Foot ultrasound (US) has become increasingly important in the assessment of a variety of conditions affecting tendons, joints, ligaments, nerves and other soft-tissue structures. In plantar fasciitis, the typical site of pathological changes is the posterior attachment of the fascia. Main US findings include fascial thickening, hypoechoic echotexture with loss of the fibrillar pattern and blurring of the superficial and deep borders of the fascia. Often, a heel spur is associated on the inferior aspect of the calcaneus. Plantar fascia rupture typically occurs at the middle third of the fascia. Patients with plantar fasciotomy may exhibit US features resembling fascial rupture. Plantar fibromatosis (Ledderhose disease) is a benign condition characterized by nodular proliferation of fibrous tissue that arises from the middle third of the plantar fascia. Demonstration of the continuity of the hypoechoic nodule with the fascia may help to rule out other soft-tissue masses. Plantar vein thrombosis is an uncommon condition of unknown origin that may mimic plantar fasciitis as it causes pain on the plantar aspect of the foot. In the inframalleolar area, a bony prominence of the calcaneus, the peroneal tubercle, separates the diverging peroneus brevis and longus. A hypertrophied tubercle may cause local pain and tenderness in the lateral midfoot as a result of chronic irritation of soft-tissues. In os peroneum fracture, the ossicle fragments have sharp borders and are separated. The distal tibialis posterior tendon may house the accessory navicular (os tibiale externum). If this ossicle is joined to the navicular by a synchondrosis, part of the tendon inserts into this ossicle rather than normally into the navicular and this can cause a painful syndrome. US may be valuable to detect midtarsal ligament tears, occult fractures and plantar plate injuries (turf toe). In the forefoot, Morton neuromas appear as well-defined, fusiform masses elongated along the major axis of the metatarsals. Dorsal longitudinal scans may be helpful to demonstrate the continuity of the mass with the interdigital nerve. External pressure exerted in the web space may help to distinguish intermetatarsal bursitis from neuroma.