Appendix A. Anatomical Terminology
There are several sets of anatomical terminology used within this book that may apply to the whole body. These terms are incredibly useful when understanding the structure, position, and direction of organs and organ systems. The below tables provide you with a selection of general terminology to reference. Familiarizing yourself with these terms will help you differentiate parts of the human body as you read.
Table A1
Throughout this text, you will encounter directional terms referring to the relative locations of different body parts. Table A1 provides a list of these terms, potential naming alternatives, and a brief definition of each term.
| Term | Alternative Term | Definition |
|---|---|---|
| Anterior | Ventral | front or direction toward the front of the body |
| Posterior | Dorsal | back or direction toward the back of the body |
| Superior | Cranial | a position above or higher than another part of the body proper |
| Inferior | Caudal | describes a position below or lower than another part of the body proper |
| Lateral | — | the side or direction toward the side of the body |
| Medial | — | the middle or direction toward the middle of the body |
| Proximal | — | position in a limb that is nearer to the point of attachment or the trunk of the body |
| Distal | — | position in a limb that is farther from the point of attachment or the trunk of the body |
| Superficial | — | position closer to the surface of the body |
| Deep | — | position farther from the surface of the body |
Table A2
In anatomy, physiology, and medicine, it is useful to think of the body along planes, or imaginary two-dimensional surfaces that pass through the body. These planes are most often used in medical imaging, allowing practitioners to interpret scans made by medical imaging equipment. Table A2 provides a list of the three most commonly used planes of the body.
| Plane | Alternative Term | Definition |
|---|---|---|
| Sagittal | — | divides the body or an organ vertically into right and left sides |
| Frontal | Coronal | divides the body or an organ into an anterior (front) portion and a posterior (rear) portion |
| Transverse | Horizontal | divides the body or organ horizontally into upper and lower portions |
In addition to generalized anatomical terminology, there is also specific terminology that applies to singular systems, such as the skeleton. Although these terms aren’t as encompassing as the terms found in Appendix A, they are still incredibly useful in understanding the different organ systems found throughout the book. The following tables may act as a reference for terms used to classify bones, joints, and muscles.
Table A3
Several chapters throughout this text explore the different bones of the human skeleton. It’s important to note that these bones are divided up into five different groupings based around their shape. Table A3 provides a list of names and definitions for these different groups as understanding these terms will help you to identify the different kinds of bones in the human body.
| Type | Definition |
|---|---|
| Long | cylinder-shaped bone that is longer than it is wide; functions as a lever |
| Short | cube-shaped bone that is approximately equal in length, width, and thickness; provides limited motion |
| Flat | thin and curved bone; serves as a point of attachment for muscles and protects internal organs |
| Irregular | bone of complex shape; protects internal organs from compressive forces |
| Sesamoid | small, round bone embedded in a tendon; protects the tendon from compressive forces |
Table A4
Throughout this text, we also explore the many different types of joints within the body. There are several different ways to classify joints, such as functional categories versus structural categories. Table A4 provides a list of terms used to classify joints that will help you in differentiating joints throughout the book.
| Type | Definition |
|---|---|
| Fibrous | joint where the articulating areas of the adjacent bones are connected by fibrous connective tissue |
| Cartilaginous | joint at which the bones are united by hyaline cartilage (synchondrosis) or fibrocartilage (symphysis) |
| Synovial | joint at which the articulating surfaces of the bones are located within a joint cavity formed by an articular capsule |
| Synarthrosis | immobile or nearly immobile joint |
| Amphiarthrosis | slightly mobile joint |
| Diarthrosis | freely mobile joint |
| Uniaxial | type of diarthrosis; joint that allows for motion within only one plane (one axis) |
| Biaxial | type of diarthrosis; a joint that allows for movements within two planes (two axes) |
| Multiaxial | type of diarthrosis; a joint that allows for movements within three planes (three axes) |
Table A5
While reading this text, you’ll also explore the various parts of the muscular system. Muscle fibers are often bundled up into a unit called a muscle fascicle, and furthermore we can classify these fascicles into different arrangements. Table A5 provides a list and definition of the most common fascicles seen in the human body. Reviewing this table will help you better identify and understand parts of the muscular system.
| Type | Definition |
|---|---|
| Parallel | fascicles that extend in the same direction as the long axis of the muscle |
| Parallel Fusiform | muscle that has fascicles that are spindle-shaped to create large bellies |
| Circular | (also, sphincter) fascicles that are concentrically arranged around an opening |
| Convergent | fascicles that extend over a broad area and converge on a common attachment site |
| Pennate | fascicles that are arranged differently based on their angles to the tendon |
| Unipennate | pennate muscle that has fascicles located on one side of the tendon |
| Bipennate | pennate muscle that has fascicles that are located on both sides of the tendon |
| Multipennate | pennate muscle that has a tendon branching within it |
