Bones and Joints Flashcards
how many bones are their in the skeleton
206
how many bones are in the upper limb
64
how many bones are in the lower limb
62
what are the functions of the skeleton (5)
support, protect, movement, mineral and growth storage, haematopoesis
where does haematopoesis take place in children
in the long bones like the tibia
where does haematopoesis take place in adults
pelvis, skull, vertebrae and sternum
what is the structure of long bones
- primarily compact bone with spongy bone at the extremities
- diaphysis, metaphysis and epiphysis
- articular cartilage at the edges
- periosteum layer
- medullary cavity
- epiphyseal growth plates
what is the medullary cavity and what colour is it?
the cavity in the middle of long bones which is red in children as its involved in haematopoesis but yellow in adults due to its fat content
what is the structure of short, flat and sesamoid bones
- consists mainly of spongy bone with a thin layer of periosteum covered compact bone on the outside
- no epiphysis or diaphysis
contains bone marrow between the trabeculae
give an example of
- short bone
- long bone
- sesamoid bone
- flat bone
- carpal bones
- femur
- patella
- skull
what are sesamoid bones
bones embedded within a tendon or muscle
what are the 4 arteries supplying the bone
- nutrient artery - enters the diaphysis via the nutrient foramen
- periosteal arteries - supplies the periosteum and outer 1/3 of the cortex
- metaphyseal arteries
- epiphyseal artery
what happens to the metaphyseal and epiphyseal arteries in adults
they from anatomoses once the epiphyseal growth plate fuses
give 4 causes of avascular necrosis
fracture, dislocation, radiation and steroid use
what is avascular necrosis
death of bone due to interruption of blood supply
which bone does avascular necrosis most commonly occur and why
femur. the arteries supplying the neck are often insufficient to sustain the bone and so fractures that disrupt these arteries cause the head to die.
why does avascular necrosis lead to secondary osteoarthritis
the cartilage breaks down
what is a joint
articulation between 2 or more bones
what are the 3 types of structural classification of joints
- fibrous
- cartilaginous
- synovial
where are fibrous joints found
- sutures of the skull
- inferior tibiofibular joint
- radioulnar interosseous joint
- posterior sacroiliac joint
- joints between teeth and the bone of mandible
what are primary cartilaginous joints
where the bones are united by hyaline cartilage
where are primary cartilaginous joints found
1st sternocostal joint, xiphisternal joint, epiphyseal growth plates
what are secondary cartilaginous joints
articulating bone is covered with hyaline cartilage with a pad of fibrocartilage between them
where are secondary cartilaginous joints found
symphysis pubis, intervertebral disc, manubriosternal joint
what are synovial joints
joint cavity containing synovial fluid
why do bones crack
the bones are pulled away from each other, expanding the synovial cavity. but the synovial volume stay constant so a partial vacuum is produced. the gases dissolved in the synovial fluid are pulled out of solution giving a popping noise
what are the effects of aging on joints
decreased production of synovial fluid
thinning of articular cartilage
shortening of ligaments and reduced flexibility
what is arthritis
inflammation and stiffness of a joint
what are the symptoms of arthritis
pain, swelling and stiffness
what are the signs of arthritis
swelling, deformity, tenderness, reduced range of movement and abnormal gait
what is osteoarthritis
the wearing or articulating surfaces, giving a loss of joint space and the bones begin to grind
what are subchondral bone cysts
fluid filled sacs in the bone beneath the articulating cartilage in osteoarthritis
what are osteophytes
bone spurs due to new bone formation at the margins of arthritic joints in osteoarthritis
what is subchondyl sclerosis
think layer of increased bone density below the articulating cartilage in osteoarthritis
what is rheumatoid arthritis
an autoimmune disease where autoantibodies attack the synovium causing synovial inflammation (pannus)
where does rheumatoid arthritis usually affect
hands, feet, cervical spine and can involve large joints
what are risk factors for rheumatoid arthritis
- more common in women
- aged between 40-50
what is seen on an x ray in rheumatoid arthritis
- narrowing of joint space
- periarticular osteopenia
- bone erosion in non cartilage protected bone
- deformity
what is periarticular osteopenia
loss of bone substance
what factors affect the stability and range of motion at synovial joints
- shape of articulating bones
- strength and tension of ligaments
- arrangement of muscles
- hormones
- use/disuse
what is a ball and socket joint
where a ball like surface of one bone fits into a cup like surface of another
give examples of a ball and socket joint
hip, shoulder, incudostapedial joint (middle ear)
what movements can occur at a ball and socket joint
flexion, extension, abduction, adduction, and rotation
true or false: the ball and socket joint is biaxial
false - its multiaxial
what is a saddle joint
articulating surface where one bone is saddle shaped (concavoconvex) and the other resembles the legs of the rider. It is a biaxial joint
what movements occur at a saddle joint
flexion, extension, adduction, abduction
give an example of a saddle joint
1st carpometacarpal joint (base of the thumb)
what is a condyloid joint
a biaxial joint where an oval shaped condyl of one bone rests on elliptical cavity of another
what movements occur at a condyloid joint
flexion, extension, abduction and adduction
give examples of condyloid joints
metacarpophalangeal, radiocarpal (wrist) and atlanto-occipital joint
what is a pivot joint
a uniaxial joint where a rounded surface of one bone articulates within a ring formed by the concavity of another bone an fibrous ligament
give examples of pivot joints
proximal radioulnar joint and atlantoaxial joint
what is a hinge joint
a uniaxial joint which is pulley shaped - the convex surface of one bone fits into to concave surface of another
give examples of hinge joints
knee, ankle, humeroulnar joint of the elbow
what are planar joints
where the articulating surfaces are flat or slightly curved to give sliding movements in any axis
give examples of planar joints
sternoclavicular, acromioclavicular, intercarpal and vertebral facet joints
what are the 6 types of synovial joints
- planar
- hinge
- pivot
- ball and socket
- saddle
- condyloid
what is Hilton’s Law
the nerves supplying the joint capsule also supply the muscles moving the joint and the skin overlying the insertions of these muscles
what plexus supplies blood to the synovial joints
periarticular arterial plexus
true or false: articular cartilage is avascular
true
does the synovial membrane have a good blood supply
yes - this is important for maintaining the flow of nutrients to the articulating cartilage through the synovial fluid
what are intra-articular menisci
fibrocartilage in a synovial joint which is not covered by synovium
describe the synovial fluid
- clear/ pale yellow, viscous, slightly alkaline liquid
- made up of hyaluronic acid, lubricin, proteinase and collagenase
what are the functions of synovial fluid
reduces friction, shock absorber, nutrient and waste transporter
what are bursa
sac lined by synovial membrane and filled with synovial fluid to act as a cushion. it reduces friction and allows for free movement
what are tendon sheaths
elongated bursa wrapped around a tendon to reduce friction
describe the synovial membrane
- highly vascularised
- lines the capsule covering exposedbone
- doesn’t cover articular cartilgar
- produces synovial fluid
describe the fibrous capsule
- made up of longitudinal and interlacing bundles of collagen
- completely encloses the joint
- stabilises the joint, resisting dislocation but permitting movement
describe the articular cartilage at synovial joints
- usually hyaline cartilage
- can be fibrocartilage at the acromioclavicular and sternoclavicular joints
- resists compression
- shock absorber
- allows for low friction movement
