Anatomical Planes and Directional Terms

2. The Coronal (Frontal) Plane

The coronal plane (also known as the frontal plane) is a vertical cut made at right angles to the sagittal plane. This plane divides the body into anterior (front) and posterior (back) portions.

Etymology Note: The term coronal is derived from the "coronal suture," a joint in the skull that runs perpendicular to the sagittal suture.

3. The Transverse (Cross Section) Plane

The transverse plane, often referred to as a cross section, is a horizontal cut. Unlike the vertical sagittal and coronal planes, the transverse plane divides the body into upper and lower portions.

Directional Terms and Spatial Orientation

Once the body is divided into planes, we need a way to describe where one structure is located in relation to another. Anatomists use specific directional terms to ensure accuracy.

Medial vs. Lateral

These terms describe how close a structure is to the center of the body:

• Medial: Toward the midline or the median plane of the body.
• Lateral: Away from the midline, or toward the side of the body.

Proximal vs. Distal

These terms are most commonly used when describing the limbs (arms and legs) in relation to the trunk:

• Proximal: Toward the point of attachment to the body or toward the trunk.
• Distal: Away from the point of attachment or origin, or farthest from the trunk.

Superficial vs. Deep

These terms describe the depth of a structure or an injury:

• Superficial: Affecting the outer layers, such as the skin.
• Deep: Involving internal structures, such as internal organs.

Exam Tip: When a question asks about the "depth" of an injury, remember that a superficial injury is on the surface, while a deep injury penetrates toward the internal organs.

Describing Cavities and Organs

The terms external and internal have specific applications in anatomical descriptions. While "superficial" and "deep" describe the depth of an injury, the terms external and internal are specifically utilized when referring to the location of body cavities and hollow organs.

For example, if a medical report mentions an injury to an "internal" structure, it is likely referring to something located within a body cavity or inside a hollow organ, such as the stomach.

By mastering these planes and directional terms, students and medical professionals can accurately communicate the exact location, orientation, and extent of anatomical structures and medical conditions.