In high impact sports sometimes an external ankle rotation happens, when the foot is turned towards the outside with respect to the leg, causing these types of tears.
Thanks to 3d4medical anatomy I created this picture showing most of the anatomical structures involved in this kind of traumas; don’t forget to examine also muscles and neurovascular bundles during your ultrasound exam; it’s no easy at the beginning, but with practice and a good atlas of anatomy, sure you can manage it.
This is the case of a professional football player with an high degree tear of the anterior inferior tibiofibular ligament.
The power-doppler ultrasound dynamic exam shows the hypervascularity of the painful site of injury.

Axial (left) and Coronal (right) T2 weighted Mri scans (0.3 Tesla) of the same patient.