Bone Fractures (Breaks)

Bone Fractures (Breaks) Bone fractures are classified by:

The position of the bone ends after fracture (displaced vs. nondisplaced)

The completeness of the break (complete vs. incomplete)

The orientation of the bone to the long axis (linear vs. transverse)

Whether or not the bones ends penetrate the skin (compound vs. simple)

As well as…

Common Types of Fractures

Table 6.2.1

Common Types of Fractures

Table 6.2.2

Common Types of Fractures

Table 6.2.3

Stages in the Healing of a Bone Fracture1. Hematoma formation

(immediate – 1st day or 2) Torn blood vessels

hemorrhage

A mass of clotted blood (hematoma) forms at the fracture site

Site becomes swollen, painful, and inflamed

Figure 6.13.1

Stages in the Healing of a Bone Fracture2. Fibrocartilaginous callus

forms (few days – week or 2) Granulation tissue (soft callus)

forms a few days after the fracture

Capillaries grow into the tissue and phagocytic cells begin cleaning debris

Figure 6.13.2

Stages in the Healing of a Bone Fracture Fibrocartilaginous callus forms when:

Osteoblasts and fibroblasts migrate to fracture

Fibroblasts secrete collagen fibers to connect bone (some become chondroblasts = cartilage)

Osteoblasts begin forming spongy bone

Osteoblasts furthest from capillaries secrete cartilaginous matrix that later calcifies

Stages in the Healing of a Bone Fracture3. Bony callus formation (few

weeks – 2 to 3 months) More bone trabeculae

appear in fibrocartilaginous callus

Fibrocartilaginous callus converts into a bony (hard) callus = firm union

Figure 6.13.3

Stages in the Healing of a Bone Fracture4. Bone remodeling (up to

several months after bony callus)

Excess material on bone shaft exterior and in medullary canal removed

Compact bone laid down to reconstruct shaft walls

Figure 6.13.4

Homeostatic Imbalances Osteomalacia - inadequately mineralized bones (soft

and weak) in adults

Main symptom = pain when weight is put on affected bone

Insufficient calcium in diet, or vitamin D deficiency Rickets – inadequately mineralized bones of

children

Bowed legs and deformities of the pelvis, skull, and rib cage

Insufficient calcium in the diet, or vitamin D deficiency

Example: Infants of breastfeeding mothers deficient in Vitamin D will also be Vitamin D deficient and develop rickets

Osteoporosis – bone-thinning disease (reabsorption outpaces deposition)

30% of women over age 60-70 (70% by 80); 20% men over 70 Makes bones fragile and fracture-prone (even a sneeze

can cause fracture) Often results in vertebral collapse (broken hips)

Osteoporosis: Treatment Calcium and vitamin D supplements

Increased weight-bearing exercise

Hormone (estrogen) replacement therapy (HRT) slows bone loss

Increased risk of cancer and cardiovascular disease, yikes!

Statins increase bone mineral density

Paget’s Disease – haphazard and excessive bone deposit and resorption

High ratio of spongy to compact bone

Can cause spotty weakening of bone, pain, deformity (spine, pelvis, femur, skull)

Osteoclast activity wanes, but osteoblast activity continues

Possibly viral, 3% of Americans over 40

Treated with drugs, calcitonin