Term
Name the 3 sections of a long bone, and where each is located |
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Definition
1. Epiphysis - head of bone 2. Metaphysis - between two other zones where growth occurs 3. Diaphysis - the shaft |
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Term
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Definition
The CT sheath that covers bones |
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Term
(T/F) The periosteum provides blood supply to bones |
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Definition
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Term
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Definition
The lining of the medullary cavity |
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Term
What is contained within the endosteum? |
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Definition
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Term
(T/F) This is the site of hematopoiesis |
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Definition
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Term
Which 4 bones does this process occur in in adults? |
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Definition
1. Sternum 2. Cranium 3. Ribs 4. All long bones |
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Term
What are the two bone types? |
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Definition
1. Spongy (cancellous/trabecular) 2. Compact (cortical) |
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Term
Name 4 components of compact bone structure |
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Definition
1. Haversian system 2. Lamellae (matrix rings) 3. Haversian canals 4. Osteocytes in lacunae |
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Term
What are the two components of a bone's composition, and what contribution does each component contribute? |
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Definition
1. Collagen matrix - the "scaffolding" 2. Hydroxyapatite (Ca10(PO4)6(OH)2) - the "bricks" |
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Term
What determines the composition of a bone? |
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Definition
Balance between osteoblast and osteoclast activity |
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Term
What is the function of osteoblasts? |
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Definition
- Ca2+ deposition - Increases alkaline phosphotase |
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Term
What is the function of osteoclasts? |
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Definition
- Bone resorption (breaking down bone) to release calcium |
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Term
How is osteoclast/osteoblast activity regulated? |
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Definition
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Term
What type of receptors do osteoclast precursors have? |
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Definition
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Term
What two substances do osteoblasts make? |
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Definition
1. RANK ligand 2. Osteoprotegrin (OPG) |
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Term
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Definition
- Stimulates osteoclast activity when it binds with RANK-R on osteoclasts |
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Term
What does OPG do? How does it do this? |
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Definition
- Inhibits osteoclast activity - Joins with RANK-L therefore no binding at RANK-R |
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Term
(T/F) Estrogen presence decreases OPG synthesis |
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Definition
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Term
(T/F) In men, testosterone is converted to estrogen in bone by aromatase |
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Definition
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Term
Which two substances (hormonal or otherwise) increase osteoclast activity? |
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Definition
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Term
(T/F) Vitamin D3 needs to be activated before it induces osteoclast activity |
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Definition
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Term
Which organ activates it, and what is active vitamin d3 (1,25-D3) called? |
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Definition
- Kidney (renal activation) - Calcitriol |
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Term
What does calcitriol cause, other than bone resportion? |
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Definition
Increased GI absorption of Ca2+ and PO4 |
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Term
What does increased Ca2+ and PO4 on the blood trigger? |
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Definition
Bone mineralization by osteoblasts |
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Term
What is the effect of growth hormone on bone remodeling? |
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Definition
GH increases osteoblast activity therefore increased bone formation |
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Term
What is the effect of cortisol on bone remodeling? |
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Definition
Cortisol causes removal of the bone matrix by stimulating osteoclasts |
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Term
What is responsible for cartilage production? |
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Definition
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Term
Describe how bones are lengthened |
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Definition
1. Chondrocytes produce cartilage 2. Osteoblasts invade the newly synthesized cartilage 3. Cartilage phosphate becomes calcified by osteoblasts, making it more rigid |
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Term
Where does bone growth occur? |
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Definition
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Term
(T/F) Androgens stimulate the close of the epiphyseal plate |
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Definition
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Term
What is complete bone trauma? Incomplete? |
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Definition
A complete fracture; a partial fracture |
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Term
Describe what occurs with a greenstick break, and what type of trauma is this? |
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Definition
- Bone splits similar to a young tree (doesn't brake cleanly) - Incomplete |
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Term
Why is a greenstick fracture more likely to occur with children? |
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Definition
Because their bones are still developing, therefore do not have a full mineralization and are more flexible |
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Term
What is an open break? A close break? |
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Definition
Open = bone penetrates skin; closed = break remains within tissue |
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Term
What is a segmented fracture? A comminuted fracture? |
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Definition
Segmented: only two pieces created - 1 fracture line Comminuted: bone has broken into several pieces - multiple fracture lines |
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Term
List the 3 common fracture types, and describe each |
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Definition
1. Transverse - 90 degree angle to the bone 2. Spiral - One part of bone is twisted 3. Oblique - at a diagonal to bone axis |
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Term
List 4 other types of bone fractures? |
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Definition
1. Impacted 2. Pathological 3. Stress 4. Depressed |
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Term
Describe impacted fractures |
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Definition
Fracture caused by bone segments being driven into each other |
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Term
Describe pathological fractures |
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Definition
The bone is made weak by a pathology |
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Term
Describe stress fractures |
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Definition
Fracture is not through the entire bone, but multiple fracture lines that weaken the bone overall |
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Term
Describe depressed fractures, and where they usually occur |
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Definition
Bones are displaced inwards - usually happens in the skull (blunt force trauma) |
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Term
List the two special types of fractures |
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Definition
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Term
What occurs in a Colles' fracture? |
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Definition
Occurs at the distal radius, where the tips of the radius are broken off |
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Term
What occurs in a Pott's fracture? |
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Definition
Occurs at the ank;e, can break the tips of the fibula/tibia off |
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Term
List common symptoms of fractures? |
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Definition
swelling loss of function/deformity crepitus (sound of bone breaking) pain early numbness |
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Term
List the pathophysiological steps to a fracture, and what occurs in each |
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Definition
1. Bleeding/hematoma - under the periosteum 2. Granulation tissue is formed 3. Procallus formation 4. Bony callus created 5. Remodelling |
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Term
What is responsible for forming the procallus? |
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Definition
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Term
What is osteogenesis, and what step does it occur at? |
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Definition
"Throwing bone in wherever you can" - creation of the bony callus |
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Term
What cells are the most important for bone remodeling, how long does the remodeling occur for, and what is the purpose of it? |
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Definition
- Osteoclasts - 3-4 months - Removes parts of the bony callus that are not needed |
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Term
List the 5 factors that affect bone healing |
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Definition
1. Degree of damage 2. Inflammation/blood supply 3. Approximation 4. Foreign material 5. Systemic factors |
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Term
What is approximation? What two things does it consist of? |
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Definition
How well the bones are realigned to their original position. Reduction and immobilization |
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Term
What is the purpose of reduction? |
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Definition
Getting the bones into their original alignment |
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Term
What is the purpose of immobilization? |
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Definition
Preventing motion so that calcium and phosphate is laid down right away |
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Term
What is depridement, and why is it important for bone healing? |
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Definition
- Removal of foreign material from the site of break - Important because foreign materials increase recovery time |
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Term
List 3 systemic factors that affect bone repair |
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Definition
1. Diabetes 2. Glucocorticoids 3. Nutrition |
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Term
List 6 complications that can arise with healing? |
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Definition
Muscle spasm Infection Ischemia Compartment syndrome Fat emboli Non-union |
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Term
How do muscle contractions complicate healing, and how is this combated? |
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Definition
- Change approximation (unalign bone) - Traction - counteracts muscle spasms and ensures proper approximation |
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Term
What is compartment syndrome? |
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Definition
Initial swelling after trauma can squeeze nerves and vessels, leading to reduced healing |
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Term
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Definition
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Term
How is compartment syndrome avoided? |
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Definition
By utilizing multiple casts over the healing process to ensure proper fit |
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