Session 4-Bones And Joints Flashcards
What are the functions of the skeleton? (5)
1) Support
2) Protection
3) Movement
4) Mineral and growth factor storage
5) Haematopoesis
Bone is the primary site of storage for which growth factor?
Insulin-like growth factor
True or false: long bone is primarily compact bone but may have spongy bone at extremities
TRUE
What is the articular cartilage of long bone covered in?
Hyaline
Why is the medullary cavity of long bone red in children?
Haematopoesis is occurring
Give an example of a long bone
Femur
How do muscles act on long bone?
As rigid levers
Give an example of sesamoid bone
Patella
What are sesamoid bones embedded within?
Tendon or muscle
Give examples of short bones
Carpal and tarsal bones
What do short, flat and sesamoid bones consist of?
Spongy bone in between thin layer of compact bone
True or false: short, flat and sesamoid bones contain bone marrow between the trabeculae of compact bone
FALSE - between spongy bone
How does the nutrient artery enter the diaphysis of bone?
Via nutrient foramen
What do periosteal arteries supply?
Periosteum and outer third of cortex
Where do metaphyseal arteries enter the metaphysis?
At site of attachment of capsule
What is avascular necrosis?
Death of bone due to interruption of blood supply
What are the other names for avascular necrosis?
Osteonecrosis
Aseptic necrosis
Ischaemic necrosis
What are the causes of avascular necrosis? (5)
Fracture Dislocation Steroid use Radiation Decompression sickness
What can avascular necrosis lead to?
Collapse of necrotic segment and secondary osteoarthritis
What is a joint?
Articulation between two or more bones
What are the three structural classifications of joints?
1) fibrous
2) cartilaginous
3) synovial
Where can fibrous joints be found?
Sutures of skull
Inferior tibiofibular joint
Radioulnar interosseus membrane
Joint between roots of teeth and bone of mandible/maxilla
What is a primary cartilaginous joint and give examples?
United by hyaline cartilage
1st sternocostal joint
Xiphisternal joint
Epiphyseal growth plates of long bones
What is a secondary cartilaginous joint and give examples?
Articulating bones covered with hyaline cartilage with pad of fibrocartilage between them
Symphysis pubis
Intervertebral disc
Manubriosternal joint
What is contained within the joint cavity of a synovial joint?
Synovial fluid
What are the characteristics of synovial joints? (4)
1) articular cartilage
2) fibrous capsule
3) synovial membrane
4) synovial fluid
What is the typical articular cartilage type in synovial joints? What are the exceptions?
Hyaline cartilage
Acromioclavicular, sternoclavicular and temporomandibular joints are atypical synovial joints covered in fibrocartilage
How does hyaline cartilage resist compression?
By acting as a shock absorber
What is the fibrous capsule of synovial joints made of?
Collagen, which completely encloses the joint except where it is interrupted by synovial protrusions
How does the fibrous capsule of synovial joints stabilise the joint?
Permits movement but resists dislocation
True or false: synovial membrane does not cover articular cartilage or intra-articular discs/menisci
TRUE
What is a bursa?
Sac lined with synovial membrane and filled with synovial fluid. It is a cushion between bones and tendons or muscles around a joint-it reduces friction and allows free movement
What is a tendon sheath?
Elongated bursa wrapped around a tendon which reduces friction
Describe synovial fluid
Clear or pale yellow
Viscous
Slightly alkaline at rest
What is synovial fluid composed of?
Hyaluronic acid
Lubricin
Proteinase
Collagenase
What are the functions of synovial fluid? (3)
1) Reduces friction
2) Shock absorption
3) Nutrient and waste transportation
True or false: articular cartilage of synovial joints is avascular
TRUE
True or false: synovial membrane has rich blood supply
TRUE
What is Hilton’s law?
Nerves supplying joint capsule also supply muscles moving the joint and the skin overlying the insertions of these muscles
What are the six types of synovial joint?
1) planar joint
2) hinge joint
3) ball and socket joint
4) condyloid joint
5) saddle joint
6) pivot joint
Give examples of a planar joint
Sternoclavicular joint
Acromioclavicular joint
Intercarpal joints
What is the range of motion of a planar joint?
Non-axial, gliding and sliding movements
Give examples of a hinge joint
Knee
Ankle
Humeroulnar joint of elbow
What is the range of movement of a hinge joint?
Uniaxial/monaxial
What is the shape of a hinge joint?
Pulley-shaped: convex surface of one bone fits into concave surface of another
Give examples of a pivot joint
Proximal radioulnar joint
Atlantoaxial joint
What is the range of motion of a pivot joint?
Uniaxial/monaxial joint
What is the shape of a pivot joint?
Rounded or pointed surface of one bone articulates within ring formed by concavity of another bone and fibrous ligament
What is another name for a condyloid joint?
Ellipsoidal
Give examples of a condyloid joint
Metacarpophalangeal joints
Radiocarpal joint
Atlanto-occipital joint
What type of joint is a condyloid joint?
Biaxial joint
Which movements can a condyloid joint allow?
Flexion Extension Abduction Adduction Circumduction
What type of joint is a saddle joint?
Biaxial joint
Give an example of a saddle joint
1st carpometacarpal joint
Which movements does a saddle joint allow?
Flexion Extension Abduction Adduction Circumduction
What type of joint is a ball and socket joint?
Multiaxial/polyaxial
Which movements does a ball and socket joint allow?
Flexion Extension Abduction Adduction Circumduction Rotation
Give examples of a ball and socket joint
Hip
Shoulder
Incudostapedial joint (middle ear)
Which factors affect the stability and range of motion at synovial joints? (6)
1) structure/shape of articulating bones
2) strength and tension of joint ligaments
3) arrangement and tone of muscles
4) apposition of neighbouring soft tissues
5) hormones
6) use/disuse
True or false: the greater the range of movement, the more stable the joint is
FALSE - less stable
What is the theory behind joint cracking? (6)
1) bones pulled away from each other
2) synovial cavity expands
3) synovial flood volume stays constant
4) partial vacuum produced
5) gases dissolved in synovial fluid are pulled out of solution
6) makes popping sound
What is the effect of ageing on joints? (3)
1) decreased production of synovial fluid
2) thinning of articular cartilage
3) shortening of ligaments and decreased flexibility
What are the symptoms of arthritis?
Pain
Swelling
Stiffness
What are the signs of arthritis?
Redness Swelling Deformity Tenderness Reduced range of movement (ROM) Abnormal gait
What happens in rheumatoid arthritis?
Autoantibodies attack the synovium -> synovial inflammation
Which joints are most commonly affected in rheumatoid arthritis?
MCP and PIP joints of hands
Cervical spine
Feet
Which other organs are damaged by rheumatoid arthritis?
Eyes Skin Lungs Heart and blood vessels Kidneys
What is the peak age of rheumatoid arthritis?
40-50 years
What are the x-ray features of rheumatoid arthritis? (4)
1) narrowing of joint space
2) periarticular osteopenia (loss of bone substance adjacent to joint)
3) juxta-articular bony erosions
4) subluxation (partial dislocation) and gross deformity