Reason: evaluate peroneal tendons History: pain TENDONS: There appears to be anomalous anatomy of the peroneal tendons. The peroneus brevis tendon courses distally with the majority of its fibers appearing to insert on the retrotrochlear eminence of the calcaneus, as one would expect from a peroneus quartus, although we see no separate peroneus quartus muscle belly. The peroneus longus tendon appears unusually large, but seems to have a normal course beneath the cuboidal tunnel. There is mild increased signal intensity within the peroneus longus tendon posterior to the distal fibula, suggesting tendinosis, and as the tendon courses beneath the fibular tip, there is mild surface irregularity which we expect represents mild partial-thickness longitudinal tearing. There is a small amount of fluid around the peroneus longus tendon beneath the fibular tip as well. A thin low signal intensity structure extending proximally from the base of the fifth metatarsal may represent a hypoplastic peroneus brevis tendon, which may arise either from the aforementioned peroneus longus or the anomalous tendon inserting on the retrocochlear eminence. The remaining tendons appear intact. Note is made of the posterior tibialis tendon inserting onto a type II accessory navicular.LIGAMENTS: The anterior talofibular ligament margins are slightly irregular and the ligament appears thinned on the T1-weighted images, likely reflecting old injury. The calcaneofibular ligament demonstrates mild increased signal intensity, perhaps representing prior sprain, otherwise the ligament appears intact. The anterior and posterior tibiofibular ligaments are within normal limits. The distal tibiofibular syndesmotic complex is intact. The visualized deltoid ligament appears intact.ARTICULAR SURFACES AND BONE: We see no osteochondral defect. There is a small amount of fluid in the tibiotalar joint, but no large effusion. ADDITIONAL
1.Variant peroneal anatomy as described above.2.Enlargement and increased signal intensity of the peroneus longus suggests mild tendinosis, and mild irregularity of its surface may reflect partial thickness longitudinal tearing.3.Findings suggestive of previous injury to the anterior talofibular ligament and other findings as described above.