X-ray Lab

Identifying X-Rays

HASPI Medical Anatomy & Physiology 08d Activity

 Background

Radiography

Medical radiography is the visualization and study of parts of the body using x-rays.  The terms x-ray and radiograph are interchangeable.  In 1895, German scientist Wilhelm Roentgen accidentally discovered the ability of an x-ray pulse to pass through the human body and create an image on a screen.  There have been many improvements since then, especially once the lower-energy x-rays were found to be extremely harmful to human body tissues. 

Modern x-ray machines send electron beams through the soft tissue of the body and are blocked by denser bone and tissues.  What is left after the electron beam passes through the body is captured on a film, or more commonly a receiver, that creates a digital x-ray.  X-rays are able to pass through the human body but are slowed down by denser material, like the calcium in bones.  X-rays are primarily used to diagnose injury or disease to bones, joints, and internal organs. 

Radiography is one of the most common diagnostic tests performed, and in 2010 more than 5 billion radiographs were taken in the U.S.  There are many different types of radiographs, or images, that can be taken depending on the part of the body being viewed.  Some of the most common examples include:

• Musculoskeletal radiographs used to diagnose fractures or dislocations
• Chest radiographs used to diagnose lung diseases like pneumonia
• Fluoroscopy during heart catheterization procedures
• Fluoroscopy used to diagnose disorders or blockage of the GI tract
• Mammograms
• Dental radiographs

Dislocation & Bone Fractures

The dislocation of a joint is a common musculoskeletal trauma diagnosed through radiography.  Dislocation is the displacement of bones at the joint, and is often caused by impact trauma to that joint.  Dislocations can often be more damaging and painful than fractures, since damage of the joint capsule and surrounding ligaments and tendons often take much longer to heal than bone tissue due to lack of vascularization.

http://www.fdmadison.org/uploads/images/health/dislocation.gif 

Fractures are a common occurrence and result when a physical force that is greater than the strength of the bone is exerted.  On average, everyone will experience at least two fractures in their lifetime.  Some general terms in reference to fractures are displaced, non-displaced, closed/simple, and open/compound.  A displaced fracture occurs when the bone breaks and the ends no longer line up straight, while in a non-displaced fracture the bones still line up straight.  A closed or simple fracture stays within the skin, while an open or compound fracture breaks through the skin surface.  In addition to these terms, there are many different types of fractures that are categorized based on how the bone actually breaks. 

Types of Fractures

The type and severity of a fracture is dependent on the strength and direction of the forces that cause a bone to break.  The following table summarizes the common types of fractures and the type of force that could be the cause.  The image below shows a visual of each fracture type.

http://askabiologist.asu.edu/sites/default/files/resources/activities/body_depot/busy_bones/bone_fractures.gif