Lower T sign (central sulcus)

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The lower T sign is one of the features useful in identifying the central sulcus on cross-sectional imaging.

It relies on identifying the inferior frontal sulcus which intersects the precentral sulcus in a "T" junction, thus defining the precentral gyrus. The central sulcus is the next posterior sulcus.

It should be distinguished from the upper T sign which is the confluence of the superior frontal sulcus with the precentral sulcus.

See also