What does it mean when an injury feels hot?

My brother stepped down, twisted his ankle and fell. When he fell he heard a pop and the outside of his foot hurts. It's starting to bruise on the side and around his toes and his foot feels very warm...any ideas?

The heat just means that it is in the process of healing.
It's called the Inflammatory Response.
The four symptoms are: swelling, HEAT, redness and pain.
There's nothing seriously wrong.
When a part of the body is injured, the capillaries in the blood dilate to allow excess blood flow. This helps the white blood cells tend to and "fix" the area. The heat is actually just the increased blood flow to the area.
If the pain is unbearable...he should get it checked out...but I just wanted to let you know that the heat sensation is normal.
Hope your bro feels better.

possibly a fracture of the base of the 5th metatarsal(foot bone) or the lateral maleolus(fibula-the smaller of the two long bones in the lower leg). the motion of "rolling" your ankle can break these bones. x-rays at either the er or at least an urgent care clinic would be wise.
if you're not convince enough to go, google the terms i mentioned and see if it sounds like what he's feeling. hopefully a bad sprain and no fracture.

See a doctor..Rest the ankle, ice it for a bout 10 mins every 2 hours initially, use a bandage to help decrease swelling and tell him to keep hes foot up. Sometimes when an area is hot it can be a sign the area is infected but i doubt it in this case. Anyhow you should take him to doctors

Warm is not good around a joint area, see a Doctor.

Glad you asked