Changes in Bone Density

cortex

just a mass 

• -Not all tumors are neoplasms, but all neoplasms are tumors
• -e.g. an intramuscular hematoma is a tumor (lump/mass) but not a neoplasm
• - e.g. even soft tissue swelling following trauma could be considered a tumor!

lesions which result in bone destruction to some extent and produce a defect or hole in the bone. 

-creates a lucency

-tumor may destroy bone or stimulate osteoclasts to resorb bone

lesions that present as radiographic areas of increased bone density or radioopacity

-tumor that stimulates bone production by osteoblasts or produces bone by itself or the tumor undergoes a degree of calcification

Focal areas of bone destruction

-May be well-defined sclerotic margins, well-defined non-sclerotic margins, or indistinct margins

-tend to be benign, indolent lesions

Multiple holes in either cortical (hard) or medullary bone

Each hole may be relatively well defined or not

-tend to be more aggressive

Tumor infiltrates hard and/or spongy bone

difficult to identify extent of bone lysis

the more poorly defined the lesion is, the more permeative it is 

e.g. ewings sarcoma

matrix produced by osteoblasts, if present it tells you that the tumor is making bone; looks like cotton ball dipped in barium! 

described as:

-solid, dense

• -amorphous
• (cloud-like)

-ivory-like

calcification produced by chondroblasts; has discrete structure and features, if present it tells you that the tumor is making cartilage. looks like calcified popped popcorn!

described as:

-stippled

-flocculent

-rings and arcs

• calcification produced by fibroblasts; has discrete structure and features, if present it tells you that the tumor is making cartilage; looks like frosted beer stein (smudgy or hazy) 
• -doesn't have the structure of the chondroid matrix or the density of the osteoid matrix

Layer of dense connective tissue that surrounds the exterior of bones

• -not visible on a radiograph unless stimulated
• -will then produce new bone through the actions of osteoblasts

• -When the periosteum is stimulated to produce new bone through the action of osteoblasts (not an inflammatory response- do not call it periostitis)
• -The new bone is added to the surface of the bone- the underlying cortex may or may not remain intact

• -smooth, solid, uninterrupted--> slow growing, benign, indolent
• -lamellated, interrupted, spiculated, Codman's triangles--> fast-growing, malignant, agressive

A layer of compact (hard) bone that completely envelopes a less dense medullary cavity that contains cancellous bone arranged as trabeculae

• One of two types of osseous tissue that form bones 
• -also known as spongy or trabecular bone
• -less dense and more flexible than cortical bone
• -found at the ends of long bones, proximal to joints and within the interior of vertebrae

-red bone marrow is found here

(aka ischemic necrosis, aseptic necrosis, osteonecrosis)

• Pathophysiology: cellular death and collapse of bone due to lack of blood supply
• -caused by sickle cell anemia, trauma, anything that blocks blood vessels

• Density changes: Focal increase in density
• -Devascularized bone becomes denser 
• -medullary bone infarcts appear as dense amorphous deposits of bone within the medullary cavities

• - subperiosteal bone resorption on radial side of middle phalanges of index and middle fingers 
• -erosion os distal clavicles
• -well-circumscribed lytic lesions in the long bones called brown tumors

mechanical forces

Osteoblasts

Scaphoid bone (waist fracture), femoral head, humeral head.

avascular necrosis

• osteopenia or low bone mass and history of fragility fracture of the hip or spine;
• T score of -2.5 or less in the spine, femoral neck, total hip, or 33% radius;
• T-score between -1 or -2.5 in spine, femoral neck, total hip, or 33% radius, if the FRAX 10-y probability for major fracture is >20% or 10-y probability of hip fracture is >3%

• T-score -2.5 or below in lumbar spine, femoral neck, total, and/or 33% radius;
• low-trauma spine or hip fracture;
• osteopenia or T-score between -1 and -2.5 with fragility fracture of proximal humerus, pelvis, or distal forearm;
• low bone mass or osteopenia and high FRAX fracture possibility

duodenum, jejunum (depends on vitamin D) (15% passive diffusion in jejunum and ileum)

calcium carbonate

calcium citrate

• Alendronate (Fosamax, generic) oral
• Ibandronate (Boniva) oral, IV
• Risedronate (Actonel) oral
• Zoledronic acid (Reclast) IV

drug class that inhibits osteoclast function & bone resorption; strong affinity for hydroxyapatite crystals on bone surface; Decreases osteoclast maturation, number, recruitment, and life span (increased apoptosis)

deposited as hard, brittle crystals in flexible collagen and gives bone its rigidity and strength

a minimally invasive procedure for managing acute painful cerebral fractures; this involves injecting bone cement into the fractured vertebra under fluoroscopic guidance

a minimally invasive procedure that can reduce back pain and restore vertebral body height and spinal alignment; involved reducing the vertebral compression and injecting the cement into this space created within the vertebral body using fluoro guidance

can be measured as fat and fat-free mass in specific measurements by performing a DXA whole body scan

• Midshaft (diaphysis)
• --vs metaphysis or epiphysis