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Glossary of Terms

| A | B | C | D | H | I | J | K | L | M | N | P | R | S | U | V |

A

abdomen: The belly , that part of the body that contains all of the structures between the chest and the pelvis . The abdomen is separated anatomically from the chest by the diaphragm , the powerful muscle spanning the body cavity below the lungs.

anatomy: The study of form. Gross anatomy involves structures that can be seen with the naked eye. It is as opposed to microscopic anatomy (or histology) which involves structures seen under the microscope. Traditionally, both gross and microscopic anatomy have been studied in the first year of medical school in the U.S. The most celebrated textbook of anatomy in the English-speaking world is Gray's Anatomy, still a useful reference book. The word "anatomy" comes from the Greek ana- meaning up or through + tome meaning a cutting. Anatomy was once a "cutting up" because the structure of the body was originally learned through dissecting it, cutting it up. The abbreviation for anatomy is anat.

aneurysm: A localized widening (dilatation) of an artery, vein, or the heart. At the area of an aneurysm, there is typically a bulge and the wall is weakened and may rupture. The word "aneurysm" comes from the Greek "aneurysma" meaning "a widening."

angiography: A procedure performed to view blood vessels after injecting them with a radioopaque dye that outlines them on x-ray . This technique can be usefully used to look at arteries in many areas of the body, including the brain, neck ( carotids ), heart , aorta , chest , pulmonary circuit, kidneys , gastrointestinal tract, and limbs.

ankle: The ankle joint is complex. It is made up of two joints: the true ankle joint and the subtalar joint.

arm: 1. In popular usage, the appendage that extends from the shoulder to the hand. However, the medical definition refers to the upper extremity extending from the shoulder only to the elbow, excluding the forearm, which extends from the elbow to the wrist. The arm contains one bone: the humerus. 2. In a randomized clinical trial, any of the treatment groups. Most randomized trials have two "arms," but some have three "arms," or even more.
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B

bone: Bone is the substance that forms the skeleton of the body. It is composed chiefly of calcium phosphate and calcium carbonate . It also serves as a storage area for calcium, playing a large role in calcium balance in the blood.

brain: That part of the central nervous system that is located within the cranium ( skull ). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."

brain aneurysm: A brain aneurysm is a small outpouching (an aneurysm) that looks like a berry and classically occurs at the point at which a cerebral artery departs from the circular artery (the circle of Willis) at the base of the brain. Berry aneurysms are prone to rupture and bleed. Also called a berry aneurysm. ____________________________________________

C

cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).

carotid: Pertaining to the carotid artery and the area near that key artery located in the front of the neck though which blood from the heart goes to the brain.

cartilage: Firm, rubbery tissue that cushions bones at joints. A more flexible kind of cartilage connects muscles with bones and makes up other parts of the body, such as the larynx and the outside parts of the ears.

claustrophobia: An abnormal and persistent fear of closed spaces, of being closed in or being shut in, as in elevators, tunnels, or any other confined space. The fear is excessive (and quite common).

contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.

CT scan: Computerized tomography scan. Pictures of structures within the body created by a computer that takes the data from multiple X-ray images and turns them into pictures on a screen. CT stands for computerized tomography.
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D

dilatation: The process of enlargement or expansion.
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H

heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.

herniation: Abnormal protrusion of tissue through an opening. For example, a intervertebral disk (one situated between the vertebral bodies) can protrude and impinge on a nerve root.
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I

intravenous pyelogram: An x-ray of the kidneys and urinary tract. Structures are made visible by the injection of a substance that blocks x-rays. Also called IVP.
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J

joint: A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint.
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K

knee: The knee is a joint which has three parts. The thigh bone (the femur) meets the large shin bone (the tibia) to form the main knee joint. This joint has an inner (medial) and an outer (lateral) compartment. The kneecap (the patella) joins the femur to form a third joint, called the patellofemoral joint. The patella protects the front of the knee joint.
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L

leg: In popular usage, the leg extends from the top of the thigh down to the foot. However, in medical terminology, the leg refers to the portion of the lower extremity from the knee to the ankle.

liver: An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.
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M

Magnetic resonance imaging : A special radiology technique designed to image internal structures of the body using magnetism, radio waves, and a computer to produce the images of body structures. In magnetic resonance imaging (MRI), the scanner is a tube surrounded by a giant circular magnet. The patient is placed on a moveable bed that is inserted into the magnet. The magnet creates a strong magnetic field that aligns the protons of hydrogen atoms, which are then exposed to a beam of radio waves. This spins the various protons of the body, and they produce a faint signal that is detected by the receiver portion of the MRI scanner. A computer processes the receiver information, and an image is produced. The image and resolution is quite detailed and can detect tiny changes of structures within the body, particularly in the soft tissue, brain and spinal cord, abdomen and joints.

MRA:The magnetic resonance angiogram, or MRA, is a noninvasive test that has demonstrated usefulness in defining the anatomy of blood vessels of certain size in the head and neck. MRA serves as a complement to traditional MRI scanning in evaluation of the brain and neck.

MRCP: Magnetic resonance cholangiopancreatography, an application of MRI ( magnetic resonance imaging ) to the hepatobiliary and pancreatic system. An MRCP uses an MRI machine with special software to obtain images comparable to the cholangiogram and pancreatogram obtained by the more invasive approach with ERCP (endoscopic retrograde cholangiopancreatography) without the added risks of sedation, pancreatitis , and perforation.

MRI: Abbreviation and nickname for magnetic resonance imaging . ____________________________________________

N

neck: The part of the body joining the head to the shoulders. Also, any narrow or constricted part of a bone or organ that joins its parts as, for example, the neck of the femur bone.

nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another.
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P

pancreas: A fish-shaped spongy grayish-pink organ about 6 inches (15 cm) long that stretches across the back of the abdomen, behind the stomach. The head of the pancreas is on the right side of the abdomen and is connected to the duodenum (the first section of the small intestine). The narrow end of the pancreas, called the tail, extends to the left side of the body.

pelvic: Having to do with the pelvis, the lower part of the abdomen, located between the hip bones.

pelvis: The lower part of the abdomen located between the hip bones.

prostate: A gland within the male reproductive system that is located just below the bladder. Chestnut shaped, the prostate surrounds the beginning of the urethra, the canal that empties the bladder.

prostate cancer: An uncontrolled (malignant) growth of cells in the prostate gland which is located at the base of the urinary bladder and is responsible for helping control urination as well as forming part of the semen. Prostate cancer is the second leading cause of death of males in the U.S.

pyelogram: X-ray study of the kidney especially showing the pelvis (urine-collecting basin) of the kidney and the ureter.
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R

Radiologist: A physician specialized in radiology , the branch of medicine that uses ionizing and nonionizing radiation for the diagnosis and treatment of disease.
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S

scan: As a noun, the data or image obtained from the examination of organs or regions of the body by gathering information with a sensing device.

spinal stenosis: Narrowing of the spaces in the spine, resulting in compression of the nerve roots or spinal cord by bony spurs or soft tissues, such as disks, in the spinal canal. This occurs most often in the lumbar spine (in the low back) but also occurs in the cervical spine (in the neck) and less often in the thoracic spine (in the upper back).

spine: 1) The column of bone known as the vertebral column, which surrounds and protects the spinal cord. The spine can be categorized according to level of the body: i.e., cervical spine (neck), thoracic spine (upper and middle back), and lumbar spine (lower back). See also vertebral column. 2) Any short prominence of bone. The spines of the vertebrae protrude at the base of the back of the neck and in the middle of the back. These spines protect the spinal cord from injury from behind.

stenosis: A narrowing, as in: aortic stenosis (narrowing of the aortic valve of the heart); pulmonary stenosis (narrowing of the pulmonary valve of the heart); pyloric stenosis (narrowing of the outlet of the stomach); and spinal stenosis (narrowing of the vertebral canal).
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U

ultrasound : High-frequency sound waves. Ultrasound waves can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques. Ultrasound is often used to examine a fetus during pregnancy . There is no convincing evidence for any danger from ultrasound during pregnancy. ____________________________________________

V

vein: A blood vessel that carries blood low in oxygen content from the body back to the heart. The deoxygenated form of hemoglobin (deoxyhemoglobin) in venous blood makes it appear dark. Veins are part of the afferent wing of the circulatory system which returns blood to the heart.

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