones. It bends or folds one part on another
• Extension increases the angle between
  articulating bones. It returns a part from its
  flexed position to its anatomical position.
  Straightening or stretching.
• Plantar flexion pointing the toe
• Dorsiflexion flexing the foot
• Abduction moves a part away from the median
  plane of the body.
• Adduction moves a part toward the median plane.

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Angular Movements
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Circular Movements

• Rotation and circumduction
• Rotation Pivoting a bone on its own axis (ex.
  Shaking your head no)
• Circumduction moves a part so that the distal
  end moves in a circle. (ex. Doing arm circles)
• Supination and Pronation
• Supination turns the palm side up
• Pronation turns the palm side down

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Gliding Movements

• Simplest of all movements.
• The articulating bones move past each other, but
  there is no angular or circular movement.
• Ex the carpal and tarsal bones glide past each
  other.

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Special Movements

• Often unique or unusual movements that occur only
  in a very limited number of joints.
• Inversion and eversion inversion turns the foot
  inward and eversion turns it outward.
• Protraction and retraction protraction moves a
  part forward and retraction back.
• Elevation and depression elevation moves a part
  up and depression lowers a part.

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Noninflammatory Joint Disease

• Osteoarthritis or degenerative joint disease
• wear and tear deterioration of the articular
  cartilage and formation of new bone at the joint
  surfaces. The cartilage is no longer a shock
  absorber, bone spurs grow, and ligaments calcify.
  
• Occurs most often in the hips, lumbar spine and
  knee. weight bearing joints
• Can occur in the finger joints and inflammation
  can occur causing swelling deformities.
• No treatment of osteoarthritis is available but
  can control the pain and inflammation with
  NSAIDs, nonsteroidal anti-inflammatory drugs
  (Ibuprofen, aspirin, Celebrex or Vioxx). May need
  partial or full joint replacement.

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Noninflammatory Joint Disease
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Traumatic Injuries

• Dislocation when the articular surfaces of the
  bone are no longer in the correct place. Can have
  damage to nerves and blood vessels
• Athletes tend to get torn menisci. Symptoms are
  edema, pain, instability of the knee and limited
  motion.
• Surgeons use arthroscopic surgical procedures to
  see inside joints without having to open the
  joint cavity. A narrow tube with lenses and
  fiberoptic light is inserted into the joint and
  saline solution is injected into the synovial
  space that spreads the joint structures and
  allows them to see inside.
• Sprain injury to the ligament. Blood vessels may
  be ruptured, bruising and swelling occur.

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Inflammatory Joint Disease

• Arthritis
• Rheumatoid arthritis chronic and systematic
  inflammatory connective tissue disease.
• Juvenile rheumatoid arthritis more severe than
  the adult form. Destroys growth of cartilage and
  growth of long bones slow. More common in girls.
• Gouty arthritis metabolic disorder where excess
  blood levels of uric acid deposit as crystals
  within the synovial fluid of joints and other
  tissues. A drug called Allopurinol (Zyloprim)
  inhibits the synthesis of uric acid and is used
  as treatment.

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Inflammatory Joint Disease

• Top left Gouty arthritis
• Top right rheumatoid arthritis
• Bottom Juvenile rheumatoid arthritis

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