Rad procedures aug 18

Anatomy and Physiology in Radiography

• Anatomy relates to the structure of the body, such as the images seen in typical X-rays.

• Physiology focuses on the process and the functions of how the body works.

• Both anatomy and physiology are utilized within the radiography field.

• Radiography can involve "live" X-rays, also known as video, to observe bodily functions in real-time.

Contrast Media and the Barium Swallow Exam

• To visualize anatomy that does not naturally show up on an X-ray, patients can be given contrast media.

• Contrast media is a liquid that absorbs X-ray photons, making specific structures visible.

• A common study is the barium swallow exam, also known as an esophagram.

• This exam is used for patients having difficulty swallowing liquids or food.

• In a neck X-ray, the spine is visible, but the esophagus and trachea are not. Providing contrast media allows the professional to monitor the function of the esophagus to ensure it is working properly.

Surgical Monitoring and Specialized Bone Types

• In certain Operating Room (OR) cases involving the spine or lower back, electrodes are hooked up to the patient.

• These electrodes monitor nerve proximity, signaling when a doctor is getting too close to a nerve.

• Sesamoid bones act like a pulley, allowing blood and signals to slide over cells. The most common location is at the base of the thumb.

• Sesamoid bones are also located at the base of the big toe. Injuries, such as falling from a ladder and landing on the foot, can result in a broken sesamoid bone.

• Radiographic exams can isolate these two bones at the distal part of the first metatarsal. They are classified as the tibial sesamoid bone and the fibular sesamoid bone, aligned with the tibia and fibula.

• Flat bones consist of two plates of compact bone with spongy cancellous bone in between. This highly porous area contains bone marrow for red blood cell production. Examples include:

  • The calvarium

  • The sternum

  • Ribs

  • The scapulae

Bone Growth and Development

• Bone growth occurs as bone replaces cartilage.

• Epiphyseal plates are the areas where bone growth happens as a child ages. On an X-ray, these appear as small lines near the ends of the bones.

• In adult bones, these areas fuse and look uniform; once fused, the individual is no longer growing.

• Fractures involving the epiphyseal plate are a significant concern as they can affect a child’s growth rate, leading to discrepancies, such as one leg growing at a different rate than the other.

• Patients with epiphyseal fractures are often referred to pediatric hospitals, such as Shriners.

• The metaphyses are the areas near the ends of long bones where the body of the bone starts to widen.

Functional and Structural Joint Classifications

• Functional classifications include:

  • Synarthrosis: Immovable joints. The prefix "syn-" means in, together, or combined.

  • Amphiarthrodial: Slightly movable joints.

  • Diarthrodial: Freely movable joints.

• Structural classifications include:

  • Fibrous joints: Lacked a joint cavity; held together by fibrous connective tissue.

    • Syndesmosis: Slightly movable ($amphiarthroidal$).

    • Sutures: Immovable ($synarthroidal$).

    • Gomphosis: Limited movement; found at the roots of the teeth.

  • Cartilaginous joints: Lack a joint cavity.

    • Symphysis: A broad, flat disc of fibrocartilage (e.g., intervertebral discs or the joint between hip bones).

    • Synchondrosis: A temporary joint, such as the epiphyseal plates, which fuse in adulthood.

  • Synovial joints: Contain a joint capsule with synovial fluid.

Types of Synovial Joints and Examples

• Plane (Gliding): Permits the least amount of movement. Examples: Carpal-metacarpal joints (moving like two sheets of paper gliding).

• Ginglymus (Hinge): Permits flexion and extension. Examples: Interphalangeal joints of the fingers and the elbow joint.

• Trochoid (Pivot): Permits rotational movement. Examples: The C1-C2 cervical vertebrae (where C1 pivots around the odontoid process) and the proximal and distal radius and ulna during supination.

• Ellipsoid (Condyloid): Permits flexion, extension, abduction, adduction, and circumduction. Examples: Metacarpophalangeal joints and the radiocarpal (wrist) joint.

• Sellar (Saddle): Features a concave and convex surface fitting together like a rider on a horse. Permits flexion, extension, abduction, adduction, and circumduction. Example: The first carpal-metacarpal (CMC) joint of the thumb.

• Spheroidal (Ball and Socket): Permits lateral rotation, flexion, extension, abduction, adduction, and circumduction. Examples: Hip joint and shoulder joint.

• Bichondylar: Involves two distinct surfaces on articulating bones involving a condyle. Examples: Temporomandibular joint (TMJ) and the knee.

Radiographic Projections and Terminology

• AP (Anterior to Posterior): The X-ray beam hits the anterior surface and exits the posterior surface.

• PA (Posterior to Anterior): The X-ray beam hits the posterior surface and exits the anterior surface.

• Projection refers to the path of the X-ray beam as it projects through the patient.

• The Bucky is the holder that contains the cassette or image receptor (IR). It was named after a doctor who created the holder.

• Image Receptor (IR): The device that captures the image. Modern IRs are digital and computerized.

• History of IRs:

  • Traditional film involved taking a cassette into a dark room and using chemicals.

  • Computed Radiography (CR) used an imaging plate inside a cassette that was read by a machine.

  • Digital Radiography (DR) uses computerized cassettes with batteries. These are highly expensive—costing as much as a Corvette—and contain sensors that register if they have been dropped.

X-Ray Equipment and the Central Ray

• The X-ray tube is where the X-rays are generated.

• A typical room has two buckies: an upright wall bucky and one underneath the table. Some modern buckies are built-in and lack a removable cassette, which limits flexibility for patients who cannot move easily.

• Alignment is critical: the X-ray tube must be lined up with the patient's anatomy (e.g., the iliac crest) and the bucky/cassette simultaneously to capture an image.

• Divergence of the beam: The beam spreads out like a water hose in a cone shape as it exits the tube.

• Central Ray (CR): The very center of the beam where there is the least amount of distortion. Exams specify where the CR should be directed for accuracy.

Body Habitus and Positioning

• Body habitus refers to the general style of a person’s build and determines technical factors used at the control console (kilovolts and mass).

• Four General Styles:

  • Sthenic: Average build, comprising approximately $50\%$ of the population.

  • Hyposthenic: Thin or smaller than average.

  • Hypersthenic: Larger body frame. Features shorter and wider lungs.

  • Asthenic: Very thin with a long, narrow body build. Features longer and narrower lungs.

• Cassette orientation terms are shifting toward digital terminology: Portrait (lengthwise) and Landscape (crosswise).

• Anatomic Position: Body standing upright, palms forward, and toes forward.

• Surface Terminology:

  • Posterior/Dorsal: The back surface.

  • Anterior/Ventral: The front surface.

  • On the feet and hands, the bonier surface is considered the dorsal surface.

Radiographic Procedures and Safety

• The positioning process includes: positioning the part, aligning it to the anatomy, and ensuring the central ray is lined up to the IR.

• Radiation Protection: Lead shields are used, but their application is now specialized. If a shield is too close to the primary beam, photons can bounce under the shield, potentially doubling the radiation dose to the patient. They are recommended by the ARRT and ASRT as long as they are not near the primary beam.

• Computed Tomography (CT): A machine shaped like a doughnut with multiple tubes and receptors that spin around the patient. It takes "slices" of images that can be reconstructed into a 3D image, similar to a loaf of bread.

• Planes of the Body:

  • Sagittal Plane: Cuts the anatomy into left and right sides.

  • Coronal Plane: Cuts the anatomy into front and back sides.

  • Base Plane: The plane from the infraorbital margins (below the eyes).

Questions & Discussion

Question: What is the IR? Response: That is the image receptor. It is the device that captures the image. There are many different types, but facilities have moved toward digital equipment because Medicare stopped reimbursing those not using digital systems about ten years ago.

Question: Does "syn-" relate to synesthesia? Response: Yes, synesthesia involves combined senses. In joints, the prefix "syn-" means combined or together, representing immovable joints.