Two selected cropped images from a thyroid ultrasound.
The first longitudinal image (labelled CC) shows the pyramidal lobe (open arrows) lying superior to, and contiguous with, the normal isthmus, on the right of the image. Waisting of the thyroid occurs at the junction between the pyramidal lobe and the isthmus.
The transverse image shows the pyramidal lobe in the midline anterior to the trachea with the strap muscles at its lateral aspects.