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Flashcards in MSK Deck (92)
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1
Q

What is a bone fracture?

A

Breach in continuity of bone

2
Q

When do fractures occur?

A

Non-physiological loads applied to normal bone;
Physiological loads applied to abnormal bone

3
Q

What are the types of joints?

A

Fibrous, cartilagenous, synovial joints

4
Q

What is rheumatology?

A

Medical management of joint and MSK problems

5
Q

What is rheumatism?

A

A colloquial term for bone/joint/muscle pain

6
Q

What are synarthroses?

A

Immovable joints, mostly fibrous (eg. skull sutures)

7
Q

What are amphiarthroses?

A

Slightly moveable joints, most cartilaginous (eg. intervertebral discs)

8
Q

What are diarthroses?

A

Freely moveable joints, mostly synovial (eg. hip)

9
Q

What are suture joints?

A

Fibrous joints.

Occur only between bones of the skull (allow skull growth in development)

Adjacent bones interdigitate

Junction filled with very short tissue fibres

10
Q

What are syndesmoses?

A

Fibrous joints.

Bones are connected by a cord (ligament) or sheet (interosseous membrane) of fibrous tissue.

Amount of movement permitted is proportional to length of fibre

11
Q

What is a gomphoses?

A

Fibrous joint.

A peg-in-socket fibrous joint found only in tooth articulation

12
Q

What are synchondroses?

A

The bones are directly connected by hyaline cartilage. These are usually amphiarthroses ie. slightly moveable eg. costal cartilage of the ribs

13
Q

What are symphyses?

A

Here the connecting cartilage is a pad or plate of fibrocartilage

14
Q

What are the classifications of joint?

A
15
Q

What are the 5 components of synovial joints?

A
  1. Articular cartilage
  2. Joint capsule -the inner layer is the synovial membrane,
  3. Joint (synovial) cavity - a space filled with synovial fluid.
  4. Synovial fluid
  5. Reinforcing ligaments
16
Q

What are the key components of articular (hyaline) cartilage?

A

Almost frictionless surface

Resists compressive loads

High water content

Low cell content

No blood supply

17
Q

What are the components of cartilage?

A

Water, proteoglycans, collagen

18
Q

Where is synovial fluid?

A

Covers articulating surfaces with thin film (e.g. healthy knee just 0.5 ml fluid)

19
Q

How is synovial fluid modified from plasma?

A

Modified from plasma by synovial membrane (synoviocytes)

20
Q

What is synovial fluid?

A

Fluid, proteins, charged sugars that bind water eg. hyaluronate

Result: slimy fluid (like egg white)

21
Q

What is the function of synovial fluid?

A

Reduces friction during articulation

22
Q

Where is the synovial membrane?

A

Sits on the joint capsule and encloses synovial cavity

23
Q

What is the function of the synovial membrane?

A

Secretes synovial fluid components eg. hyaluronate

24
Q

What do ligaments do?

A

Connect bone to bone

25
Q

How are ligaments different to tendons?

A
  • Similar to a tendon but with less regularly arranged fibres
  • Can stretch up to 6% before breaking and may contain more elastic fibres than tendon (generalisation)
26
Q

What is the function of tendons?

A

Stabilise joints

Allow muscles to be accommodated at a distance from their insertion, e.g. muscles of the forearm move the fingers. Provides a solid base (insertion to bone) on which muscles can pull

27
Q

Where do most tendon ruptures occur?

A

The musculotendinous junction

28
Q

What is a first class lever in the musculoskeletal system?

A

In a first class lever, the fulcrum is in the middle (the elbow joint) the force is at one end (the triceps muscle) and the resistance is at the other end (the weight being pulled).

29
Q

What is a second class lever in the musculoskeletal system?

A

In a second class lever, the fulcrum is at one end (eg. Temperomandibular joint) the force is at the other end (the muscles of the chin) and the resistance is in the centre (the muscles attached to the coronoid process).

30
Q

What is a third class lever in the musculoskeletal system?

A

In a third class lever, the fulcrum is at one end (eg. elbow joint), the force is in the middle (the biceps muscle) and the resistance is at the other end (the weight being pulled).

31
Q

How is a ball and socket joint held in place?

A

Held securely in place by strong ligaments and heavy cylindrical joint capsule

32
Q

What are the main stabilising ligaments at the hip joint?

A

Iliofemoral

Pubofemoral

Ischiofemoral

33
Q

What are the tendons stabilising the shoulder?

A

Long head of Biceps brachii

Tendons of the rotator cuff: subscapularis, supraspinatus, infraspinatus and teres minor

34
Q

What are joints?

A

Spaces between bones bridged by fibrous and/or cartilaginous tissue

35
Q

What makes a bone a long bone?

A

It is in the appendicular skeleton.

It is cancellous and compact bone.

It has articular hyaline cartilage.

36
Q

What type of bone is flat bone? Give some examples.

A

Thin inner and outer layer of compact bone.

eg. skull, ribs, sternum, scapula

37
Q

What is an irregular bone? Give some examples

A

One that doesn’t fit any of the other categories. Examples include vertebrae and sphenoid bones

38
Q

What are short bones? Give some bones

A

Cuboidal/round in shape.

Cancellous bone surrounded by compact bone.

Wrist and midfoot.

39
Q

What is a sesamoid bone? Give some examples.

A

Small bones in tendons.

Patella and sesamoid.

They reduce friction on the tendon

40
Q

What is bone made of?

A

20% organic component (osteoid - 90% type 1 collagen, 10% GAGs)

70% inorganic component (mineral - hydroxyapatite)

10% water

41
Q

What is the function of the organic component of bone?

A

It provides elasticity

42
Q

What is the function of the inorganic component of bone?

A

Facilitate water exchange and provides stiffness

43
Q

What is woven bone?

A

Coarse collagen fibres with low mineral content

44
Q

How quickly is woven bone produced?

A

It is produced very rapidly (fractures, embyronic development)

It gets remodelled

45
Q

What is lamellar bone made of?

A

Regular parallel collagen fibres

46
Q

What are the two types of lamellar bone?

A

Cortical and cancellous bone

47
Q

What is cortical bone?

A

It is the outer shell of long bones, Haversians canals, osteocytes in lacunae. The lamellar and canals form an osteon. Volkmann’s canals communicate with the periosteum.

48
Q

What is cancellous bone?

A

Lamellae forming trabeculae, oriented along lines of stress. Affected in osteoporosis.

49
Q

What is a simple fracture?

A

A clean break in bone that causes no or very little damage to the overlying skin

50
Q

What is compound ‘open’ fracture?

A

A broken bone piercing and oftenprotruding through the overlying skin

51
Q

What is greenstick fracture?

A

An incomplete fracture in which the bone is bent. This happens most commonly in children.

52
Q

What is a communited fracture?

A

A multifragmentary fracture, more than 2 pieces

53
Q

What is a complicated fracture?

A

A broken bone that has also damaged surrounding structures or organs

54
Q

What happens during the inflammatory phase of fracture healing?

A

Decreased blood flow. Periosteal stripping. Osteocyte death.

Haemotoma develops within the first few hours. Inflammatory and fibroblasts infiltrate the bone in the next few days

55
Q

What is the reparative phase of fracture healing?

A

Approx 2 weeks after the fracture took place. Callus eventually hardens over a 6-12 week period.

Fibroblasts produce fibrous tissue, chondroblasts produce cartilage, osteoblasts produce osteoid. HIgh vascularity. Progressive matrix mineralisation.

56
Q

What happens during the remodelling phase during fracture healing?

A

Woven bone remodelled into stronger lamellar bone. This can take months to years.

57
Q

What are principles of fracture management?

A

Reduce

Immobilisation

Rehabilitate

58
Q

How is vitamin D produced from the skin?

A

UVB rays from the sun turns cholesterol in the skin into vitamin D

59
Q

What is the main function of Vitamin D?

A

It helps calcium and phosphorus get absorbed from our diet in the gut

60
Q

What is the active form of vitamin D?

A

Calcitriol.

1,25 dihydroxyvitamin D

61
Q

How does parathyroid hormone increase calcium levels?

A

Increases reabsorption from the distal convoluted tubules in the kidneys.

Increased active absorption in the duodenum and jejunum (with help from Vit D)

Increased resorption from bones via osteoclasts

62
Q

What hormones influence osteoblasts?

A

BMP, TGF-B and FGF

63
Q

How do osteoclasts resorb bone?

A

Release H+ and MMPs

64
Q

What influences osteoclast activity?

A

RANKL, OPG and PTH

65
Q

What is OPG secreted by?

A

Secreted by osteoblasts

66
Q

How does OPG work?

A

Binds to RANK ligand, therefore neutralising it.

Reduced activation of osteoclasts and differentiation from haematopoietic stem cells.

Reduced resorption of bone

67
Q

Where is RANKL secreted?

A

Osteoblasts

68
Q

How does RANKL work?

A

Binds to RANK receptor on haematopoietic precurosr and osteoclasts.

Stimulates activation of osteoclasts from precursor.

Increases resorption of bone.

69
Q

What is Wolff’s law?

A

Bone is deposited in line with where load is being placed and therefore resorbed where less load is being placed

70
Q

What is fibrous joint? Give some types.

A

Fibrous tissue, little movement possible.

Sutures, syndemoses, gomphoses

71
Q

What are primary cartilagenous joints? Give some examples

A

Hyaline cartilage, no movement possible.

Costosternal joints

72
Q

What are secondary cartilagenous joints? Give some examples

A

Articulating surface of hyaline cartilage with fibrocartilage.

Manubriosternal joint, symphysis pubis, intervertebral discs

73
Q

What are synovial joints?

A

Hyaline cartilage lines articulating surfaces

Synovial fluid lubricates joint cavity

Synovial membrane covers cavity

Fibrous joint capsule reinforced by ligaments

74
Q

What are ligaments and what is their function?

A

Flexible bands connecting bones or cartilage together.

Strengthen and stabilise joints

75
Q

What are tendons and what is their function?

A

Connect muscle and bone together.

Allow for transmission of force of contraction during movement

76
Q

Where is procollagen produced?

A

It is produced inside the cell and then secreted

77
Q

What is the function of bones?

A

Raises us from the ground against gravity

Dictates body shape

Transmits body weight

Forms joint system for movement

Protects vital structure

Contains bone marrow

Stores minerals

78
Q

What is the axial skeleton?

A

Bones of the head and trunk

79
Q

What is the appendicular skeleton?

A

Supports the appendages (everything but the head and the trunk)

80
Q

What does fibroblast growth factor 23 (FGF-23) do?

A

Decreases renal reabsorption of phosphate. If phosphate level is too high, FGF-23 levels increase. If phosphate level is too low, FGF-23 levels increase.

81
Q

Fracture definition:

A

A soft tissue injury, complicated by a breach of bone continuity

82
Q

What is hyaline cartilage made of?

A

Water, proteoglycans and collagen.

High water and proteoglycans content

Low cell content

No blood supply

83
Q

What is an entheses?

A

Where a tendon inserts into a bone.

84
Q

What are the two types of entheses? What is the difference?

A

Fibrous: tendon inserts directly into bone

Fibrocartilagenous: entheses has four transitional zones

85
Q

Where do osteoblasts come from?

A

Mesenchymal cells -> osteoprogenitor cells -> osteoblasts

86
Q

What does osteiod contain?

A

Type 1 collagen, GAGs and proteoglycans

87
Q

Do osteoblasts create the osteoid or the matrix first?

A

Osteoid (provides elasticity) then matrix vesicles rich in minerals (mineralises the extracellular matrix by depositing hydroxyapatite within collagen fibrils)

88
Q

Where do osteoclasts come from?

A

Bone marrow -> monocytes -> specialised macrophage (osteoclasts)

89
Q

How do osteoclasts work?

A

Secrete acids, which break up the hydroxyapatite, releasing calcium and phosphate

90
Q

What is coupling?

A

Bone formation occurs at sites of previous bone resorption

91
Q

Why do we need to remodel bone?

A

Repair damage, obtain minerals, form bone shape, reorganise fibrils

92
Q

How does RANKL work?

A

Binds to RANK on the surface of pre-fusion osteoclasts that stem from myeloid precursors, converting them into multinucleated then finally activated osteoclasts