Science: Systematized and classified knowledge.
ology: (suffix). A science or branch of knowledge.
Regional or topographical anatomy: The study of separate parts of the body.
Systemic anatomy: The study of systems and associated parts. Systemic anatomy is divided into these subdivisions:
Osteology - the study of the bones.
Arthrology - The study of the articulations or joints.
Myology - The study of the muscular system.
Neurology - The study of the nervous system.
Angiology - The study of the vascular/lymphatic vessels.
Embryology: The study of the origin of the structures of the body.
Physiology: The study of the functions and activities of the body.
Pathology: The study of changes in the structures or function of the body caused by disease or trauma.
Radiology: That branch of medical science that deals with the use of radiant energy in the diagnosis and treatment of injuries and diseases.
Normal Anatomical Position
To avoid misunderstanding, a standard position of the human body is arbitrarily taken to be the erect (standing) position with feet flat on the floor, heels together, upper extremities at the sides, and palms, toes, and eyes directed forward. This is the anatomical position.
Terms Dealing with Aspects and Directions
Anterior, frontal, or ventrum: The front side of the body.
Posterior or dorsum: The back, or dorsum, of the body.
Median: Pertaining to the midline of the body.
Lateral: Away from the midline or lateral side of the body. In the forearm, the ulna is medial to the radius and the radius is lateral to the ulna. The thumb is on the lateral aspect of the hand.
Proximal: Nearest to a point under consideration or the point of origin. In the case of the extremities, the articulations are considered points of origin
Distal: Remoteness from a point under consideration or the point of origin; the opposite of proximal. In the case of the extremities, joints are considered points of origin.
Cephalic: Toward the head.
Caudad: Toward the feet.
Radiographic Usage of Certain Terms
In diagnostic X-ray services, such terms as anteroposterior (AP) or posteroanterior (PA) are frequently used. The prefix indicates the surface from which the central ray (CR) enters the part and the suffix indicates the surface from which the CR emerges.
Planes of the Body
*Sagittal plane: Any vertical plane that divides the body into right and left unequal portions.
*Median or midsagittal plane: The vertical plane that divides the body into right and left halves.
*Frontal or coronal plane: Vertical plane that divides the body into front and rear portions.
*Transverse or horizontal plane: Any horizontal plane that divides the body into upper and lower portions. The level of this plane must be given.
Surfaces of the Hands and Feet
*Palmar surface: Anterior surface (palm) of the hand.
*Volar surface: Anterior surface of the hand and forearm (or the sole of the foot).
*Plantar surface: Inferior surface (sole) of the foot.
*Dorsal surface: Top or superior surface (dorsum) of the foot.
Terminology Relating to the Positions of the Body
Supine: A horizontal position of the body lying flat on the back with no rotation of the trunk.
Prone: A horizontal position of the body lying face and stomach down with no rotation of the trunk.
Lateral recumbent: A horizontal position of the body lying on either side with no rotation of the trunk.
Oblique: A position of the body, or any of its parts, when placed at an inclined angle to the X-ray film.
Erect or vertical: A position of the body either sitting or standing.
External and Internal
These terms are used to describe locations with respect to the surface.
Four terms are generally used to designate the four major types of body habitus. Since the position of certain organs (for example, the gallbladder) can vary as much as 6 to 8 inches between body types, it is essential that the X-ray specialist be familiar with these major body types:
The hypersthenic body is of massive build with a broad and deep thorax. The diaphragm is high and the stomach and gallbladder also occupy high positions. An extreme body type, the hypersthenic classification accounts for only about five percent of all people.
Means active or strong. The sthenic body is the one we usually associate with the athletic type. The body is rather heavy with large bones. The sthenic body type is the predominant type, with about half of all people falling into this classification.
Slender and light in weight with the stomach and gallbladder situated high in the abdomen. About 35 percent of all people fall into this classification.
Extremely slender, light build, with a narrow, shallow thorax, and the gallbladder and stomach situated low in the abdomen. An extreme type, the asthenic classification accounts for only about ten percent of all people.
Regions of the Abdomen
The abdomen is that portion of the body that lies between the thorax and the pelvis. It consists of a large cavity, separated from the thoracic cavity by the diaphragm, bounded by muscles and fascia, and partially lined with a serous membrane called the peritoneum.
For purposes of description, the abdomen is divided into nine regions by means of two horizontal and two vertical lines. The upper horizontal line passes through the tenth costal cartilage inferiorly. The lower line passes through the level of the iliac tubercle. Each vertical line passes through the midpoint of a line drawn from the anterior superior iliac spine to the symphysis pubis.