Bone Fracture Classification, Healing Mechanics, and Clinical Bone Scanning

Practice flashcards covering bone fracture types, fracture repair stages, healing durations, and clinical bone scan findings.

What defines a compression fracture of a bone?

A fracture in which the bone is squashed, which may occur in a vertebra during a fall.

What is a depressed bone fracture?

A fracture in which the broken part of the bone forms a concavity, such as in a skull fracture.

How is a displaced fracture defined?

A fracture in which the fractured bone parts are out of anatomic alignment.

What occurs in an epiphyseal fracture?

The epiphysis is separated from the diaphysis at the epiphyseal plate.

What is a greenstick fracture, and in which age group is it more commonly seen?

A partial fracture where one side of the bone breaks and the other side is bent; it is more commonly seen in children.

What is a hairline fracture?

A fine crack in which sections of bone remain aligned, commonly occurring in the skull.

What defines an impacted fracture?

A fracture in which one fragment of bone is firmly driven into the other.

How is an incomplete fracture characterized?

A partial fracture that extends only partway across the bone.

What is a linear fracture?

A fracture that is parallel to the long axis of the bone.

What characterizes an oblique fracture?

A diagonal fracture that is at an angle.

What causes a pathologic fracture?

A weakening of a bone caused by a disease process, such as cancer.

Where does a Pott fracture occur?

At the distal ends of the tibia and fibula.

What defines a simple (closed) fracture?

A fracture in which the bone does not break through the skin.

What causes a spiral fracture and how does it present?

It results from twisting stress and spirals around the axis of a long bone.

What is a stress fracture?

Thin fractures due to repeated, stressful impact such as running, which are often difficult to see on x-rays and may require a bone scan for identification.

What is a transverse fracture?

A fracture that is at right angles to the long axis of the bone.

What are the average healing times for a simple fracture in adults versus young children?

A simple fracture takes about 2 to 3 months to heal in adults, whereas the average healing time in young children is 3 weeks.

What is Step 1 in the bone fracture repair process?

A fracture hematoma forms from clotted blood caused by bleeding from torn blood vessels inside the bone and within the periosteum.

What occurs during Step 2 of bone fracture repair, and how long does this stage last?

A fibrocartilaginous (soft) callus forms as capillaries infiltrate the hematoma to form a procallus, where fibroblasts produce collagen fibers and chondroblasts form fibrocartilage; this stage lasts at least 3 weeks.

What occurs during Step 3 of bone fracture repair?

A bony (hard) callus forms within a week of injury as osteoprogenitor cells become osteoblasts and produce trabeculae of primary bone to replace the soft callus.

What occurs during Step 4 of bone fracture repair?

The bone is remodeled as osteoclasts remove excess bony material from exterior and interior surfaces for at least 3 to 4 months, and compact bone replaces primary bone.

How is a clinical bone scan conducted?

The patient is injected intravenously with a small amount of a radioactive isotope absorbed by bone, and a scanning camera measures the emitted radiation.

How does healthy bone tissue appear on a bone scan?

Healthy bone tissue shows an even distribution of gray coloring, with the axial skeleton typically appearing uniformly darker than the appendicular skeleton.

What do hot spots represent on a bone scan, and what conditions cause them?

Hot spots are focal darker areas indicating increased metabolism or greater tissue turnover, caused by conditions like stress fractures or cancer metastasis to bone.

What do cold spots represent on a bone scan, and what condition can cause them?

Cold spots are lighter areas indicating less metabolic activity of bone tissue, which may occur with avascular necrosis (death due to lack of blood supply).