What is the anatomical position of a CT scan? An expert guide

September 29, 2025 •

4 min read

Standardized positioning is fundamental to medical imaging, which is why understanding what is the anatomical position of a CT scan? is crucial for interpreting results.

While a CT scan doesn't require a patient to be in the upright anatomical stance, the principles of this universal medical reference guide the entire imaging process.

Quick Summary

The anatomical position is a universal reference point (standing, palms forward) used to standardize medical language. For a CT scan, this reference is used to interpret images, while the patient is typically lying down in a position like supine or prone. The scan's orientation is always documented relative to this standard, ensuring consistent interpretation regardless of the patient's actual physical position during the procedure.

Key Points

Reference Frame, Not Position: The anatomical position (standing erect, palms forward) is a universal reference for interpretation, not the patient's actual stance during a CT scan.
Supine is Common: Patients are most often positioned supine (on their back) for a CT scan, especially for the head, chest, and abdomen.
Positions Vary by Scan: The exact patient position, such as prone (on the stomach) or with arms raised, changes depending on the body part being scanned.
Planes for Interpretation: CT images are viewed in axial, coronal, and sagittal planes, which are all defined relative to the standard anatomical position.
Immobilization is Key: Patient immobilization with straps and pillows is essential for reducing motion artifacts and ensuring high-quality, diagnostically accurate images.
Radiation Safety: Proper positioning helps minimize unnecessary radiation dose by keeping the target area centered and the scan efficient.

Demystifying the anatomical position in radiology

The anatomical position is a universal standard in medical science, defined as a person standing erect, with arms at their sides, palms facing forward, and feet together. It serves as a fixed reference point, allowing medical professionals to describe the location and relationship of body structures precisely and consistently, preventing confusion, which is critical in all fields, including diagnostic radiology.

For a CT scan, a patient is never actually positioned in this standing anatomical position. Instead, the images generated by the scanner are oriented and analyzed based on this standard reference frame. This means that a radiologist can look at a CT image and instantly understand what is anterior (front), posterior (back), superior (top), and inferior (bottom) relative to the body's standard orientation, regardless of how the patient was lying on the examination table.

Common patient positions during a CT scan

During a CT scan, the technologist will place the patient in a specific position on the scanner table, using pillows, straps, and foam wedges for support and to ensure the patient remains perfectly still. The most common positions are:

Supine: The patient lies on their back, facing upward. This is the most common position for scans of the head, chest, abdomen, and pelvis.
Prone: The patient lies on their stomach, facing downward. This position may be used for spinal examinations to reduce artifacts or for procedures like spinal injections.
Lateral: The patient lies on their side. This is a less common position for CT but can be used for specific circumstances where a lateral view is needed.

Why patient position varies

The specific position chosen for a CT scan depends on several factors, including the body part being scanned, the type of examination (e.g., with or without contrast), and the clinical question the radiologist is trying to answer. For a CT of the abdomen and pelvis, for example, the patient's arms are typically raised above their head. This is done to move the arms out of the imaging field, preventing streak artifacts caused by dense bone and metal from obscuring critical areas.

Imaging planes used in computed tomography

Once the patient is positioned, the CT scanner captures a series of cross-sectional images, or 'slices', of the body. These slices can be digitally reconstructed by a computer into different anatomical planes to provide a comprehensive view of the body's internal structures. The three primary planes are:

Axial (or Transverse) Plane: This plane divides the body horizontally into superior (upper) and inferior (lower) parts. A standard CT scan is composed of axial slices, often viewed as if looking up from the patient's feet.
Coronal Plane: This is a vertical plane that divides the body into anterior (front) and posterior (back) parts. CT software can reconstruct axial slices into a coronal view, which is particularly useful for visualizing structures like the spine or lungs.
Sagittal Plane: This is another vertical plane that divides the body into right and left sides. A sagittal reconstruction from CT data is excellent for visualizing the spine and its relationship to surrounding structures.

Comparison of CT positioning for different body parts


Body Part	Common Patient Position	Key Positioning Details
Head	Supine	Head is placed in a head holder, often with a pillow for comfort.
Chest/Abdomen	Supine	Patient's arms are raised above the head to minimize imaging artifacts.
Spine	Supine or Prone	Position depends on the specific region and clinical need. Prone can be used for certain spinal procedures.
Shoulder	Supine	The patient is positioned with the affected shoulder in the center of the scanner.

Ensuring accuracy with precise positioning

Accurate and consistent patient positioning is a critical component of producing high-quality diagnostic CT images. Movement during a scan, even slight, can cause motion artifacts that blur the images and make them difficult to interpret. This can lead to misdiagnosis or require a repeat scan, unnecessarily increasing the patient's radiation exposure.

Technologists use several techniques to ensure immobilization, including the use of restraining straps, head and limb holders, and clear communication with the patient about the importance of remaining still. They also use reference laser lines to mark the patient's position and ensure they are centered correctly within the scanner's gantry, guaranteeing the best possible image quality.

In conclusion, while the term what is the anatomical position of a CT scan? may seem to suggest a patient standing upright inside the scanner, the reality is that the anatomical position is a universal reference system. The patient is instead placed in a comfortable and stable position, usually supine or prone, and the resulting cross-sectional images are consistently interpreted using the framework provided by the standard anatomical position. Understanding this fundamental concept helps clarify why patient positioning is such a crucial step in the CT imaging process, ensuring accurate and reliable diagnostic outcomes.

For more detailed information on specific CT procedures and patient preparation, you can consult resources like the Radiological Society of North America's patient information pages: RadiologyInfo.org.

Frequently Asked Questions

Supine means lying on your back, face up. Prone means lying on your stomach, face down. The position used depends on the specific part of the body being examined and what will provide the clearest images.

Raising your arms moves them out of the scanner's field of view. This prevents dense bone and metal from creating image artifacts that could obscure important details in your chest or abdomen, improving image quality.

No, it is critical to remain as still as possible during the scan. Even minor movements can blur the images. Your technologist will give you clear instructions, and support devices will help you stay still.

The three main planes are axial (divides top and bottom), coronal (divides front and back), and sagittal (divides right and left). These planes allow radiologists to view and interpret the scanned anatomy from different perspectives.

The standard anatomical position is a universal constant. While the patient's actual position on the table changes for different body parts, all images are still interpreted relative to the fixed standard anatomical reference.

CT technologists are highly trained professionals who follow specific protocols for each type of scan. They use laser lines and other equipment to precisely position the patient relative to the scanner's center and the area of interest.

Yes, the standard anatomical position is a fundamental concept used across all medical fields, including X-rays, MRI, and ultrasound, to ensure a consistent and shared understanding of human anatomy.