(A) Note the area of cortical thickening (X) in this ultrasound image of the medial malleolus of a basketball player complaining of an ankle sprain. There is a slight disruption of the cortex that represents either a fracture line or a vascular channel (arrow). The hypoechoic rim above the cortex suggests edema. (B) This Doppler ultrasound image shows a marked increase in blood flow in the area of cortical thickening, strongly suggesting the presence of a stress fracture.
