Related Experiment Video
Updated: Jul 17, 2026
A Standardized Protocol for Functional Motor Mapping Using Navigated Transcranial Magnetic Stimulation
Published on: February 27, 2026
Neuroanatomical localization of the 'precentral knob' with computed tomography imaging
Michael C Park1, Marc A Goldman, Min J Park
1Department of Clinical Neurosciences Program in Neurosurgery, Brown Medical School, Rhode Island Hospital, Providence, RI 02903, USA. michael_park@brown.edu
Background/Aims:
The 'precentral knob', a cortical representation of the motor hand function, can be identified and localized consistently using magnetic resonance imaging (MRI) and functional MRI. We present a method of indirectly identifying and localizing the Omega-shaped precentral knob using the anatomical landmarks on computed tomography (CT).
Methods:
CT and MRI obtained within 24 h from 10 patients undergoing a headache workup and found to be negative for any anatomical abnormalities were studied. First, the precentral knob was identified in the CT images. Then, the 'coronal suture line' and 'midline' were identified and used to measure the distance to the precentral knob on both hemispheres. MRI was used to confirm the location of the precentral knob in the CT images based on anatomical landmarks (i.e. sulcal configurations).
Results:
The precentral knob is located 45.1 +/- 5.2 mm posterior with respect to the coronal suture line and 33.9 +/- 3.4 mm lateral to the midline on the right hemisphere, and 44.6 +/- 5.7 mm posterior and 33.2 +/- 2.5 mm lateral on the left hemisphere.
Conclusion:
We present a method of consistently identifying and localizing the Omega-shaped precentral knob, a cortical representation of the motor hand function, using CT.
More Related Videos
Related Concept Videos
01:27Imaging Studies III: Computed Tomography
01:10Computed Tomography
The technique was invented in the 1970s and is based on the principle that as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates...
01:17Cerebellum: Anatomical Regions
Cerebellar Structure
Externally, the cerebellum features a highly convoluted surface with numerous folia (narrow ridges) separated by shallow sulci (grooves). The cerebellum is divided into two hemispheres by a thin median structure known as the vermis. The...
01:20Anatomy of the Brain: Major Regions
The cerebrum is the largest section of the brain and divides into left and right hemispheres, separated by a deep fissure. The cerebral outer layer of grey matter — the cerebral cortex — comprises elevations called gyri and shallow groves called sulci. The inner portion of white matter includes long nerve fibers known as axons, which connect various areas...
01:14Imaging Studies I: CT and MRI
Description of the Procedures
Computed Tomography (CT) scan:
Computed Tomography (CT) scans use X-ray technology to generate detailed images of bones, organs, and tissues. During the scan, the patient lies on a moving table...
01:25Imaging Studies II: Positron Emission Tomography and Scintigraphy
Fundamental Principles of PET