🔲 Medical Terminology Lesson

SAF: the three body planes

Every CT scan, MRI, and anatomical illustration you will ever read is sliced along one of three planes. SAF gives you all three and what each one separates.

Sagittal

Axial

Frontal

📖 Full Breakdown

The three planes that every medical image is built from

Radiology, surgery, and anatomy lab all describe structures relative to these three cutting planes — knowing them lets you orient any image instantly.

Sagittal

Divides the body into left and right portions. A midsagittal (or median) cut runs exactly down the midline, creating equal left and right halves; any other sagittal cut is called parasagittal.

Axial (Transverse)

Divides the body into upper (superior) and lower (inferior) portions. This is the plane used for standard CT scan slices — each slice is an axial cross-section.

Frontal (Coronal)

Divides the body into front (anterior) and back (posterior) portions. Also called the coronal plane, named for its similarity to a crown-line cut through the head.

🩺 Clinical / Exam Application

A radiologist reviewing a head CT says the tumor is visible "on axial slice 14, just anterior to the midsagittal line." That single sentence uses two planes at once: axial tells you which horizontal slice, and midsagittal tells you the left-right position relative to the true center. Being able to picture both planes simultaneously is what lets you translate radiology language into a 3D mental image.

⚠️ Exam Alert

Exam writers often ask you to identify which plane is shown in an image without labeling it. The test: if the image shows left AND right sides in one slice, it's sagittal or frontal; if it shows a horizontal "slice" with no left/right split, it's axial.

🚧 Common Trap

Students frequently swap "frontal" and "sagittal" because both sound related to front-facing views. Remember: frontal/coronal splits front from back (like a crown), while sagittal splits left from right (like an arrow, "sagitta" in Latin).

✅ Quick Check

You are shown an MRI slice that shows both the left ear and right ear in the same image, with the top of the head at the top of the image. Which plane is this?

📝 Exam Prep

Common Exam Questions

❓ What is the difference between the sagittal, axial, and frontal planes?

✅ Sagittal divides left from right, axial (transverse) divides top from bottom, and frontal (coronal) divides front from back. Every CT and MRI slice is described using one of these three planes.

❓ What is the difference between a midsagittal and a parasagittal cut?

✅ A midsagittal cut runs exactly along the body's midline, producing two equal left and right halves. A parasagittal cut is any sagittal-direction cut that is off-center, producing unequal portions.