The Throckmorton sign is a slang or joke term used in the field of radiology. It refers to the position of a penis as it relates to pathology on an x-ray of a pelvis. When the penis (visible on the x-ray as a shadow) points towards the same side as a unilateral medical condition such as a broken bone, this is considered a "positive Throckmorton sign," and if the shadow points to the other side, it is a "negative Throckmorton sign."