A condition in which a cell or a group of cells dedifferentiate and enters into an immature stem cell-like phase – meaning the cell lost its distinct structural and functional differentiation. Anaplasia is a constant feature of malignancies (e.g., Leiomyosarcoma, Adenoma, and Adenocarcinoma).
a = without, not, or no;
-plasia = formation, growth
A developmental failure resulting in the absence of all or part of an organ or tissue. In most cases, aplasia is congenital however, certain types may sometimes not be apparent until a certain age.
dys = bad, difficult, painful, or disordered
-plasia = formation, growth
In embryology and developmental biology, dysplasia is an abnormal growth and differentiation of tissues or organs. In oncology, it is used to describe atypical or disordered growth of cells; these cells may become cancer precursors.
hyper = excessive, beyond;
-plasia = formation, growth
An abnormal proliferation or increase in the number of cells that increases the size of a tissue or organ. For example, breast glandular epithelium hyperplasia, compensatory hyperplasia of the liver, and benign prostatic hyperplasia.
hypo = under, below, beneath, less than normal;
-plasia = formation, growth
Underdevelopment or incomplete development of a tissue or an organ, usually the result of a decrease in the number of cells. Hypoplasia can occur in many different areas of the body such as enamel, thumb, bone marrow, cerebellum, testes and ovaries, and optic nerve.
neo = new
plasia = formation, growth
The new, uncontrolled growth of cells. Neoplasms can be (i) benign growths such as skin moles, cysts, and fibroids, (ii) cancer, or (iii) pre-cancerous tumors.
The standard reference point for anatomical nomenclature (e.g., anterior and posterior, medial and lateral, cranial and caudal, or proximal and distal). The position with the body erect, the arms held out to each side and the palms forward; the feet at shoulder width, and toes pointing forward.
The imaginary line down the middle of the body that cuts the body into equal left and right halves.
Denotes the front side (chest) of the body, or towards the abdomen. For example, the kneecap is anterior to the leg. The term is also used in combination with other words to describe the location of a body part. For example, the belly button is described as anterior, mid-abdominal, i.e. it is located on the front in the middle of the abdomen.
Denotes the back of the body. Any body part that is not pictured in the Vitruvian man diagram, is likely a posterior part. For example, shoulder blades, sole, popliteus, etc.,
Ventr/o = belly; equivalent to the anterior or front side of the body
-al = pertaining to
The ventral side of the body includes the chest, abdomen, shins, palms, and soles.
The ventral cavity in the human body is a fluid-filled space at the anterior side, housing visceral organs.
Dors/o = back; equivalent to the posterior or backside of the body
-al = pertaining to.
Examples are the back, buttocks, calves, and knuckles.
medius = middle. Medi/o = middle;
-al = pertaining to
Refers to being toward the midline or the median plane, which splits the body, head-to-toe, into two halves, the left and right. For example, the torso is medial to the arms.
later/o = belonging to the side, -al = pertaining to
Side or part of the body that is away from the midline. For example, the arms are lateral to the torso.
Medi/o = middle, later/o = side, -al = pertaining to
Refers to the axis from the medial side and extends out the lateral side; used to describe relative position of the side or part of the body along the left-right axis.
Refers to the body’s vertical axis; any body part that is higher than another or above it is said to be superior to it. For example, the head is superior to the neck and the torso is superior to the legs. Also used to denote organs toward the head.
Any body part that is lower than another or below it is said to be inferior to it. For example, the liver is inferior to the lungs. Also, used to denote organs at the caudal or lowermost regions of the body.
Crani/o = skull
-al = pertaining to.
Denoting cranium, or the skull.
Denoting tail, or hind/posterior part of the body.
Refers to parts of the body away from the trunk or center of the body. For example, the wrist joint is distal to the elbow. The distal bile duct is the farthest end of the cystic duct, away from the gallbladder.
Proxim/o = near; -al = pertaining to
Toward or nearer to the trunk or center of the body, or nearer to the point of attachment or origin. For example, the femur is proximal to the knee. Similarly, the shoulder is proximal to the elbow.
In anatomy, ‘Superficial’ and ‘Deep’ are the directional terms used in reference to the position of tissues and organs. ‘Superficial’ denotes the structures closer to the surface of the body whereas ‘Deep’ denotes structures farther from the surface and toward the inside of the body. For example, the skin is superficial, while the bones and spine are deep in the body.
Lying on the back, faceup; the most common position used during intracranial, cardiac, abdominal, gynecological, endovascular, laparoscopic, rectal, and urologic procedures.
One of the movements occurring at the proximal radioulnar joint. When the palm faces up or forward, it’s supinated. Supination occurs in functional activities such as feeding, washing the face, turning the hand to receive something, or holding a bowl of water.
Lying on the stomach with the limbs unextended and head turned to one side; an ideal position for therapeutic massage, back surgeries, and various biopsies.
When the palm faces down or backward, it’s pronated. Grabbing an object, turning a screwdriver, or rotating a screwdriver are some examples of pronation.
Hypothetical geometric lines that cut through and section an upright body; used as reference points to describe direction and location of bodily parts.
Frontal plane
The frontal or coronal plane, the vertical plane that cuts the body into front (anterior) and back (posterior) sections.
Transverse plane
A horizontal plane that divides the body into superior (upper) and inferior (lower) portions. In anatomical studies, they are also referred to as a cross-section.
Midsagittal plane
A sagittal plane that bisects the body vertically through the midline, separating the right and left halves.
Denotes the sole or bottom of the foot.
Plantar flexion
Downward movement of the foot; allows one to walk, run, dance, or pedal.
-abdomin/o = abdomen, -al = of the abdomen
The largest body cavity beneath the thoracic cavity and above the pelvic cavity; holds the major viscera including the greater part of the digestive tract, liver, pancreas, gallbladder, spleen, kidneys, colon, and rectum.
Abdominopelvic cavity
A collective term for abdominal and pelvic cavities; anatomically, it is divided into four quadrants (left upper quadrant (LUQ), left lower quadrant (LLQ), right upper quadrant (RUQ), and right lower quadrant (RLQ).
abdomin/o = abdomen
pelv/i =pelvis
-ic = pertaining to
Cardi/o – = heart, -ac = related to
The cardiac muscle or myocardium is the muscle of the heart. This involuntary, striated muscle is responsible for coordinated contractions, letting the heart pump blood.
From Latin cella = small room.
The smallest unit of life; some cells are organisms unto themselves (e.g., unicellular bacteria and protozoa); others are structural or functional units of multicellular organisms (e.g., plants and animals).
Cell membrane
Cell membrane, also called the plasma membrane, the thin semi-permeable outer covering of a cell. It acts as a gate to control the transportation of materials between the cytoplasm and the external environment.
Cervic/o = the neck or the nape of the neck, -al = pertaining to
The first seven stacked bony rings of the spinal column; labeled as C1 through C7. Despite being the most delicate bones, cervical vertebrae do the jobs of supporting the skull, protecting the spinal cord, and providing mobility to the head.
Microscopic, organized bundles of tightly coiled DNA found in the nucleus of the cell; carries hereditary information as genes.
The tailbone; the terminal part of the vertebral column, representing a vestigial tail in humans. Comprising three to five coccygeal vertebrae, it serves as the attachment point for multiple muscles, ligaments, and tendons. The coccyx also provides weight-bearing support when in a seated position.
A group of tissues that support and bind other tissues in the body; also acts as a ‘filler’ for areas not occupied by other tissue. There are three main groups of connective tissues: Loose connective tissue (holds organs in place), Dense connective tissue (helps attach muscle to bones and links bones at their joints), and Specialized connective tissue (adipose, cartilage, bone, blood, and lymph)
Crani/o = skull, -al = pertaining to.
Denoting the skull or cranium.
Cranial cavity
crani/o = skull, -al = pertaining to
The cranial cavity, or intracranial space, houses and protects the brain, its meninges, and vasculature.
Greek kytos = hollow receptacle or container.
cyt/o = cell; -logy = study of.
Study of individual cells, their origin, structure, function, and pathology.
Cytoplasm
cyt/o = cell;
-plasm = living substance or substance of a cell
A jelly-like substance that fills each cell. It contains organelles, including the nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, and mitochondria.
Epi- = above;
-gastric = denoting stomach.
One of the abdominal regions, located between the left and right hypochondriac region; above the belly and below the ribcage. Parts of the right and left lobes of the liver and a major portion of the stomach come under the epigastric region.
Densely packed tissues lining the internal and external organs; it also lines the vessels, body cavities, glands, and hollow organs.
Based on the number of layers that make up the epithelium, it is classified as simple, stratified, and pseudostratified. Histologists classified epithelial tissue, according to the cell shape: squamous, columnar, and cuboidal.
A short segment of DNA that codes, or holds instructions for proteins.
hist/o = tissue; – logist = one who studies or specializes, an expert.
A histology specialist
Hypo = below, beneath, under; chondr/i = cartilage; -ac = pertaining to
A region on either side of the upper abdomen, under the cartilages of the false ribs, beside the epigastric region, and above the lumbar region. Includes the gallbladder and the right lobe of the liver.
Hypo = below, beneath, under; gastr/o = stomach, abdomen, -ac = pertaining to
The region below the umbilical region. Includes the urinary bladder, portions of the small intestine, and the appendix.
inguin/o = groin, -al = pertaining to
The groin, or lower lateral sections of the abdomen; also called the iliac region. In males, it is a site for herniations.
Lumb/o = loin, lower back, -ar = pertaining to
Also referred to as the lower spine; a region between the hypochondriac and iliac regions, and outside of the umbilical region.
Lumbar vertebrae
Lumb/o = loin, lower back, -ar = pertaining to
The largest, out of all the vertebrae, located between the thoracic vertebrae and the sacral vertebrae in the spinal column; labeled as L1 through L5.
Membrane-bound organelles that contain hydrolases, responsible for the digestion of macromolecules, old or damaged cells, and microbes.
A point on the right lower abdomen, about two-thirds the distance between the umbilicus and anterior superior iliac spine (ASIS). It is the point of maximum tenderness in patients with acute appendicitis.
A thin layer that forms the outer boundary of a cell, body cavity, organs, or internal passageways.
Membrane-bound organelles involved in energy (adenosine triphosphate aka ATP) production, cell signaling, and cell fate.
nucle/o = nucleus, core, inner part;
-us = noun suffix
A membrane-bound organelle that functions as the core of a eukaryotic cell.
A group of tissues that perform a specific function.
pelv/I = pelvis; -ic = relating to
A bowl-shaped lower front cavity of the body sits beneath the abdominal cavity; houses the urinary bladder and reproductive organs.
peritone/o = peritoneum; -us = noun suffix
A thin serous membrane consisting of a single layer of the mesothelium. The parietal peritoneum lines the abdominal wall, whereas the visceral peritoneum lines the abdominal viscera.
RNA-rich cell organelles that make proteins; often called protein factories of the cell.
sacr/o = sacrum, sacred bone, holy bone; -um = noun suffix
The sacrum is a single, inverted triangle-shaped bone, composed of five individual vertebrae that fuse during adulthood; forms the base of the spine and the pelvis.
skelet/o = skeleton, dried up; -al = pertaining to
Striated muscle tissue that is attached to bones by tendons; functions to contract and permit the movement of skeleton.
Smooth muscle
Involuntary muscles found in the walls of hollow organs, such as the intestines, uterus, and stomach.
spin/o = the spine, spinal cord, vertebral column; -al = relating to
The cavity within the vertebral column contains the spinal cord and the spinal nerve roots branching off the spinal cord. Also referred to as the spinal canal or vertebral canal.
thorac/o = chest, thorax, the breast, breastplate; -ic = relating to
The chest cavity, houses the tissues and organs of the respiratory system (lungs, bronchi, trachea, pleura), cardiovascular system (heart, pericardium, great vessels, lymphatics), nervous system (vagus nerve, sympathetic chain, phrenic nerve, recurrent laryngeal nerve), immune system (thymus), and digestive (esophagus) system.
Thoracic vertebrae
thorac/o = chest, thorax, the breast, breastplate; -ic = relating to
A stack of 12 vertebrae located between the cervical and lumbar vertebrae; labeled from T1 through T12. The thoracic vertebrae hold the rib cage and protect the delicate organs of the thorax, including the heart and lungs.
A group of structurally similar cells, in close proximity, organized to perform specific functions. For example, adipose tissue is a group of adipose cells.
umbilic/o = a middle point, center, navel; -al = pertaining to
One of the nine regions of the abdomen, located between the right and left lumbar regions and directly beneath the epigastric region. Contains the navel, also called the umbilicus.
Umbilicus
umbilic/o = a middle point, centre, navel; -us = noun suffix
The navel, or belly button; the remnant of what was once the umbilical cord in a newborn.
viscer/o = organs within a body cavity, internal organs;
-al = pertaining to
Of or related to viscera, or the internal organs within the body, specifically those within the thoracic cavity (the heart or the lungs), or abdominal cavity (the liver, the pancreas, or intestines).
Visceral muscle
viscer/o = organs within a body cavity, internal organs; -al = pertaining to
Smooth muscles of the viscera, especially those in the abdominal cavity.
Quick Introduction– provides an overview and introduction to medical terminology.
Medical Terms – rules governing singular versus plural versions of medical terms are described.
Word Building Reference– This resource strengthens your understanding of medical terminology. See how common medical terms are created using the various prefixes, suffixes, and root words.
Medical Terminology Intuitive Section
This section was developed for ‘speed learning’ of medical terminology.
