2 Medical Language Related to the Body as a Whole

Learning Objectives

  • Use the anatomic reference system to identify the anatomic position of the body
  • Use the anatomic reference system to identify the body planes
  • Use the anatomic reference system to identify the body cavities
  • Use the anatomic reference system to identify the directional terms
  • Use the anatomic reference system to identify the divisions of the body
  • Describe the structural organization of the body
  • Apply the rules of medical language
  • Identify meanings of key word components

 

As you memorize the language components of medical terminology, it is important to support that learning within the context of anatomy and physiology. Proceeding through the body system chapters you will learn word parts, whole medical terms, and common abbreviations. It is important to put into context where in the body the medical term is referencing, and then consider how it works within the body.

Anatomy focuses on structure and physiology focuses on function. Much of the study of physiology centers on the body’s tendency toward homeostasis.

Consider the structures of the body in terms of fundamental levels of organization that increase in complexity: subatomic particles, atoms, molecules, organelles, cells, tissues, organs, organ systems, organisms, and biosphere (Figure 2.1).

The Levels of Organization

All matter in the universe is composed of one or more unique pure substances called elements, familiar examples are hydrogen, oxygen, carbon, nitrogen, calcium, and iron.

  • The smallest unit of any of these pure substances (elements) is an atom.
    • Atoms are made up of subatomic particles such as the proton, electron, and neutron.
  • Two or more atoms combine to form a molecule, such as the water molecules, proteins, and sugars found in living things.
    • Molecules are the chemical building blocks of all body structures.
  • A cell is the smallest independently functioning unit of a living organism.
    • Even bacteria, which are extremely small, independently-living organisms, have a cellular structure. Each bacterium is a single cell. All living structures of human anatomy contain cells, and almost all functions of human physiology are performed in cells or are initiated by cells
    • A human cell typically consists of flexible membranes that enclose cytoplasm, a water-based cellular fluid, together with a variety of tiny functioning units called organelles. In humans, as in all organisms, cells perform all functions of life.
  • A tissue is a group of many similar cells (though sometimes composed of a few related types) that work together to perform a specific function.
  • An organ is an anatomically distinct structure of the body composed of two or more tissue types. Each organ performs one or more specific physiological functions.

An organ system is a group of organs that work together to perform major functions or meet the physiological needs of the body.

Did you know?

  • Organs are very collaborative and work with multiple body systems.
  • For example, the heart (cardiovascular system) and lungs (respiratory system) work together to deliver oxygen throughout the body and remove carbon dioxide from the body.

 

Watch the video: Introduction to Anatomy & Physiology: Crash Course Anatomy & Physiology #1 (11 minutes)

 

Media 2.1. Introduction to Anatomy & Physiology: Crash Course A&P #1 [Online video]. Copyright 2015 by CrashCourse.

Did you know?

Terminology is used for the purpose of precision and reduction of medical error.

Anatomical Position

Health care providers use terminology for the purpose of precision and to reduce medical errors. For example, is a scar “above the wrist” located on the forearm two or three inches away from the hand? Or is it at the base of the hand? Is it on the palm-side or back-side? By using precise anatomical terminology, we eliminate ambiguity. Anatomical terms derive from ancient Greek and Latin words.

To further increase precision, anatomists standardize the way in which they view the body. Just as maps are normally oriented with north at the top, the standard body “map,” or anatomical position, is that of the body standing upright, with the feet at shoulder width and parallel, toes forward. The upper limbs are held out to each side, and the palms of the hands face forward as illustrated.

Using this standard position reduces confusion. It does not matter how the body being described is oriented, the terms are used as if it is in anatomical position. For example, a scar in the “anterior (front) carpal (wrist) region” would be present on the palm side of the wrist. The term “anterior” would be used even if the hand were palm down on a table.

This illustration shows an anterior and posterior view of the human body. The cranial region encompasses the upper part of the head while the facial region encompasses the lower half of the head beginning below the ears. The eyes are referred to as the ocular region. The cheeks are referred to as the buccal region. The ears are referred to as the auricle or otic region. The nose is referred to as the nasal region. The chin is referred to as the mental region. The neck is referred to as the cervical region. The trunk of the body contains, from superior to inferior, the thoracic region encompassing the chest, the mammary region encompassing each breast, the abdominal region encompassing the stomach area, the coxal region encompassing the belt line, and the pubic region encompassing the area above the genitals. The umbilicus, or naval, is located at the center of the abdomen. The pelvis and legs contain, from superior to inferior, the inguinal or groin region between the legs and the genitals, the pubic region surrounding the genitals, the femoral region encompassing the thighs, the patellar region encompassing the knee, the crural region encompassing the lower leg, the tarsal region encompassing the ankle, the pedal region encompassing the foot and the digital/phalangeal region encompassing the toes. The great toe is referred to as the hallux. The regions of the upper limbs, from superior to inferior, are the axillary region encompassing the armpit, the brachial region encompassing the upper arm, the antecubital region encompassing the front of the elbow, the antebrachial region encompassing the forearm, the carpal region encompassing the wrist, the palmar region encompassing the palm, and the digital/phalangeal region encompassing the fingers. The thumb is referred to as the pollux. The posterior view contains, from superior to inferior, the cervical region encompassing the neck, the dorsal region encompassing the upper back and the lumbar region encompassing the lower back. The regions of the back of the arms, from superior to inferior, include the cervical region encompassing the neck, acromial region encompassing the shoulder, the brachial region encompassing the upper arm, the olecranal region encompassing the back of the elbow, the antebrachial region encompasses the back of the arm, and the manual region encompassing the palm of the hand. The posterior regions of the legs, from superior to inferior, include the gluteal region encompassing the buttocks, the femoral region encompassing the thigh, the popliteus region encompassing the back of the knee, the sural region encompassing the back of the lower leg, and the plantar region encompassing the sole of the foot. Some regions are combined into larger regions. These include the trunk, which is a combination of the thoracic, mammary, abdominal, naval, and coxal regions. The cephalic region is a combination of all of the head regions. The upper limb region is a combination of all of the arm regions. The lower limb region is a combination of all of the leg regions.
Figure 2.4. Regions of the Human Body. The human body is shown in anatomical position in an (a) anterior view and a (b) posterior view. The regions of the body are labeled in boldface. Remixed image from Betts, et al., 2021. Licensed under CC BY 4.0

A body that is lying down is described as either prone or supine.  These terms are sometimes used in describing the position of the body during specific physical examinations or surgical procedures.

Directional Terms

Directional terms are essential for describing the relative locations of different body structures. For instance, an anatomist might describe one band of tissue as “inferior to” another or a physician might describe a tumor as “superficial to” a deeper body structure. Commit these terms to memory to avoid confusion when you are studying or describing the locations of particular body parts.

  • Anterior (or ventral) describes the front or direction toward the front of the body. The toes are anterior to the foot.
  • Posterior (or dorsal) describes the back or direction toward the back of the body. The popliteus is posterior to the patella.
  • Superior (or cranial) describes a position above or higher than another part of the body proper. The orbits are superior to the oris.
  • Inferior (or caudal) describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column). The pelvis is inferior to the abdomen.
  • Lateral describes the side or direction toward the side of the body. The thumb (pollex) is lateral to the digits.
  • Medial describes the middle or direction toward the middle of the body. The hallux is the medial toe.
  • Proximal describes a position in a limb that is nearer to the point of attachment or the trunk of the body. The brachium is proximal to the antebrachium.
  • Distal describes a position in a limb that is farther from the point of attachment or the trunk of the body. The crus is distal to the femur.
  • Superficial describes a position closer to the surface of the body. The skin is superficial to the bones.
  • Deep describes a position farther from the surface of the body. The brain is deep to the skull.
This illustration shows two diagrams: one of a side view of a female and the other of an anterior view of a female. Each diagram shows directional terms using double-sided arrows. The cranial-distal arrow runs vertically behind the torso and lower abdomen. The cranial arrow is pointing toward the head while the caudal arrow is pointing toward the tail bone. The posterior/anterior arrow is running horizontally through the back and chest. The posterior or dorsal arrow is pointing toward the back while the anterior, or ventral arrow, is pointing toward the abdomen. On the anterior view, the proximal/distal arrow is on the right arm. The proximal arrow is pointing up toward the shoulder while the distal arrow is pointing down toward the hand. The lateral-medial arrow is a horizontal arrow on the abdomen. The medial arrow is pointing toward the navel while the lateral arrow is pointing away from the body to the right. Right refers to the right side of the woman’s body from her perspective while left refers to the left side of the woman’s body from her perspective.
Figure 2.5. Directional Terms Applied to the Human Body. Paired directional terms are shown as applied to the human body. From Betts, et al., 2021. Licensed under CC BY 4.0.

Practice these directional terms.

 

Concept Check

  • Find a partner and take turns choosing two body parts on your or your partner’s body.
  • Using directional terms, describe the location of those body parts relative to one another.

Body Planes

A section is a two-dimensional surface of a three-dimensional structure that has been cut. Modern medical imaging devices enable clinicians to obtain “virtual sections” of living bodies. We call these scans. Body sections and scans can be correctly interpreted, however, only if the viewer understands the plane along which the section was made. A plane is an imaginary two-dimensional surface that passes through the body. There are three planes commonly referred to in anatomy and medicine:

  • The sagittal plane is the plane that divides the body or an organ vertically into right and left sides. If this vertical plane runs directly down the middle of the body, it is called the midsagittal or median plane. If it divides the body into unequal right and left sides, it is called a parasagittal plane or less commonly a longitudinal section.
  • The frontal plane is the plane that divides the body or an organ into an anterior (front) portion and a posterior (rear) portion. The frontal plane is often referred to as a coronal plane. (“Corona” is Latin for “crown.”)
  • The transverse plane is the plane that divides the body or organ horizontally into upper and lower portions. Transverse planes produce images referred to as cross sections.

Exercise: Can you locate …?

Body Cavities and Serous Membranes

The body maintains its internal organization by means of membranes, sheaths, and other structures that separate compartments. The dorsal (posterior) cavity and the ventral (anterior) cavity are the largest body compartments (Figure 2.6). These cavities contain and protect delicate internal organs, and the ventral cavity allows for significant changes in the size and shape of the organs as they perform their functions. The lungs, heart, stomach, and intestines, for example, can expand and contract without distorting other tissues or disrupting the activity of nearby organs.

This illustration shows a lateral and anterior view of the body and highlights the body cavities with different colors. The cranial cavity is a large, bean-shaped cavity filling most of the upper skull where the brain is located. The vertebral cavity is a very narrow, thread-like cavity running from the cranial cavity down the entire length of the spinal cord. Together the cranial cavity and vertebral cavity can be referred to as the dorsal body cavity. The thoracic cavity consists of three cavities that fill the interior area of the chest. The two pleural cavities are situated on both sides of the body, anterior to the spine and lateral to the breastbone. The superior mediastinum is a wedge-shaped cavity located between the superior regions of the two thoracic cavities. The pericardial cavity within the mediastinum is located at the center of the chest below the superior mediastinum. The pericardial cavity roughly outlines the shape of the heart. The diaphragm divides the thoracic and the abdominal cavities. The abdominal cavity occupies the entire lower half of the trunk, anterior to the spine. Just under the abdominal cavity, anterior to the buttocks, is the pelvic cavity. The pelvic cavity is funnel shaped and is located inferior and anterior to the abdominal cavity. Together the abdominal and pelvic cavity can be referred to as the abdominopelvic cavity while the thoracic, abdominal, and pelvic cavities together can be referred to as the ventral body cavity.
Figure 2.6. Dorsal and Ventral Body Cavities. The ventral cavity includes the thoracic and abdominopelvic cavities and their subdivisions. The dorsal cavity includes the cranial and spinal cavities. From Betts, et al., 2021. Licensed under CC BY 4.0.

Subdivisions of the Posterior (Dorsal) and Anterior (Ventral) Cavities

The posterior (dorsal) and anterior (ventral) cavities are each subdivided into smaller cavities:

The posterior (dorsal) cavity has two main subdivisions:

  • In the posterior (dorsal) cavity, the cranial cavity houses the brain
  • The spinal cavity (or vertebral cavity) encloses the spinal cord.

The anterior (ventral) cavity has two main subdivisions:

  • The thoracic cavity is the more superior subdivision of the anterior cavity, and it is enclosed by the rib cage.
    • The thoracic cavity contains the lungs and the heart, which is located in the mediastinum.
    • The diaphragm forms the floor of the thoracic cavity and separates it from the more inferior abdominopelvic cavity.
  • The abdominopelvic cavity is the largest cavity in the body.
    • No membrane physically divides the abdominopelvic cavity.
    • The abdominal cavity houses the digestive organs, the pelvic cavity, and the reproductive organs.

Exercise: Practice locating cavities.

Abdominal Regions and Quadrants

To promote clear communication, for instance about the location of a patient’s abdominal pain or a suspicious mass, health care providers typically divide up the cavity into either nine regions or four quadrants.

Exercise: Practice locating the quadrants.

Tissue Membranes

A tissue membrane is a thin layer or sheet of cells that covers the outside of the body (for example, skin), the organs (for example, pericardium), internal passageways that lead to the exterior of the body (for example, abdominal mesenteries), and the lining of the movable joint cavities. There are two basic types of tissue membranes: connective tissue and epithelial membranes (Figure 2.7).

This illustrations shows the silhouette of a human female from an anterior view. Several organs are showing in her neck, thorax, abdomen left arm and right leg. Text boxes point out and describe the mucous membranes in several different organs. The topmost box points to the mouth and trachea. It states that mucous membranes line the digestive, respiratory, urinary and reproductive tracts. They are coated with the secretions of mucous glands. The second box points to the outside edge of the lungs as well as the large intestine and states that serous membranes line body cavities that are closed to the exterior of the body, including the peritoneal, pleural and pericardial cavities. The third box points to the skin of the hand. It states that cutaneous membrane, also known as the skin, covers the body surface. The fourth box points to the right knee. It states that synovial membranes line joint cavities and produce the fluid within the joint.
Figure 2.7. Tissue Membranes. The two broad categories of tissue membranes in the body are (1) connective tissue membranes, which include synovial membranes, and (2) epithelial membranes, which include mucous membranes, serous membranes, and the cutaneous membrane, in other words, the skin. From Betts, et al., 2021. Licensed under CC BY 4.0.

Did you know?

Synovial membranes line cavities which hold synovial fluid.

Synovial fluid lubricates the joints for movement.

 

Connective Tissue Membranes

  • The connective tissue membrane is formed solely from connective tissue.
    • These membranes encapsulate organs, such as the kidneys, and line our movable joints.
  • A synovial membrane is a type of connective tissue membrane that lines the cavity of a freely movable joint.
    • For example, synovial membranes surround the joints of the shoulder, elbow, and knee.

Epithelial Membranes

  • The epithelial membrane is composed of epithelium attached to a layer of connective tissue.
    • For example, your skin.
  • The mucous membrane is also a composite of connective and epithelial tissues.
    • Sometimes called mucosa, these epithelial membranes line the body cavities and hollow passageways that open to the external environment, and include the digestive, respiratory, excretory, and reproductive tracts.
    • Mucus, produced by the epithelial exocrine glands, covers the epithelial layer.
    • The underlying connective tissue, called the lamina propria (literally “own layer”), help support the fragile epithelial layer.
  • The skin is an epithelial membrane also called the cutaneous membrane.
    • It is a stratified squamous epithelial membrane resting on top of connective tissue. The apical surface of this membrane is exposed to the external environment and is covered with dead, keratinized cells that help protect the body from desiccation and pathogens.

Membranes of the Anterior (Ventral) Body Cavity

  • A serous membrane (also referred to as serosa) is an epithelial membrane composed of mesodermally derived epithelium called the mesothelium that is supported by connective tissue.
    • Parietal layers: line the walls of the body cavity.
    • Visceral layer:  covers the organs (the viscera).
    • Between the parietal and visceral layers is a very thin, fluid-filled serous space.
This diagram shows the pericardium on the left next to an analogy of a hand punching a balloon on the right. The pericardium is a two-layered sac that surrounds the entire heart except where the blood vessels emerge on the heart’s superior side. The pericardium has two layers because it folds over itself in the shape of the letter U. The inner layer that borders the heart is the visceral pericardium while the outer layer is the parietal pericardium. The space between the two layers is called the pericardial cavity. The heart sits in the cavity much like a fist punching into a balloon. The balloon surrounds the lower part of the fist with a two-layered sac, with the top of the balloon, where it contacts the fist, being analogous to the visceral pericardium. The bottom of the balloon, where it is tied off, is analogous to the parietal pericardium. The air within the balloon is analogous to the pericardial cavity.
Figure 2.8. Serous Membrane. Serous membrane lines the pericardial cavity and reflects back to cover the heart—much the same way that an underinflated balloon would form two layers surrounding a fist. From Betts, et al., 2021. Licensed under CC BY 4.0.

There are three serous cavities and their associated membranes. Serous membranes provide additional protection to the viscera they enclose by reducing friction that could lead to inflammation of the organs.

  • Pleura: surrounds the lungs in the pleural cavity and reduces friction between the lungs and the body wall.
  • Pericardium:  surrounds the heart in the pericardial cavity and reduces friction between the heart and the wall of the pericardium.
  • Peritoneum: surrounds several organs in the abdominopelvic cavity. The peritoneal cavity reduces friction between the abdominal and pelvic organs and the body wall.

Test Yourself

Use these practice activities to review the concepts in this chapter. If you prefer, there is a printable version of these activities.

Test your knowledge of terms related to the body as a whole by answering the questions below.

 

Use the anatomic reference system to identify the body planes below.

 

Use the anatomic reference system to identify the body cavities.

 

Practice pronouncing and defining the following directional terms.

 

Use the anatomic reference system to identify the regions and quadrants of the body pictured below.

Chapter Attributions

This chapter was adapted by Jerry Casteel from “Medical Language Related to the Body as a Whole” by Stacey Grimm; Coleen Allee; Elaine Strachota; Laurie Zielinski; Traci Gotz; Micheal Randolph; and Heidi Belitz. Licensed under a CC BY 4.0 license.

Media Attributions

Introduction to Anatomy & Physiology: Crash Course Anatomy & Physiology #1 by CrashCourse is licensed under the Standard YouTube license.

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Medical Terminology Copyright © 2024 by Phoenix College Nursing is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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