MSK Module I Flashcards
Cortical bone (compact bone) makes up how much of the human skeleton?
80%
Does cortical bone (compact bone) have a slow or fast turnover rate?
Slow
What is the makeup of cortical bone (compact bone)?
Dense, tightly packed osteons w/ Haversian canal system
Cancellous bone (trabecular or spongy bone) makes up how much of the skeletal mass?
20%
Does cancellous bone (trabecular or spongy bone) have a high or low turnover rate?
Higher turnover compared to compact
Cancellous bone (trabecular or spongy bone) is less dense than cortical bone, but has what?
Large surface area
Because of cancellous bone (trabecular or spongy bone) having a large surface area, it is more susceptible to what?
Bone density loss
What is Wolff’s Law?
Mechanical stress/gravity stimulate bone remodeling
(mechanical stress increases bone density along “stress lines” or “gravity vectors”)
The density of the femoral neck varies due to what?
Mechanical stress lines
Areas not in the stress lines of the femoral neck may become susceptible to what?
Fracture
What is the periosteum?
Thin, double-layered, tough fibrous membrane that surrounds all bone except at ligament or tendon insertion sites
What is contained in the inner layer (cellular layer) of the periosteum?
-Sharpey’s fibers: anchor periosteum as well as tendons&ligaments to cortical bone
-Active and resting osteoblasts
What is contained in the outer layer (fibrous layer) of the periosteum?
-Capillaries and nerves
What is a periosteal reaction of the outer layer of the periosteum?
Fracture cortex or expanding tumor may disrupt periosteum and generate pain
Where is myeloid tissue located in bone marrow?
In the cavities between osseous component of bone (myelos=marrow)
What is the function of red (active) bone marrow?
Blood cell formation
-All RBCs, platelets, 60-70% of WBCs
What produces the other 20-30% of WBCs?
Lymphatic tissue of spleen, lymph nodes, thymus
Where is red (active) bone marrow located in adults?
Trabecular/Lymphatic tissue of spleen, lymph nodes, thymus bone of pelvic bones, vertebrae, cranium and mandible, sternum and ribs, proximal femur and humerus
What does the “yellow” of yellow (inactive) bone marrow represent?
Presence of fatty acids
Where is yellow (inactive) bone marrow located in adults?
Medullary cavity of long bones
What is a bone scan? What will it show?
Tracer injected/accumulates in areas of high cell metabolism/turnover
Scan will show normal areas of red bone marrow as well as abnormal areas of bone cellular metabolism
(tumor, infection, fracture/bine repair, arthritis, etc.)
What is apheresis?
Collection of stem cells by filtering blood for circulating blood cells (PBSC- peripheral blood stem cells)
What is a bone marrow harvest?
Collection of stem cells directly out of bone
*pelvis and sternum MC sites to harvest bone marrow
Stem cells can be filtered from blood in what structure after a baby is born?
Umbilical cord