This article describes rules for measurement of the frontal lobe on thin SPGR (spoiled gradient recalled echo in steady state) MRI (magnetic resonance imaging) scans. Measurements were performed using a locally-developed software program that allows 3-dimensional reconstruction of images, 'painting' of landmarks on the surface of the brain, and reconstruction of 2-dimensional images in any plane with landmark 'paint' remaining on the surface of the brain. Excellent inter-rater reliability has been achieved for this method. The approach may be particularly useful for studies involving groups of patients whose brains are known to be dysmorphic and who may not, therefore, be appropriate for measurement methods that involve image warping or dependence on arbitrary landmarks for defining the posterior boundary of the frontal lobe.