Sectioning in anatomy is crucial to observing structural and morphological features.
From whole organisms to tissues, parts are cut in different ways to look at details such as bone, muscle, parenchymal cells or skin in multiple angles, enabling a more complete understanding of how an organism lives or functions, or how it is sick or diseased.
How is a longitudinal section different from a transverse section?
The main difference between a longitudinal and transverse section is in how they are divided. Longitudinal sections are created when a plane cuts through the body at its longest axis, while transverse sections are made when a cut is made perpendicular to the longitudinal section.
What is a Longitudinal Section?
To accurately understand what a longitudinal section is, it is necessary to first review the concept of the longitudinal axis.
In anatomy, the longitudinal axis is an imaginary line going from the topmost to the bottommost part of an object. Such a line must also pass through the object’s center. Broadly speaking, the longitudinal axis would go from the head to toe of a human. Another general rule is that a longitudinal axis corresponds to the lengthwise cut of an object.
Two types of longitudinal sections exist: the sagittal and coronal section.
If an invisible cut would be made to divide an organism into left and right halves, the resulting halves would be sagittal sections.
A longitudinal section that evenly splits an object into equal left and right parts is called a median sagittal section or, simply, a median section.
Sagittal sections don’t need to result in equal halves. The cut can be made anywhere along an object’s longitudinal axis. The result is called a parasagittal section.
Coronal sections are cut perpendicular to the sagittal plane, resulting in the body being divided into front and back parts instead.
What is a Transverse Section?
A transverse section is created by a cut perpendicular to the longitudinal axis; to analogize, if a longitudinal cut divided a human being into left and right parts, a transverse cut would divide them into top and bottom parts.
An easy way to look at a transverse plane is that it is parallel with the ground. When such a cut is produced, the resulting transverse sections are divided into superior and inferior sections—or upper and lower parts.
In its simplest interpretation, a transverse section is created by cutting horizontally relative to an object’s position.
Differences Between Longitudinal and Transverse Sections
Both types of anatomical sections can be described by their relation to the longitudinal axis.
A longitudinal section divides an object along the longitudinal axis—roughly, from top to bottom, creating left and right parts which can be equal or not.
In contrast, transverse sections are divided perpendicularly to the longitudinal axis, yielding parts that can be classified as upper or lower.
Depending on where longitudinal sections are divided, they can be categorized as different types.
Sagittal sections split the object into left and right parts.
- Cutting along an object’s line of symmetry yields median sagittal sections, whose parts are equal to each other.
- Otherwise, cutting elsewhere along the longitudinal axis produces parasagittal section in which the sections are unequal.
Coronal sections split the object into front and back parts. In anatomy, “front and back” can also be referred to as “anterior and posterior” sections.
Transverse sections don’t have specific subtypes.
Longitudinal sections divide things into either left-right (sagittal) or anterior-posterior (coronal) pairs, while transverse sectioning produces upper-lower pairs.
“Upper or lower” transverse sections can also be called “cranial or caudal” or “superior or inferior” pairs.
Because the longitudinal axis runs along an object at its longest, and transverse sections are cut across such an axis, it is naturally easier to cut more transverse sections from a specimen than longitudinal sections.
The most relatable application of anatomical sectioning is to the human specimen.
The longitudinal axis passes through features such as the bridge of the nose, the navel, the spine, and the genitals—this is because humans exhibit bipedal symmetry.
In most anatomy diagrams, the transverse plane can be seen cutting across the waist, dividing the body into an upper part consisting of the head, torso, and arms; and a lower part made up by the hips and legs.
In practice, the transverse section can be cut anywhere across our longitudinal axis. For instance, chest transverse imaging can provide a top-view of the organs in a patient’s chest cavity.
For dogs, wolves, and other quadrupeds, anatomical sectioning is slightly different.
Due to their body plan, the longitudinal axis is changed to a horizontal orientation, following the neuraxis—or direction of the nervous system—of the quadruped.
As seen in the photo above, the sagittal sections still follow a cut along the animal’s length.
In quadrupeds, the coronal plane is more commonly referred to as the dorsal plane, dividing the body into the ventral (back) and dorsal (front) parts of the animal.
The same principles here can apply to elongated animals, such as snakes, annelids and various helminths.
Some organisms have no definite shape, and continually change—by extending pseudopods, as with amoeboid organisms.
In asymmetrical organisms such as amoebae or spherical ones like sea urchins, transverse and longitudinal sections are impractical due to the lack of distinction between the resulting divisions.
As with transverse planes, a transverse section may also be called a “transaxial” or “axial” section. The prefix “trans-“ indicates a cut across or perpendicular to the axis. Another simple term for a transverse section is “horizontal section.”
The different types of planes that create longitudinal sections also have alternative names; to wit:
- Sagittal plane: anteroposterior or lateral plane, as it cuts from the front to the back of the object, and separates the parts into a left-right pair.
- Coronal plane: frontal plane, as it separates the parts into a front-back pair.
Comparison Chart: Longitudinal Section vs Transverse Section
|Areas||Longitudinal Section||Transverse Section|
|Orientation||Cut along the longitudinal axis||Cut perpendicular to the longitudinal axis|
|Variations||Sagittal, parasagittal, median sagittal, coronal||None|
|Sectioning||Left-right (sagittal), anterior-posterior (coronal)||Superior-inferior|
|Quantity||Fewer sections can be cut from a specimen||Easier to cut more transverse sections from a specimen|
|In Humans||Divided from head to toe||Divided from side to side (laterally)|
|In Canines||Horizontal position. Coronal plane is known as “dorsal” plane.||Vertical position.|
|Alternative Names||Anteroposterior or lateral (sagittal), frontal (coronal)||Transaxial, horizontal|
How are Longitudinal and Transverse Sections Similar?
Longitudinal and transverse sections are essential analytical tools for studying anatomy. They provide a simple framework for organizing the locations of different body parts, tissues, and anatomical features in relation to one another.
Both sections are used in medical imaging to provide various views of an organ or body part; their applications include:
- Diagnostic ultrasound (sonography)
- Magnetic resonance imaging (MRI)
- Computed tomography (CT)
- Positron emission tomography (PET)
The two terms are commonly heard in the context of biology; students learning about botany, anatomy—or later on—histology will frequently encounter longitudinal and transverse sections.
What are the anatomical planes?
Four planes are employed in the study of anatomy: the coronal, sagittal, and transverse (axial) are all discussed in this article and are the three basic planes.
The fourth, the median plane, is a special subset of the sagittal plane which cuts at the line of symmetry along the longitudinal axis. This line is named because the halves produced would be roughly symmetrical to each other.
Another name for the median plane is the cardinal sagittal plane.
A fifth type, the oblique plane, describes a cut dividing a specimen at any other angle, combining a transverse and longitudinal section.
What are examples of a longitudinal section?
The simplest example of a longitudinal section can be seen in making a banana split, where the banana is cut in half lengthwise so that ice cream scoops can be placed between the two slices.
The human brain can be divided into its left and right hemisphere; an imaginary plane precisely between the hemispheres creates sagittal sections.
What are examples of a transverse section?
People commonly create transverse sections in their daily lives.
A transverse section is made in cutting slices of cucumber or sausage for a sandwich, or in snipping the top of an instant coffee stick. Slices of tomato, orange, lime, or pomegranate are typically transverse cuts.
A longitudinal section is different from a transverse section because it divides an object along its longitudinal axis, thereby creating left-right (sagittal) or anterior-posterior (coronal) pairs.
To contrast, a transverse section cuts the same specimen across its longitudinal axis, producing top and bottom (superior and inferior) pairs. For this reason, they are also known as transaxial sections.
Both provide different views to better study a specimen and its internal features, especially in histology and medical imaging.