FIRST, FIND YOUR VIEW
A plane is the direction of the slice through the body.
MRI creates a stack of thin sections. Each section shows the body from a particular direction. The three primary anatomical planes are axial, sagittal, and coronal. MRI can also angle a stack into an oblique plane so it follows the anatomy more closely.
Think of looking across the body in horizontal sections. It is also called the transverse plane.
A midsagittal slice passes through the midline. Parasagittal slices sit to either side of it.
Think of a section that separates the front of the body from the back.
The stack is tilted away from the exact primary planes to match a joint, vessel, nerve, organ, or other structure.
ORIENT THE DISPLAY
The patient's right may appear on your left.
Axial images are commonly displayed as if you are standing at the patient's feet and looking toward the head. In that view, the patient's right side appears on the left side of the screen. Coronal images are commonly viewed as if you are facing the patient, so the patient's right again appears on your left.
Sagittal images show the patient from the side. Anterior and posterior placement depends on the display convention. Never rely only on habit. Read the orientation labels and localizer, especially when the images are reformatted, flipped, rotated, or acquired with the patient in an unusual position.
Use the R, L, A, P, H, and F markers.
R and L identify the patient's right and left. A and P mark anterior and posterior. H and F point toward the head and feet. Some systems use S and I for superior and inferior. Check the labels before deciding which side or direction you are seeing.
SPEAK THE LANGUAGE OF LOCATION
Direction terms describe one structure in relation to another.
The sternum is anterior to the heart. The spine is posterior to the heart.
The head is superior to the chest. The pelvis is inferior to the abdomen.
The nose is medial to the eyes. The shoulders are lateral to the neck.
The elbow is proximal to the wrist. The fingers are distal to the elbow.
Subcutaneous fat is superficial to muscle. Bone may be deep to the surrounding muscle.
The right arm and right leg are ipsilateral. The right arm and left leg are contralateral.
Supine means lying face up. Prone means lying face down. Decubitus means lying on a side. These terms describe how the patient is positioned, not the plane of the acquired image. A supine patient can still have axial, sagittal, coronal, and oblique images.
USE THE P.L.A.N.E. METHOD
Do not begin by guessing the structure.
Decide whether the image is axial, sagittal, coronal, or oblique.
Confirm right, left, anterior, posterior, head, and feet from the displayed markers.
Find a structure you recognize, such as the midline, vertebral body, joint surface, organ border, or major vessel.
Use relationships such as medial, lateral, anterior, posterior, superior, and inferior to locate nearby structures.
Scroll through neighboring slices. A structure's shape changes as the plane moves through it.
Remember: One slice is a clue. The full stack tells the anatomical story.
CHECK YOUR ORIENTATION
Choose the correct anatomical idea.
An image divides the body into right and left portions. Which plane is it?
It is sagittal. If the slice passes directly through the midline, it is midsagittal. A slice beside the midline is parasagittal.
On a conventionally displayed axial image, anatomy on the left side of the screen is usually which side of the patient?
It is usually the patient's right side because the image is commonly viewed from the feet. Always confirm with the orientation markers because displays and reformats can vary.
The wrist is farther from the shoulder than the elbow. Which direction term describes the wrist relative to the elbow?
The wrist is distal to the elbow. The elbow is proximal to the wrist.
A knee sequence is angled to follow the anterior cruciate ligament. Is it still a primary plane?
It is an oblique plane. It may be described as oblique sagittal, oblique coronal, or another angled orientation based on how the stack was planned.
Why should you scroll through neighboring slices before naming a structure?
A three dimensional structure changes shape from slice to slice. Following it through the stack helps confirm its course, connections, and identity.
LESSON 46 COMPLETE
You can identify the imaging plane, read orientation labels, use direction terms, and find anatomy from reliable landmarks.Educational references
This lesson supports education and does not replace the orientation markers, approved protocol, image display standards, or qualified clinical interpretation used by a facility. Always verify patient side and direction from the image labels and full study.