Bone Fractures Anatomy & Physiology

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

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 Hematoma formation

Stages in the Healing of a Bone Fracture Figure 5.5, step 2 Hematoma External callus New blood vessels Internal callus (fibrous tissue and cartilage) Spongy bone trabecula Hematoma formation Fibrocartilage callus formation

Stages in the Healing of a Bone Fracture Figure 5.5, step 3 Hematoma External callus Bony callus of spongy bone New blood vessels Internal callus (fibrous tissue and cartilage) Spongy bone trabecula Hematoma formation Fibrocartilage callus formation Bony callus formation

Stages in the Healing of a Bone Fracture Figure 5.5, step 4 Hematoma External callus Bony callus of spongy bone Healed fracture New blood vessels Internal callus (fibrous tissue and cartilage) Spongy bone trabecula Hematoma formation Fibrocartilage callus formation Bony callus formation 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 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

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