midterm Flashcards
last bone to ossify
clavicle
which germ layer is bone formed?
mesodermal tissue
Long bones begin as _____ cartilage in the fetus
hyaline
primary center of ossification
diaphysis
secondary center of ossification
epiphysis
increases diameter of bone and involved in late bones
intramembranous ossification
bones ossified in membrane
parietal bonetemporal boneupper occipital squamosa frontal bone
endochondral ossification primarysecondary
primary- cartilaginous from mesenchymal cells transforms to bone (lengthens bone)secondary-occurs in the epiphyses and apophyses (growth plates)
apophysis
secondary growth centsresults in protuberance/attachment sites
enthesis
highly vascularized site of attachment of tendons and ligamentshigh metabolic activity
growth plates in infant
little blood supply through growth plate
growth plates in chile
no blood supply crossing growth plates
growth plates in adult
no growth plates
where bone is lengthened in growth plates
zone of proliferation
where do Salter-Harris fractures occur?
zone of hypertrophy (open growth plates)
Bone ___% mineral
70
Bone ___% organic
30
80% of bone mass is
compact bone
bone marrow converts to fat ____ to ____
distal, proximal
red marrow is hematopoietically ____
active (yellow marrow is inactive)
yellow bone marrow has more _____ than red
fat
calcium:phosphorus
2:1
calcium deposition is controlled by
mechanical stressVitamin Dparathormonetrace mineralsalkaline phosphatase
functions of parathormone
- stimulate and control rate of bone remodeling2. influence mechanisms governing control of plasma level of calcium
direct effects of parathormone on bone
promotes osteoclastic resorption
direct effect of parathormone on kidney
stimulates Calcium absorption from glomerular fluid
indirect effect of parathormone on intestines
influences rate of Calcium absorption
low serum calcium causes
release of parathormone, take calcium from bone for cellular metabolism
increases in serum calcium stimulate the release of ______ and inactivates bone resorption and osteoclasts
calcitonin
regulates intestinal absorption of mineral and maintain skeletal growth and mineralization
Vitamin D
C.A.T.B.I.T.E.S.
C - CongenitalA - ArthritisT - TraumaB - Blood (hematological)I - InfectionT - TumorE - Endocrine,nutritional,metabS - Soft Tissue
GEOGRAPHIC LYTIC LESION
Destructive lesionSharp bordersLess aggressiveSlow growing, benignNarrow zone of transition
MOTH-EATEN LYTIC LESION
DestructiveRagged bordersMore rapid growthMay be malignant2-5mm diameter
PERMEATIVE LYTIC LESION
Ill-defined“worm-holes”Wide zone of transitionImplies aggressive malignancy
OSTEOBLASTIC LESION
Aka osteogenicRefers to a lesion that produces new bone where it should not
Wide zone of transition
difficult to ascertain where the lesion starts and stops
Narrow zone of transition
sharp margins
SHARP OR “SHORT ZONE OF TRANSITION”
benign
POORLY DEFINED OR “LONG ZONE OF TRANSITION
infection or malignant
Cortex destroyed (eroded or penetrated)
Infection or Malignant tumour
Cortex intact
usually a good sign
Cortex expanded
benign or malignant
Periosteal Response/Reaction
Is the new bone formation stimulated by inflammation, break, tear or stretching of the periosteum
lamellated or “onion-skin”
lesion grows fast and unevenly layers of ossified, concentric shells (periosteum has enough time to lay bone down)
sunburst” or “hair-on-end”
will not have enough time to lay down even a thin shell of bone. tiny fibers that connect the periosteum to the bone (Sharpey’s fibers) become stretched out perpendicular to the bone
lest to most aggressive
solidlaminatedsunburstcodman’s
