Final answer:
Following a skateboard accident, it is most likely that Mike has a sprained ankle, which is caused by the stretching or tearing of the ankle ligaments, commonly resulting from an inversion injury.
Step-by-step explanation:
When Mike falls off his skateboard and sprains his ankle, the most likely occurrence with this type of accident is a sprained ankle. A sprain refers to the stretching or tearing of ligaments. The ankle, being the most frequently injured joint in the body, can easily be sprained during activities like skateboarding. An inversion ankle sprain, which is an excessive inward rolling of the foot, typically damages the ligaments on the lateral (outer) side of the ankle, such as the anterior talofibular ligament. This is in contrast to a Colles fracture, which occurs when falling onto an outstretched hand, or a Pott's fracture, resulting from forcible eversion of the foot.