Pencil drawing of flap turned back and brain retracted at operation to reveal a tumour. There are two labels on the drawing: olfactory nerve and frontal extension. Two outline sketches of the patient's skull, one frontal and one lateral, above the main drawing demonstrate the size and position of the tumour. Annotations on the back read "Jefferson patient's surname 19.11.36".
This drawing features as figure 4 in the publication G. Jefferson, 'Extrasellar extensions of pituitary adenomas. President's address', Proceedings of the Royal Society of Medicine, 1940, vol.33, pp.433-58, in which it is described as a "Huge suprasellar extension in the right frontal lobe. Sketch of tumour as seen at operation".
Initialled by the artist in the bottom right corner of the drawing.