bone fractures anatomy & physiology. how do bones fracture? trauma directly to the bone...

Bone Fractures

Anatomy & Physiology

How Do Bones Fracture?How Do Bones Fracture?

• Trauma Directly to the bone (impact, tension, or

compression) Bending the two ends of the bone

toward each other Twisting the bone (torsion)

Classification of Fractures

• Simple closed

• Compound bone protrudes

through the skin

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are needed to see this picture.

Fracture Types

• Greenstick fracture

• Transverse fracture

• Oblique fracture• Comminuted

fracture• Spiral fracture• Compression

fracture

Greenstick Fracture

•An incomplete fracture in which the bone is bent

•This type occurs most often in children





Transverse Fracture

• At a right angle to the bone's axis

• Like a cross section





Oblique Fracture

A slanted fracture of the shaft along the bone's long axis





Comminuted Fracture

The bone fragments or is crushed into several pieces





Spiral Fracture

• A fracture in which the bone has been twisted apart and the line of break is helical

• Sometimes called torsion fracture





Compression Fracture

• The front portion of a vertebra collapses

• Especially in a short bone, it disrupts osseous tissue and collapses the affected bone



How Does a Bone Heal?

• Immediately following a break, the body starts to repair the injury

1. Hematoma forms (Area swells due to influx of extra oxygen and nutrients)

2. Fibrocartilage callus forms

Osteoprogenitor cells go from dividing every few days to every few minutes

New connective tissue forms a soft callus, which hardens around the break over several months

How Does a Bone Heal?

3. Bony callus forms • Sufficiently mineralized to show up on an x-ray

within 6 weeks• Initial "woven" bone does not have the strength

of mature bone

4. Bone remodeling Through remodeling, the woven bone is

replaced by mature "lamellar" bone Whole process can take up to 18 months, but in

adults the strength of the healing bone is usually 80% of normal by 3 months after the injury

Stages in the Healing of a Bone Fracture

Figure 5.5, step 1

Hematoma

Hematomaformation


Figure 5.5, step 2

Hematoma

Externalcallus

Newbloodvessels

Internalcallus(fibroustissue andcartilage)

Spongybonetrabecula

Hematomaformation

Fibrocartilagecallus formation


Figure 5.5, step 3

Hematoma

Externalcallus

Bonycallus ofspongybone

Newbloodvessels


Spongybonetrabecula

Hematomaformation


Bony callusformation


Figure 5.5, step 4

Hematoma

Externalcallus

Bonycallus ofspongybone

Healedfracture

Newbloodvessels


Spongybonetrabecula

Hematomaformation


Bony callusformation

Bone remodeling

Limb Lengthening

•Used to replace missing bone and lengthen and/ or straighten deformed bone segments

•May be performed on both children and adults who have limb length discrepancies due to birth defects, diseases or injuries

Limb Lengthening

• In this process, a bone that has been cut during surgery can be gradually distracted (pulled apart), leading to new bone formation (osteogenesis) at the site of the lengthening.

•Bone segments can be lengthened by 15 - 100 percent of original length

Limb Lengthening

•The regenerated bone is normal and does not wear out

•The muscles, nerves and blood vessels grow in response to the slow stretch like they do during a growth spurt or in pregnancy

Limb Lengthening Video 1



bone fractures anatomy & physiology. how do bones fracture? trauma directly to the bone...

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