Joints

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Joints

• Skeletal System

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Joints
Greek root arthro means join

• Rigid elements of the skeleton meet at joints or
  articulations
• Articulations can be
• Bone to bone
• Bone to cartilage
• Function
• To hold bones together
• To allow mobility
• To resist bone crushing, tearing, and other
  forces

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Classifications of Joints

• Joints can be classified in 2 ways
• Function based on amount of movement
• Synarthroses immovable usually in the axial
  skeleton (trunk)
• Amphiarthroses slightly movable usually in the
  axial skeleton (trunk
• Diarthroses freely movable usually in the
  appendicular skeleton (limbs)
• Structure based on material that binds bones
  together
• Fibrous
• Cartilaginous
• Synovial

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A Typical Synovial Joint

• Synovial joints are joints that DO contain a
  joint cavity
• They are freely moveable (diarthroses)
• They also contain their own lubricating devices
• They are subjected to compressive forces
• More so than any other type of joint in the body

Articular (hyaline) cartilage covers the ends of
the bone
Synovial Membrane is a smooth layer of tissue
that lines joints
Synovial Fluid is a lubricating fluid that lies
in the joint cavity
Articular (hyaline) cartilage covers the ends of
the bone
Ligaments are a cord of elastic fibrous tissue
that link bones
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Fibrous Joints

• Bones are sometimes connected by fibrous
  connective tissue
• These DO NOT have a joint cavity
• Most are immovable (synarthroses)
• Ex Suture
• Only occur between the bones of the skull (short
  fibers)
• Allow bone growth so the skull can expand with
  brain during childhood

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Cartilaginous Joints

• Bones are united by cartilage
• DO NOT have a joint cavity
• Joints are only slightly moveable (amphiarthoses)
• Ex Symphyses
• Cartilage located between the vertebrae
• Ex Synchondroses
• Cartilage located in the epiphyseal plate

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Tendons
Tendonitis is the overuse of the tendons, which
can cause a great deal of pain upon movement

• Tendons are structures that connect bone to
  muscle and are made up of tendon tissue
• Typical shape is a cord-like tendon of the biceps
• As muscles contract or flex the tendons
  followand move bones

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Ligaments

• Ligaments
• Connect bone-to-bone
• Reinforce joints
• They are made up of tendon tissue as well
• E.g. knee ligaments

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Bursae

• Bursae are not really part of synovial joint
  structure
• However, they are very important
• They are essentially bags of lubricant
• They reduce friction as they contain a thin film
  of synovial fluid

Bursitis is known as inflammation of the Bursae
(water swelling)
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Joint Injuries - Sprains

• The ligaments reinforcing a joint are stretched
  or torn
• Partially torn ligaments slowly repair themselves
• This is due to a lack of blood flow
• Completely torn ligaments require surgical repair

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Joint Injuries - Dislocations

• Occur when bones are forced out of alignment
• Usually accompanied by sprains, inflammation, and
  joint immobilization
• Caused by serious falls and are common sports
  injuries
• Tractions (pressure) are usually required to
  place the bone back into its joint

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Arthritis

• Arthritis inflammation of the joints
• Over 200 forms of arthritis, but most occur in
  synovial joints
• About 30 of adults have arthritis.
• Major symptom is PAIN in or around joints
• Acute (non-threatening) forms are caused by
  bacteria and are treated with antibiotics
• Risks
• Age gt 40 years, Women gt men, Obesity

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Osteoarthritis (OA)

• Breakdown in cartilage and bone (this is the
  chronic form of arthritis)
• 21 million Americans have osteoarthritis
• Increased risk with older age, obesity, overuse
  or previous injury to joints
• Common spots of Osteoarthritis
• hips
• knees
• hands
• base of big toe
• spine

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X-ray of hand affected by arthritis
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Gouty Arthritis

• Uric acid crystals build up in joints
• Genetically passed down..
• But can also be occur due to a purine-rich diet
  (alcohol, meats, liver, scallops)
• This is followed by inflammation
• Typically, gouty arthritis affects the joint of
  the big toe
• In untreated gouty arthritis, the bone ends fuse
  and immobilize the joint

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Arthritis Treatments

• OA is slow and irreversible
• Meaningthere is no cure ?
• Treatments include
• Mild pain relievers, along with moderate exercise
• Glucosamine sulfate decreases pain and
  inflammation
• You can buy this in stores (it is an amino acid)