Pathology Ch. 22

Front 1

Osteoid

Back 1

•A specialized protein produced by osteoblasts

Front 2

Osteoblasts

Back 2

•Is transformed into bone by deposition of calcium, phosphate, and other minerals

Front 3

Osteocytes

Back 3

•Osteoblasts that become trapped in tiny pores (Lacunae)

Front 4

The Musculoskeletal System

Major Determinants of Disease (1)

Back 4

•Bone health requires constant mechanical stress

•Bones are metabolically active

•Bones are dramatically affected by hormones and vitamins

Front 5

The Musculoskeletal System

Major Determinants of Disease (1)

Back 5

•Bones are affected by bone marrow

(Hematopoietic) disorders.

•Fractures are a major health problem for the elderly

•Bones are a favorite site for metastatic cancer

Front 6

Skeletal Deformities and Disorders of Bone Growth

Scoliosis

Back 6

•Abnormal lateral curvature of upper spine

Front 7

Skeletal Deformities and Disorders of Bone Growth

Kyphosis

Back 7

•Abnormal forward curvature

Front 8

Skeletal Deformities and Disorders of Bone Growth

Lordosis

Back 8

•Abnormal backward curvature (may protrude belly)

Front 9

Disorders of Bone Growth

Achondroplasia

Back 9

•Genetic Syndrome

•Short - limbed dwarfism, paternal age?

Front 10

Disorders of Bone Growth

Osteogenesis Imperfecta

Back 10

•Genetic Syndrome

•Cartilage Defects

•Brittle bone disease, heart valves, inner ear affected (Deafness), bluish sclera

Front 11

Disorders of Bone Growth

Paget Disease

Back 11

•Common

•Cause may be chronic viral Infection.

•Rapid bone formation and breakdown, osteoblastic exhaustion later; pain deformity, fracture...

1% - osteosarcoma

Front 12

Fracture Types

Back 12

•Closed

•Open

•Comminuted -Multiple Fractures

•Greenstick -Partial Fracture

Front 13

Fracture Types

Back 13

•Impacted -Sudden end to end force causes bone to collapse on itself

•Compression -Sudden end to end force causes bone to collapse on itself (Vertebrae)

•Spiral

•Pathologic

Front 14

Fractures (Healing)

Back 14

1. Immediately after fracture a pool of blood (hematoma) forms.

2. Within a week or two, granulation tissue, fibrous (scar) tissue, and woven bone appear and form a loose union of the broken ends.

Front 15

Fractures (Healing)

Back 15

3. In 2 to 4 weeks granulation tissue, woven bone is resorbed and replaced by a bony callus formed of a mixture of spongy cancellous bone and cartilage that is capable of limited weight-bearing.

4. Final Stage: Excess, unstressed callus disappears as stressed callus matures into dense, cancellous bone

Front 16

Bone Infection / Bone Infarction

Osteomyelitis

Back 16

•In adults, bacterial Infection from direct traumatic implantation into bone

-In boys, Staph Infection elsewhere

Front 17

Bone Infection / Bone Infarction

Aseptic (Avascular) Necrosis

Back 17

•Impaired blood flow, corticosteroid (mech. Unclear)

-Infarction, Necrosis

-Especially head of femur, carpals

-Mainly issue in growing children (growth = Increase blood flow demands), and elderly (atherosclerosis)

Front 18

Osteomalacia: Soft Bone

Back 18

•The importance of steroid (Bone Protein) - does not mineralize properly

Front 19

Osteomalacia: Soft Bone

Back 19

•Soft, qualitative problems of bone hardness

-Pathogenesis: Inadequate Calcium, Vit. D, Phosphate, Rickets: Vit. D, malformations in growing kids

-Renal osteodystrophy: Kidneys do not excrete PO4 - properly, blood levels rise, drives Ca++ down in blood causes PTH increases & Osteoclasts stimulated.

Front 20

Bone Tumors

Back 20

•Metastatic Carcinoma(Most Common) breast, prostate, and lung cancer are common sites of origin

•Most common malignant tumor of bone is osteosarcoma

•80% primarily bone tumors = knee

Front 21

Bone Tumors

Bone-Forming Tumors

Back 21

•Benign: Small, little consequence

•Malignant (Osteosarcoma): 75% during growth (epiphysis of long bones, cell division)... Tibia or femur near knee

Front 22

Bone Tumors

Cartilage-Forming Tumors

Back 22

•Benign: Little Consequence

•Malignant (Chondrosarcoma): neoplastic cartilage; most are low grade, sluggish tumors, 5-yr. Survival 80%

Front 23

Bone Tumors

Fibrous Tumors and Tumor-Like Conditions

Back 23

•Fibrous cortical defect, not neoplasm

•Fibrous dysplasia: Children. Benign.

•Fibrosarcoma: Malignant tumor of fibrocytes (Seen in various tissues)

Front 24

Bone Tumors

Back 24

•Other Tumors of bone: Multiple Myeloma: B-lymphocytes (Plasma cells of haemopoetic system) common in sternum, vertebra, ribs, cranium.