Radiographic Anatomy RAD 242 Prepared By: Ala’a Ali Tayem Abed

Introduction to Anatomy, Physiology, and Radiological Terminology

Introduction to Anatomy and Physiology The terms anatomy and physiology 1. Anatomy—The scientific study of the structure of an organism that describes the size, shape, construction, and relative positions of the organs in the body. 2. Physiology—The scientific study of the functions of an organism that describes how the organs work independently and in relation to the whole organism. 3. Anatomical Position—A position of the body in which a person stands erect, facing directly forward, feet pointed forward and slightly apart, arms hanging down at the sides with the palms facing forward; a standard method of viewing the body so that the anatomy can be consistently described.

Three standard views provide perspectives of the anatomical position:

Common body planes: The five common body planes: 1. Median Plane. 2. Sagittal Plane. 3. Coronal Plane. 4. Transverse Plane. 5. Oblique Plane.

X-ray Anatomy. Radiologic Anatomy: X-ray Anatomy. X-ray Anatomy: study of organs and tissues based on their visualization by x-rays in both living and dead bodies.

General Principles X-rays are the beam of ionizing radiation emitted from the X-ray tube during the exposure. Although, “X-ray” is a term frequently used to refer to the image/film produced, radiograph is the correct term. The radiograph, irrespective of the projection/view, is a 2-dimensional representation of a 3-dimensional structure. The image produced is therefore made up of multiple overlying structures. Accurate localization of an abnormality frequently requires two radiographs obtained at right angles to one another e.g. anteroposterior (AP) and lateral projections. Remember that an object visible on a radiograph may be situated anywhere between the X-ray tube and the film cassette.

 structures of high density (e.g. bones and metal foreign bodies) will absorb (attenuate) the X-ray beam more than structures of low density (e.g. soft tissues and air). — bones will appear white. — soft tissues will appear grey. — air/gas will appear black.  When the density of a structure is too similar to that of adjacent structures, it is possible to use contrast media to enhance or outline its contours. Contrast media are classified as radiolucent (e.g., air) and radio-opaque (e.g., barium or iodinated contrast media).  Barium and/or air can be used to highlight the lumen of the gastrointestinal tract.  Iodinated contrast media can be administered intravascularly to view arteries (arteriogram), or veins (venograms), and intrathecally to outline the spinal cord and nerve roots.

Lateral radiograph of the knee of an adult who had been shot with an air gun. bones (femur, tibia and patella) = white. muscles = grey. air in front and behind knee = black. rounded white object behind distal femur is a foreign body (air gun pellet). the angular objects around the pellet are also foreign bodies. They are metallic staples applied to the skin to show the site of the entry wound. the black linear shadows adjacent to the pellet represents air introduced at the time of injury.

AP radiograph of the hip. The multiple rounded white abnormalities are not in but on the patient, due to at least 10 overlapping coins in the pocket of the trousers that should have been removed prior to the X-ray examination. Chest radiograph. The abnormality is what is NOT present on the film. The whole right upper limb and shoulder girdle have been surgically removed as treatment for an advanced sarcoma.

Positions and Projections: The views or positions used in plain radiographic images are named for the part of the body that is nearest the film, for example, anterior, right lateral, left anterior oblique. Alternatively, Projections, the terms anteroposterior and postero-anterior are used when the x-rays have passed through the object from front to back (tube in front of object, film behind) or from back to front (tube behind object, film in front), respectively.

Terminology: As with any technical subject, there are numerous terms used to describe the different appearances on a radiograph. sclerotic — increased bone density. demineralization — decreased bone density (as occurs with Osteomalacia/ Osteopenia/ Osteoporosis). lytic — bone destruction. cortex — compact (dense) bone forming the bone surface. medulla — trabecular bone in the bone marrow. articular — refers to a joint (an articulation). ankylosis — stiffness. osteo- — prefix meaning bony (e.g. Osteosarcoma). chondro- — prefix meaning cartilaginous (e.g. Chondrosarcoma). fibro- — prefix meaning fibrous (e.g. Fibrosarcoma). arthro- — prefix meaning joint (e.g. Arthritis). spondylo- — prefix meaning spinal (e.g. Spondyloarthropathy). dactyl- — prefix meaning digit (either finger or toe, e.g. Dactylitis).

For description of radiographic projections and positions, the following terms are often helpful: Anterior (Ventral). Posterior (Dorsal). AP — Anteroposterior. PA — Posteroanterior. Superior. Inferior. Medial. Lateral — from the side. Oblique — between lateral and AP (or PA). Decubitus — lying horizontal. Supine — lying on the back. Prone — lying face down. Erect — standing. Axial — along the axis (of an anatomic structure). Cephalic — towards the head. Caudal — towards the feet. Proximal. Distal. Superficial. Deep. Peripheral.

Positioning Lines - Landmarks

External Landmarks