Radiological Anatomy: Central Sulcus

OVERVIEW

This page is dedicated to covering how the central sulcus will appear across different radiological studies. It is an important anatomical structure in the brain.

The central sulcus is an important anatomical structure that can help with orientation when interpreting cranial anatomy (image source)
FINDING THE CENTRAL SULCUS ON AXIAL CROSS SECTIONS: OVERVIEW OF SIGNS

Given the importance of the central sulcus in orienting oneself to cranial anatomy, it is worth reviewing how one can quickly identify it. The following radiological signs are useful for finding the central sulcus on axial cross sections. The diagram below summarizes and depicts these different signs.

There are multiple different signs that can be used to locate the central sulcus on axial cross sections. Often times identifying structures around the central sulcus is also useful in contextualizing its anatomical location. These signs are discussed more in depth below.

The sections below further discuss the signs that are useful to identifying the central sulcus on axial imaging of the brain.

FINDING THE CENTRAL SULCUS ON AXIAL CROSS SECTIONS: SUPERIOR FRONTAL SULCUS SIGN (PRE-CENTRAL SULCUS SIGN)

Often times the posterior end of the frontal sulcus will connect to the pre-central sulcus. With this in mind, the central sulcus will reside more posterior to this sign.

The above images are from axial cross sections of a non-contrast head CT scan. They are both the same image, however the right pane is annotated to highlight important anatomy. The above image shows how the superior frontal sulcus (yellow line) connects to the pre-central sulcus (blue line). The central sulcus can be found posterior to them both (red line).

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A NON-CONTRAST HEAD CT-SCAN. CLICK THE THUMBNAILS TO VIEW THEM.

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A T1 WEIGHTED HEAD MRI WITHOUT CONTRAST. CLICK THE THUMBNAILS TO VIEW THEM.

FINDING THE CENTRAL SULCUS ON AXIAL CROSS SECTIONS: SIGMOID HOOK SIGN

This “hook” refers to the shape of the sulcus that follows the posterior surface of the pre-central gyrus. This hook can be seen well most of the time on CT scans and is seen almost always on MRI. The area of the “hook” corresponds to the motor area of the pre-central gyrus that controls the hand.

The images above are axial sections of a T1 weighted head MRI without contrast. Both images are the the same, however the right pane has been annotated to highlight important anatomy. The sigmoid hook signs are traced with red lines. This feature is characteristic of the central sulcus and marks its location.

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A NON-CONTRAST HEAD CT-SCAN. CLICK THE THUMBNAILS TO VIEW THEM.

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A T1 WEIGHTED HEAD MRI WITHOUT CONTRAST. CLICK THE THUMBNAILS TO VIEW THEM.

FINDING THE CENTRAL SULCUS ON AXIAL CROSS SECTIONS: PARS BRACKET SIGN

There are paired pars marginalia that form a “bracket” on either each side of the inter hemispheric fissure. These are at or posterior to the location of the central sulcus. 

The above images are from axial cross sections of a non-contrast head CT scan. They are both the same image, however the right pane is annotated to highlight important anatomy. The pars bracket sign (outlined with blue lines) is typically found to be next to, or posterior to, to the central sulcus (outlined with red lines).

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A NON-CONTRAST HEAD CT-SCAN. CLICK THE THUMBNAILS TO VIEW THEM.

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A T1 WEIGHTED HEAD MRI WITHOUT CONTRAST. CLICK THE THUMBNAILS TO VIEW THEM.

FINDING THE CENTRAL SULCUS ON AXIAL CROSS SECTIONS: BIFID POST-CENTRAL SULCUS SIGN

The post-central sulcus is often bifid in nature, and is located posterior to the central sulcus.

The above images are from axial cross sections of a non-contrast head CT scan. They are both the same image, however the right pane is annotated to highlight important anatomy. The bifid post-central sulcus is shown (outlined with blue lines) which will be posterior to the central sulcus (outlined with red lines).

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A NON-CONTRAST HEAD CT-SCAN. CLICK THE THUMBNAILS TO VIEW THEM.

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A T1 WEIGHTED HEAD MRI WITHOUT CONTRAST. CLICK THE THUMBNAILS TO VIEW THEM.

FINDING THE CENTRAL SULCUS ON AXIAL CROSS SECTIONS: THIN POST-CENTRAL GYRUS SIGN

The post-central gyrus is typically thinner then the pre-central gyrus. This can help localize the central sulcus which sits in between these gyri.

The images above are axial sections of a T1 weighted head MRI without contrast. Both images are the the same, however the right pane has been annotated to highlight important anatomy. The width of the pre-central gyrus (dashed blue line) is clearly thicker then that of the post-central gyrus (dashed yellow line). This thin post-central gyrus can help locate the central sulcus (red line).

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A NON-CONTRAST HEAD CT-SCAN. CLICK THE THUMBNAILS TO VIEW THEM.

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A T1 WEIGHTED HEAD MRI WITHOUT CONTRAST. CLICK THE THUMBNAILS TO VIEW THEM.

FINDING THE CENTRAL SULCUS ON AXIAL CROSS SECTIONS: INTRAPARIETAL SULCUS SIGN

The intraparietal sulcus will intersect the post central sulcus which can also be used to confirm the location of the central sulcus. 

The above images are from axial cross sections of a non-contrast head CT scan. They are both the same image, however the right pane is annotated to highlight important anatomy. The above image shows how the intraparietal sulcus (yellow line) connects to the post-central sulcus (blue line). The central sulcus can be found anterior to them both (red line).

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A NON-CONTRAST HEAD CT-SCAN. CLICK THE THUMBNAILS TO VIEW THEM.

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A T1 WEIGHTED HEAD MRI WITHOUT CONTRAST. CLICK THE THUMBNAILS TO VIEW THEM.

FINDING THE CENTRAL SULCUS ON SAGITTAL CROSS SECTIONS: CINGULATE SULCUS/PARS MARGINALIS SIGN

The central sulcus can also be appreciated on sagittal cross sections. Using the location of the cingulate suclcus and the pars marginalis can help localize the central sulcus. It is important to appreciate that the appearance and location of the central sulcus will vary depending upon where the sagittal section is anatomically. At sagittal sections close to the inter-hemispheric fissure, the central sulcus will be found immediately anterior to the pars marginalis. The pars marginalis can be identified relatively easily because it will be connected to the cingulate sulcus.

The images above are from a T1 weighted MRI of the head without contrast. One image is shown in the axial plane (top left) and two identical images are shown in the sagittal plane (middle, right). Both sagittal images are identical, except the right sided image has been annotated to show the location of the cingulate sulcus (yellow line), pars marginalia (blue line), and the central sulcus (red line). The axial section shown demonstrates the level at which the sagittal sections are found anatomically (white line). At this level, the central sulcus is seen immediately anterior to the pars marginalis.

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A NON-CONTRAST HEAD CT-SCAN. CLICK THE THUMBNAILS TO VIEW THEM.

HERE ARE SOME EXAMPLES OF THIS SIGN SEEN ON A T1 WEIGHTED HEAD MRI WITHOUT CONTRAST. CLICK THE THUMBNAILS TO VIEW THEM.

ACKNOWLEDGEMENTS

A very special thanks goes to Dr. Pierre Sasson who made this page possible with his expertise and insight.

 

Page Updated: 11.15.2017