How can you tell plantar fasciitis from a plantar fascia tear using history and
ultrasound?

History often gives the first clue. Plantar fasciitis—more accurately termed plantar fasciosis in chronic cases—typically causes strong “first-step” pain in the morning or after rest, with symptoms easing as the person moves. A plantar fascia tear usually becomes more painful with continued activity and may follow a sudden overload event, sometimes described as a pull or pop. Both conditions can be tender at the medial calcaneal tubercle, so exam alone may not separate them.

Ultrasound adds clarity. Fasciosis shows a thickened, hypoechoic fascia at the calcaneal insertion—many authors consider thickness greater than 4 mm abnormal—while its fibers remain continuous. A tear shows a focal hypoechoic disruption, often involving the deep fibers near the calcaneal attachment, and typically demonstrates more asymmetry when compared to the opposite side. Combining history with ultrasound improves diagnostic confidence.