MSK - Bones Flashcards
Name the classification of bones by shape?
Describe the features of each
Flat bone - (frontal) Curved to protect organs
Short Bone - (carpal)
Equal in length and wide
Long Bone - (femur)
Longer than they are wide. Muscles act on them as rigid leavers
Irregular bone - (vertebra)
Irregular in size and shape
Sesamoid bone - (patella) embedded within tendon or muscle
Sutural bone - within a cranial suture
What cartilage is on the head of a long bone?
Articular cartilage
When is the medullary cavity red and yellow?
Red - actively forming blood cells
Yellow - red marrow is replaced by fat
What type of bone do short bones consist of?
Do they have a epiphysis or diaphysis?
What is located between the trabeculae?
Mainly spongy bone
No epiphysis and diaphysis
Bone marrow
Where does the nutrient artery enter the diaphysis?
Nutrient foramen
What area does the periosteal artery supply?
Periosteum and outer 1/3rd of cortex
Where do the metaphyseal arteries enter metaphysis?
Site of attachment of capsule
What is avascular necrosis?
What are the causes?
What happens?
Death of bone due to interruption of blood supply
Fracture, dislocation, steroid use, radiation, decompression sickness
Leads to collapse of necrotic segment and secondary osteoarthritis
What happens if you break the neck of the femur in terms of blood supply?
Blood supply can be interrupted from lateral an medial femoral circumflex blood supply
Obturator artery cannot supply enough blood alone, bone dies which leads o arthritis
What is a joint?
Name 3 structural classifications
Name 3 functional classifications
Articulation between two or more bones
Fibrous, cartilaginous, synovial
Synarthrosis - immovable
Amphiarthrosis - slightly movable
Diarthrosis - freely movable
Describe the movement in synarthrosis, amphiarthrosis and diarthrosis
Synarthrosis - immovable
Amphiarthrosis - slightly movable
Diarthrosis - freely movable
What type of joint is a suture joint?
Where does it occur?
How much movement does it have?
Fibrous joint
Only occurs in cranium
Synarthrosis
What type of joint is a syndesmosis?
How much movement does it have?
Where do they occur?
Fibrous joint
Amphiarthrosis - small amount of movement
Posterior sacroiliac joint
What type of joint is a gomphosis?
Where are they found?
Fibrous joint
Tooth - sits in tooth so key and fibrous tissue that unites it with bone
How are primary cartilaginous joints united?
How are they functionally classified?
Give an example
Hyaline cartilage
Synarthrosis - immovable joint
1st sternocostal joint, epiphyseal growth plates
Describe a secondary cartilaginous joint
How much movement is there?
Give an example
Articulating bones covered with hyaline cartilage with a pad of fibrocartilage between them
Amphiarthrosis
Symphysis pubic, intervertebral disc
What is a synovial joint?
How much movement do they have?
Joint cavity contains synovial fluid
Diarthrosis - freely movable
What are the three exceptions of hyaline cartilage in synovial joints?
Acromioclavicular
Sternoclavicular
Temporomandibular
Atypical synovial joints
Contain fibrocartilage
Describe synovial fluid
What is it composed of?
What are its functions?
How much is in a large joint?
Clear or pale yellow fluid.
Composition: Hyaluronic acid, lubricants, proteinase, collagenase
Functions: Reduces friction, shock absorption, nutrient and waste transportation.
Fluid volume
What are the characteristics of a synovial joint and describe.
Articular cartilage - hyaline (3 exceptions), low frictions movement, resists compression
Fibrous capsule - collagen, completely encloses joint except when interrupted by synovial protrusions, stabilises joint.
Synovial membrane - thin, highly vascularised membrane. Produces synovial fluid. Lines capsule, covers exposed osseous surfaces, tendon sheaths, bursae. Does NOT cover Articular cartilage.
Synovial fluid - clear or pale yellow fluid. Reduces friction, shock absorption, nutrient and waste transportation.
Intra-Articular discs - fibrocartilage (not covered by synovium)
Fat pads
What are bursae and tendon sheaths?
Specialised areas of synovial membrane
Bursa - sac lined with synovial membrane, filled with synovial fluid, communicating or non-communicating with joint cavity
Tendon sheaths - elongated bursa, wrapped around a tendon
What is the blood supply to synovial joints?
What is the blood supply to Articular cartilage?
Describe the blood supply to fibrous capsule and ligaments
And synovial membrane?
Periarticular arterial plexus
Articular cartilage is avascular - completely dependent on diffusion to get nutrients
Fibrous capsule and ligaments have poor blood supply
Synovial membrane has rich blood supply
What is Hilton’s Law?
The nerves supplying the joint capsule also supply the muscles moving the joint and skin overlying the insertions of these muscles
What are the six types of synovial joints?
What is classification based upon?
Planar Hinge Pivot Condyloid Saddle Ball and socket
Shape of Articular surface
Describe the planar joint
Name some examples
Flat or slightly curved articulating surface
Gliding or sliding movements
Non axial
Sternoclavicular, acromioclavicular joint, intercarpal joints
What is the hinge joint?
Name three examples
Uniaxial
Pulley-shaped - convex surface of one bone fits into concave surface of the other
Knee, ankle, humeroulnar joint of elbow
Describe a pivot joint?
Give an example
Uniaxial
Rounded or pointed surface of one bone articulates within ring formed by the concavity of another bone and fibrous ligament
Proximal radioulnar joint - used for pronation and supination
What is a condyloid joint?
What movements does it allow?
Give an example
Biaxial joint - oval shaped condyle of one bone rests on elliptical cavity of another
Flexion, extension, abduction and adduction
Wrist (radiocarpal), Metacarpophalangeal joints
Describe a saddle joint
What movements does it allow?
Give an example
Biaxial joint
One bone is saddle shaped (concavoconvex), the other bone resembles the legs of the rider
Flexion, extension, abduction and adduction
1st carpometacarpal joint
Describe a ball and socket
Describe movements
Name two examples
Multiaxial
Ball-life surface of one bone fits into cup like surface of another
Movements: flexion, extension, abduction, adduction and rotation
Hip, shoulder
What is difference between symphyses and syndesmoses?
Symphyses - connected by fibrocartilage
Syndesmoses - connective tissue
What are the functions of the skeleton? (5)
Support - framework for posture
Protection - skull protects brain
Movement - attachment site for muscles and tendons, joints allow range of motion
Mineral and growth factor storage - resevoir for Ca2+ and phosphate, release minerals into the blood, IGF
Haematopoeisis - marrow within cavities of bones
What are the factors that affect stability and range of motion at a synovial joint?
Structure/shape of articulating bone Strength and tension of joint ligaments Arrangement and tone of muscles Apposition of neighbouring soft tissues Hormones e.g. Relaxin in pregnancy - softens collagen bundles Use/disuse
What happens when people ‘crack joints?’
Bones are pulled away from each other Synovial cavity expands Synovial fluid volume stays constant Partial vacuum produced Gasses dissolved in synovial fluid are pulled out of solution Makes popping sound
What is the effect of ageing on joints?
Decreased production of synovial fluid
Thinning of articular cartilage
Shortening of ligaments and decreased flexibility
Degenerative changes
What is arthritis?
What are the symptoms?
What are the signs?
What is the most common type?
Inflammation and stiffness of a joint
Symptoms: pain, swelling, stiffness
Signs: redness, swelling, deformity, tenderness, reduced range of movement, abnormal gait
Osteoarthritis
What is rheumatoid arthritis?
What happens?
What damage to other organs can it cause?
What is the peak age?
What gender is it more common in?
Autoimmune disorder - autoantibodies attack the synovium causing synovial inflammation
Joint erosion and deformity MCPJ and PIPJ (first joint in fingers)
Can cause damage to other organs - eyes, skin, lungs, heart and blood vessels, kidneys, blood (anaemia)
40-50 years
Women
What are the Xray features of rheumatoid arthritis?
Narrowing of joint space
Periarticular osteopenia
Juxta-Articular bony erosions (non cartilage protected bone)
Subluxation and gross deformity (bones not in correct environment, starting to ulnar deviate - if in hand)
What factors restrict movement around a joint?
Ligaments, muscle tendons, interference from other structures, depth of bony articulation (less stable, more mobile)
