As of the latest update, Google Chrome and Microsoft Edge have made a breaking change to how file uploads are handled. Once your system installs this update, you will not be able to upload new images. Please use another browser until we can get it fixed.

Supplementary motor area

The supplementary motor area (SMA) is involved in preparing for voluntary movements carried out by the primary motor area (precentral gyrus). It is located on the medial surface of the frontal lobe, contained posteriorly within the medial surface superior frontal gyrus (sometimes referred to as the medial frontal gyrus) just anterior to the paracentral lobule 1

Its posterior border is the primary motor area, whereas its anterior border is defined fairly arbitrary by a line passing tangentially to the most rostral part of the genu of the corpus callosum, perpendicular to the AC-PC line 2. Inferiorly it is bounded by the cingulate sulcus

The supplementary motor area is sometimes divided into two parts, 1) SMA proper and 2) pre-SMA by a second line perpendicular to the AC-PC line, running through the anterior commissure 2

Anatomy: Brain

Anatomy: Brain

Share article

Article information

rID: 48004
Section: Anatomy
Synonyms or Alternate Spellings:

Support Radiopaedia and see fewer ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.